Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/04/21

Area Forecast Discussion
National Weather Service La Crosse WI
1022 PM CDT Thu Jun 3 2021 .SHORT TERM...(This evening through Friday) Issued at 215 PM CDT Thu Jun 3 2021 A shortwave trough will move southeast through the area tonight. The RAP surface-based CAPE is up to 500 J/kg this afternoon and then gradually lowers to less than 100 J/kg tonight. The effective 0-6 km shear climbs into the 25 to 35 knot range by 04.00z and then continues through the early evening. This shear then falls to less than 30 knots overnight. However, with the storms being primarily elevated, it looks like this shear may not be felt by any of the storms. As a result, just stayed with isolated to scattered showers and storms. If any storm happened to become strong, gusty winds would be the primary threat. On Friday, high pressure will build across the area. Soundings suggest that we will mix up into the 750-800 mb range. As this occurs, dew points will likely fall into the lower to mid-50s. There may be even a few upper 40s. These dew points are dry enough that they will keep the heat index from getting out of hand. In addition, they may also help the temperatures in the river valleys to over achieve some. .LONG TERM...(Friday night through Thursday) Issued at 215 PM CDT Thu Jun 3 2021 Record or near record heat builds in for the weekend with continued above normal temperatures into next week with on and off shower and thunderstorm chances Sunday night through Thursday. 582dm heights build in for the weekend and combined with brisk southwest winds and relatively low dewpoints these conditions support warm temperatures in the 80s to lower 90s for the local forecast area. The 850mb thermal axis stretches from the Dakotas into Minnesota and generally stays there. Temperatures from 850mb to 500mb are generally 1 to 3 standard deviations above normal per the NAEFS, with the stronger above normal signal to our west where the thermal axis is. The probability for temperatures in the 90s is 85 to 99% for Saturday per our National Blend Model. Recently, we have had a 2 to 4 degrees cool bias from our local statistics. Our current forecasts are mostly in the 90 to 95th percentile compared to all other guidance, so this is a good start. Although grasses are green, crops are just getting started, so transpiration should be more limited compared to a month or two from now. Dewpoints in the 60s and brisk southwest winds should aid in temperatures climbing to near record or in some cases record levels in the 80s and 90s. The minimum relative humidity should range from 30 to 45 percent Saturday and Sunday combined with southwest winds 10 to 15 mph with gusts to 30 mph Saturday and Sunday during the afternoon. Northeast Iowa and southwest Wisconsin have been dry over the last couple of weeks compared to areas farther north. Most areas have greened up significantly with mainly tall grasses or pine needle areas prone to higher fire weather concerns. A series of shortwave troughs will track across the northern U.S. and by Sunday night, one will be strong enough to push a cold front southward toward the forecast area by around 06Z, however it is uncertain how far south the front will make it before it returns north. Meanwhile, 500mb low pressure over the Southern Plains is progged to lift north. Depending on the frontal timing, this moisture will try to advance northward as well. The current GEFS ensembles mostly clip our area to the southeast Monday with a push a little farther north Tuesday, with better chances for rain Wednesday. With a front to the north, the showers and thunderstorms there and attendant boundaries may also play a role in where storms develop next week. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 1021 PM CDT Thu Jun 3 2021 Main taf concern are potential for showers impact both RST/LSE taf sites tonight. A disturbance embedded in the northwest flow aloft will track into central Wisconsin tonight. At this time...the better moisture convergence/lift will be east of the taf sites and any shower development is expected to mainly be along and east of the Mississippi River. At this time will leave mention of showers out of the tafs. The other concern is low level wind shear at both taf sites. Wind speeds increase aloft tonight and allow for low level wind shear to develop and continue to around 12 to 14z Friday. VFR conditions will prevail into surface ridge axis centered along the Minnesota/Wisconsin border provides mostly sunny skies Friday. && .CLIMATE... Issued at 215 PM CDT Wed Jun 2 2021 It continues to look like we will have the potential of seeing some high and warm low records either tied or broken. We put together a web page which has the record highs and warm lows from Friday into the weekend. It also provides 90-degree climatology for several location in our area. This page can be found at && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Boyne LONG TERM...Zapotocny AVIATION...DTJ CLIMATE...Boyne
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
1009 PM CDT Thu Jun 3 2021 .DISCUSSION...Air mass has stabilized over the region behind the convection that has moved offshore with temperatures in the upper 60s to lower 70s. SPC mesoanalysis shows MLCAPE values from 1000-1500 j/kg over the offshore waters. The outflow boundary just past the near shore waters may drift back toward the coast during the overnight hours. Deep moisture will still be in place over the coastal plains. The 50H low will remain over the Edwards Plateau while the 85H low will be to the southeast over the Rio Grande Plains. Models show low level convergence will increase along the coast overnight with additional upper level support from an upper level jet streak moving northeast into the region. Latest Hi-res models are not optimistic with regards to redevelopment over the coastal plains overnight, but the environment will be favorable for storms to reform later tonight. Kept the Flash Flood Watch going for the coastal plains, but cancelled the watch for the western 4 counties. Showers may redevelop overnight, but the threat for heavy rainfall will be to the east. && .PREV DISCUSSION... /Issued 654 PM CDT Thu Jun 3 2021/ AVIATION...00Z TAFs Outflow boundary from thunderstorms has made it to the coast with the stronger storms from Port Aransas to Port O`Connor moving to the northeast. Showers will affect the coastal sites through 03Z with thunderstorms possible until 02Z. MVFR ceilings/vsbys will occur for the coastal plains with periodic IFR ceilings/vsbys with the stronger storms along the coast. A brief improvement will occur late this evening with vsbys while MVFR ceilings persist. The outflow boundary is expected to stall over the near shore waters early this evening and drift back toward the coast by the overnight period. Expect additional showers and storms will form near the coast and affect the coastal plains from the early overnight period through Friday morning, especially over the Victoria Crossroads. MVFR ceilings/vsbys will be prevalent with IFR ceilings/vsbys expected with the stronger storms. Convection may linger into the afternoon hours but confidence is low at this time. For the Brush Country, post outflow boundary low clouds will affect the LRD area early this evening with IFR ceilings. Expect the ceilings will lift to MVFR late this evening. Scattered showers will move into the region during the overnight period, but the threat for heavier rainfall and thunderstorms may be east of this area. MVFR ceilings are expected to persist over the Brush Country during the overnight into Friday. PREV DISCUSSION... /Issued 446 PM CDT Thu Jun 3 2021/ SHORT TERM (Tonight through Friday Night)... The ECMWF/NAM deterministic runs predict increasing upper forcing during the period associated with the approaching upper trough/low. NAM predicts PWAT values well above normal during the period. The GFS, and to a lesser extent the RAP, maintains a weak quasi-stationary boundary across the CWA overnight, while the NAM keeps it farther south. Expect scattered/numerous convection during the period. The RAP and NAM predict thermodynamic profiles conducive to efficient rainfall production (warm nearly saturated 0-4km layer and moderate CAPE) after 06z Friday, with significant 0-6km vertical shear as the caveat. Likely that rainfall totals over many areas exceed hourly FFG values. Concur with WPC regarding the Marginal/Slight Risk over the CWA tonight/Friday. Coordinated with BRO WFO and issued a FFA for all of the CWA for the 00-12z Friday period. It will likely need to be extended beyond 12z Friday yet will defer to the mid shift. LONG TERM (Saturday through Thursday)... Rain chances will continue through the extended period, but may some drying by the end of next week. A mid/upper level low will meander across TX through Saturday with embedded short waves rounding its base and moving across S TX. Models prog the environment to be unstable with minimal CIN and ample amount of moisture. PWATs are progged to range from 1.6 inches across the west to 1.9 across the northeastern portions of the CWA. Models are also hinting at a weak boundary/convergence zone across the northwestern CWA Sat morning and increasing diffluence aloft. All of these features combined will be conducive for sct to num showers and thunderstorms on Saturday with possibly a few strong storms. QPF values are not quite as high for Sat as previous runs, but the forecasted environment will have the potential for locally heavy rainfall, especially across the Victoria Crossroads. The Weather Prediction Center has a marginal risk for excessive rainfall for the VCT area on Sat. Slightly drier Sunday as the upper low axis shifts east of the area and brings dry mid levels across S TX. Still enough moisture for iso to sct convection with the better chances remaining across the VCT area. Models prog another short wave embedded in the northwest flow aloft to move southeast across the region Monday bringing another round of convection. This pattern continues through the middle of next week. Warmer max temps Sunday through mid week combined with a humid environment could lead to afternoon heat indices reaching 105 across the western CWA. Monday may see heat indices ranging from 105 to 108. MARINE... The combination of a developing upper level low pressure system and copious moisture will contribute to scattered/numerous showers and thunderstorms late tonight through Friday. A weak to moderate, to sometimes moderate, onshore flow can be expected Saturday through the middle of next week. Isolated to scattered showers and thunderstorms will be possible daily. && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 71 82 71 83 73 / 90 70 60 60 30 Victoria 69 81 70 82 70 / 90 70 70 80 50 Laredo 70 87 71 90 72 / 60 60 50 30 10 Alice 69 84 68 86 70 / 90 70 60 50 20 Rockport 72 84 73 84 74 / 80 70 60 60 40 Cotulla 71 86 70 88 72 / 60 70 60 50 20 Kingsville 71 82 70 85 72 / 90 70 60 50 20 Navy Corpus 73 82 74 83 76 / 80 70 60 60 30 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...Flash Flood Watch until 7 AM CDT Friday For the following zones: Aransas Islands...Bee...Calhoun Islands...Coastal Aransas... Coastal Calhoun...Coastal Kleberg...Coastal Nueces... Coastal Refugio...Coastal San Patricio...Goliad...Inland Calhoun...Inland Kleberg...Inland Nueces...Inland Refugio... Inland San Patricio...Jim Wells...Kleberg Islands...Live Oak...Nueces Islands...Victoria. GM...None. && $$ TMT/89...SHORT TERM
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
959 PM CDT Thu Jun 3 2021 .UPDATE... Expecting some stabilization behind the convection across South Central Texas tonight. We have lowered the POPs for the rest of tonight. Short term models still show some chance for rain especially along the Rio Grande. && .PREV DISCUSSION... /ISSUED 635 PM CDT Thu Jun 3 2021/ AVIATION... For the Austin and San Antonio terminals the rain has nearly come to an end for the evening. Ceilings have lifted to VFR and what rain is continuing is very light and having no effect on visibility. Showers may move over the airports for the next couple of hours, but will not have any effect on flying category. Ceilings will lower to MVFR later this evening and then to IFR overnight. Showers and thunderstorms will develop again overnight and continuing through the day Friday. Ceilings will only improve to MVFR Friday afternoon. At DRT, they are currently VFR and will remain that way through the evening. There are isolated showers and thunderstorms in the area and it possible that they move over the airport during the next few hours. If any do, they will likely not change the category. The ceiling will lower to MVFR later tonight and stay that way through Friday morning. Showers and thunderstorms will be possible Friday afternoon. PREV DISCUSSION... /ISSUED 232 PM CDT Thu Jun 3 2021/ SHORT TERM (Tonight through Friday Night)... What a wet day it has been across South Central Texas. While most spots saw a good inch to inch and a half of rain some spots across the Hill Country, Austin Metro, and then parts of Southern Bexar and Wilson County have seen 3 to 4 inches of rainfall with localized higher totals. This has caused issued with area low water crossings with even just the quick 1/2 inch to 1.5 inches causing water to flow over them due to the saturated ground. The good news in the short term is that the mesoscale models are in good agreement (and are decently supported by the global models) that this activity should continue to work its way to the east and south through the afternoon. The heaviest rain for the rest of the day will be along the Coastal Plains with more light rain across the I-35 corridor. The PoP forecast for the short term is roughly based on the SPC HREF, and while one would normally use that for severe weather, have utilized it for our rainfall forecasts this go around, as no severe weather is expected during the short term. In general the late evening through the early overnight hours should be fairly quiet with light rain ending. Have left 30-40 PoPs across the area, but even these may be too high with the drying trend of the HRRR and other models. The next round of rainfall for the area will begin some time late tonight into Friday morning. The HREF members vary with the NAM Nest showing precipitation redeveloping around 4am, with most of the other models holding off until around 7am. The Texas Tech WRF, which did a decent job with today`s round of precipitation holds off redevelopment until late morning on Friday. Have sided with the earlier onset of the precipitation here as it seems to be the consensus of the high resolution models at this time, but as we saw yesterday evening much can change in these models, even over a 6 hour period so confidence in the timing is low. What seems to be certain is another round of rainfall, this time developing from the south and moving north across our area at some point during the day on Friday. Synoptically the upper low that has been plaguing us over the last week will be to the Big Bend Region by 7am on Friday. This will help to enhance the rain chances for the day on Friday and into Friday night. The low will take its sweet time moving across the state with it only reaching the Central Part of Texas by Saturday morning. Unsurprisingly the synoptic models have the heaviest rainfall occurring at different times over the short term, but they all generally agree that tomorrow through Saturday will be another wet period. The ECMWF continues to be the wettest of the models, while the GFS focuses the heaviest rainfall late tomorrow and into Saturday. The NAM on the other hand has much of the heavy rainfall during the day tomorrow. Lets talk messaging and impacts to wrap this up. First off with the rains today and over the last several days much of the area has seen anywhere from 2 to 6 inches of rain. As was demonstrated today, even a quick inch in urban areas can cause low water crossings to flood. Localized flooding will continue to be the main concern with the Weather Prediction Center introducing a slight risk of excessive rainfall for Friday. Think that a Flash Flood Watch is a wise choice now that we are very well primed for more flooding. Have decided to hold off for this afternoon with the current system moving out. Future shifts, either the evening once things calm down, or the overnight shift will reconsider the need for a Flash Flood Watch and possibly issue one for parts of the area. While the rivers have not seen big impacts thus far low water crossings have been with over 100 still closed on ATXfloods, and 17 closed across Bexar county on Bexarflood. These will continue to be the main hazard so always remember Turn Around, Don`t Drown. This is honestly a great weekend to just make a 3 day weekend, stay home and off the roads, watch your favorite streaming service, and enjoy the rain outside from the safety of your home. LONG TERM (Saturday through Thursday)... An upper level low will be centered over Central Texas on Saturday into Sunday with a lower level flow off the Gulf of Mexico and an unseasonably moist airmass over our area. Upward forcing continues the scattered to numerous showers and thunderstorms with the main threat being heavy rains causing flooding due to moist soils from earlier rains. The greatest threat for heavy rains and flooding will be from the Hill Country across the I-35 corridor to near the Coastal Plains. Rainfall amounts of 1 to 2 inches with isolated amounts of 4+ inches can be expected across those areas. Cannot rule out a strong storm or two with gusty winds possible. The upper level low gradually lifts to the northeast while weakening into a shear axis across eastern Texas early to middle part of next week. However, a moist airmass remains over area due to lower level flow off the Gulf of Mexico. The chances of showers and thunderstorms continue, although, with time become mainly diurnally forced by solar heating by the middle of next week. The threat for heavy rains will become much more localized, as well. Due to clouds and rain, high temperatures will remain below normal, though trend closer to normal by later next week. Low temperatures should be around normal. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 66 79 67 80 68 / 40 80 60 80 50 Austin Bergstrom Intl Airport 66 79 67 80 68 / 50 80 60 80 50 New Braunfels Muni Airport 65 80 68 81 69 / 40 80 60 80 50 Burnet Muni Airport 64 78 66 78 66 / 40 80 50 70 40 Del Rio Intl Airport 69 83 69 85 71 / 50 60 40 30 10 Georgetown Muni Airport 65 78 67 80 67 / 40 80 50 80 50 Hondo Muni Airport 65 80 67 81 68 / 40 80 60 60 30 San Marcos Muni Airport 66 80 67 81 67 / 40 80 60 80 50 La Grange - Fayette Regional 69 82 70 83 70 / 60 80 60 80 50 San Antonio Intl Airport 66 79 68 80 69 / 40 80 60 80 40 Stinson Muni Airport 67 81 69 82 69 / 40 80 60 70 40 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term/Aviation...05 Long-Term...Platt
Area Forecast Discussion
National Weather Service Houston/Galveston TX
717 PM CDT Thu Jun 3 2021 .AVIATION [00Z TAF Issuance]... Quite a bit of activity ongoing across SE TX at this time as a strong shortwave moves through the area. Will keep the mention of TSRA/VCTS in for a few more hours for most sites...but will expect the activity to become more stratiform in nature before coverage decreases further by midnight. IFR/MVFR CIGS are fore- cast to develop overnight through early tomorrow (Fri) morning during this brief lull from this rains. Short-range models are indicating another round of scattered showers/storms moving in from the W/SW around mid/late tomorrow morning (12-15Z) as yet another shortwave moves into the region. Coverage should fill/ become fairly widespread tomorrow afternoon with both VIS/CIGS hovering around MVFR. 41 && .PREV DISCUSSION... /ISSUED 404 PM CDT Thu Jun 3 2021/ SHORT TERM [Through Friday Night]... Today is looking almost identical to yesterday with showers and thunderstorms developing along the sea breeze. A shortwave ejecting off of a deepening upper level low in West Texas will move across our area into the evening enhancing the diurnally driven convection. PWATs are over 2 inches this afternoon, so locally heavy rainfall will be possible causing ponding along low lying areas. Based short term PoPs towards the HRRR as it has been initializing fairly well all day. Precipitation will become largely widespread by the late afternoon into the evening for most of the area but the immediate coastline. May want to plan for longer commute times for the evening rush tonight. There will be a lull in the precipitation late this evening into tonight, but this won`t last long as scattered showers and thunderstorms fills back in from west to east by day break as yet another shortwave passes through the area. The upper level trough becomes a closed low early Friday and begin its slow approach to Southeast Texas through the day on Friday. There again remains a chance of locally heavy rain through Friday evening. Grounds are fairly well saturated from weeks of rainfall, so will need to watch closely for any flooding concerns. The WPC has placed the western half of the CWA in a Slight Risk of the area for Excessive Rainfall. Total rainfall through Friday night will be around 1 to 3 inches with locally higher amounts possible. Temperatures through the short term will not vary much thanks to overcast skies. Low temperatures tonight will dip down to near 70, then temperatures rise to near 80 in the afternoon tomorrow, then back down to near 70 Friday night. Fowler LONG TERM [Saturday through Thursday]... Environmental conditions will remain favorable for an active weather pattern this weekend through the upcoming week. Confidence in the potential for flooding across portions of SE Texas during the extended period has increased as models get a bit more in sync with a synoptic pattern that reflects favorable conditions for periods of heavy rainfall. An upper level low over Western and Central TX is progged to move slowly eastward Saturday, continuing favorable jet dynamics for storm development across Southeast TX. In addition, a few smaller disturbances are expected to round the base of the associated trough and move over the local area from time to time, further enhancing the potential for storm activity. With persistent southerly flow continuing to provide good surface moisture transport over the local area (PWs of 1.8 to 2.0 inches), periods of locally heavy rainfall are likely on Saturday. The upper low is expected to reach Eastern/Northeastern TX by Sunday and meanders over this area through Monday. Although the global models weaken the low/trough over the Southern Plains, pulses of abundant surface moisture will continue to move through the area, enough to maintain periods of showers and thunderstorms both Sunday and Monday. Beyond that timeframe, southerly flow will remain over the local area, maintaining PWs of 1.7 to 2.0 inches through the end of the forecast period. Unfortunately, models are now keeping the upper level ridge more to the west midweek, thus, extending the potential for active weather through the end of the forecast period. Total rainfall amounts of 4 to 7 inches can be expected during the next 7 days, locally higher amounts are possible with very slow moving storms or training. Considering the spectrum of expected rainfall amounts, along with the fact that we will have saturated soils lurking across portions of the CWA and water levels running high in a few of our rivers, Southeast TX could experience some flooding issues during the next few days. Flash Flood Watches may begin to be issued in the next day or so. Please stay alert and prepared in case one is issued for your area. High temperatures this weekend will be in the low to mid 80s and in the mid to upper 80s next week. Low temperatures will generally be in the upper 60s to low 70s inland through early next week, and in the low to mid 70s through the end of the period. -- Given it`s the long term period, changes to the forecast could occur, although at this time, most models are in fairly good agreement with the long term synoptic pattern. 24 MARINE... Light winds will continue through the end of the work week across the bays and waters along with seas of 1-3 feet. Winds increase this upcoming weekend, possibly requiring Caution flags with seas building up to 6 feet as a long fetch from the southern Gulf develops. Chance of showers and thunderstorms can be expected each day, with the heaviest activity expected to occur Friday through Monday. Tides levels may also increase Sunday into early next week. For those planning to visit the beaches this weekend, strong rip currents could occur across the Gulf facing beaches. Make sure to monitor the local beach advisories. 24 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 69 79 68 82 69 / 50 80 50 80 50 Houston (IAH) 70 80 70 82 71 / 60 80 60 80 60 Galveston (GLS) 75 81 75 82 76 / 70 70 60 70 60 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ Discussion...99 Aviation/Marine...99
Area Forecast Discussion
National Weather Service New Orleans LA
929 PM CDT Thu Jun 3 2021 .EVENING UPDATE... No significant forecast updates planned at this time in the short term. 00z LIX sounding was rather moist and unstable with a precipitable water value of 2.00 inches, which is in about the top 5% climatologically for early June here. We continue to be in southwest upper flow, and back to the southwest, the soundings at Brownsville and Corpus Christi also have precipitable water values around 2 inches, so don`t really anticipate much change in available moisture. We continue to see isolated to widely scattered convection fire along the Mississippi and Louisiana coasts, even after sunset as weak impulses move through the southwest flow. While the HRRR solutions through 00z are drier tonight than they have been the last couple of nights, not really comfortable with that trend based on the soundings and radar. Will hold onto current depiction of precipitation trends, mainly near the coast. A few spots will see locally heavy rain which may require issuance of Flood Advisories/Warnings, but large portions of the area could be dry overnight. 35 && .PREV DISCUSSION... /issued 400 PM CDT Thu Jun 3 2021/ SHORT TERM (Tonight through Sunday)... Active pattern will persist through the period. Long wave upper trough extends from north of the Great Lakes into the Middle Mississippi Valley and back into Texas. This trough will gradually lift northeastward Friday, leaving behind a lingering upper low over Texas. Even with the trough lifting out of the area, expect to see scattered to numerous showers and thunderstorms on Friday. Going into Saturday, expect to see a more noticeable gradient in rain chances and coverage. As the upper trough moves farther northeast and over the Atlantic, we`ll lose the influence of that feature. However, there will still be a closed upper low centered over Texas and the influence of that feature should still allow for scattered to numerous showers and storms, with the highest rain chances (around 60 percent) across areas nearest the Atchafalaya River and lowest chances (around 30 percent) across Jackson County on the MS Coast. By Saturday night the low will begin to move northeastward, and a fairly impressive slug of moisture will start to transit the area from Southwest to northeast, leading to high rain chances and potential for heavy rain, especially from the second half of Saturday night through Sunday. Area average rainfall is currently forecast in the 1-2 inch range, but there is potential to see substantially higher amounts on the local scale - especially if any given area sees multiple rounds of storms. As details become clearer, may be able to narrow down areas of greatest risk and increase the rain totals in those areas, but for now, most of the area appears as though it could be under the gun. Will also mention that strengthening onshore winds will lead to higher tides Sunday and possibly into the first part of next week. Current probabilistic guidance indicates high tides could reach near or just over 1 ft MHHW at the Bay Waveland and Shell Beach gauges Sunday and Monday, so may end up needing to issue a coastal flood advisory for areas near the Rigolets through Bay St. Louis. Will need to monitor conditions and trends over the next couple days. Any impacts should be substantially less than what was experienced last month. For comparison, winds over the water are generally forecast in the 10-15 knot range for this period while the event last month saw several days of winds in the 20-30 knot range. LONG TERM (Sunday Night through Wednesday Night)... As we move into Sunday night, the upper low will open up and the deepest moisture will begin to pull away from the area. However, weather remains unsettled with the now upper trough very slowly drifting eastward across the Gulf Coast region. This will keep the active and unsettled weather pattern in place with daily showers and storms. Highest rain chances will generally be during the afternoon hours with the aid of daytime heating. AVIATION... VFR conditions will prevail through most of the period outside of showers and thunderstorms. Also some potential for patchy fog and low ceilings near daybreak in areas where ground moisture is higher from recent rainfall. MARINE... Bermuda high pressure off the southeastern US coast will continue to keep an onshore flow through the forecast period. A moderate gradient pattern will allow for winds to increase to the 10 to 15 knots going into the weekend. Seas will gradually respond, building to 3 to 4 feet as well. Scattered showers and thunderstorms each day will lead to locally higher winds and seas, with a few of the stronger storms possibly resulting in wind gusts in excess of 30 kts. && .PRELIMINARY POINT TEMPS/POPS... MCB 68 83 68 83 / 30 60 20 50 BTR 70 84 69 83 / 30 70 20 50 ASD 70 85 69 85 / 40 60 10 40 MSY 73 85 74 84 / 50 60 10 50 GPT 71 84 72 85 / 40 50 10 40 PQL 70 85 69 85 / 30 40 10 30 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$
Area Forecast Discussion
National Weather Service Marquette MI
732 PM EDT Thu Jun 3 2021 .SHORT TERM...(This evening through Friday) Issued at 414 PM EDT THU JUN 3 2021 WV imagery and RAP analysis indicated a mid/upper level ridge from the southwest CONUS to Saskatchewan and a trough into the central Great Lakes resulting in northwest flow toward Upper Michigan. A shortwave trough into western Upper Michigan supported an area of light rain showers through portions of central Upper Michigan into northern Wisconsin. Cloud cover with the shrtwv has been thick enough to reduce insolation and instability to support tsra. Some showers have developed along Lake breeze boundaries but have been relatively weak. Rest of today and tonight, expect there still may be enough heating with thin spots in the clouds for MLCAPE values to around 500 J/Kg and some isold tsra to develop. Otherwise, as the remaining showers will slide to the southeast as the shrtwv moves out of the area. Lingering low level moisture along with clearing and temps dropping into the low to mid 50s will result in potential for patchy fog development. Friday, as the mid level ridge builds into the region with increasing southwest low level WAA (850 temp to around 18C) temps will climb into the mid and upper 80s. Capping will be strong enough to preclude convection. SSW winds at or below 10 mph will be weak enough to lake breeze development off of Lake Superior with some cooler air near the shore. .LONG TERM...(Friday night through Thursday) Issued at 350 PM EDT THU JUN 3 2021 A fairly broad ridge over the plain states, will continue to move toward the upper Great Lakes region during the weekend. The ridge axis will reach upper Michigan by early Sunday. Upper trough will deepen over the western U.S. This trough has a tough time moving into the upper great lakes. An associated cold front approaches the area early next weak then stalls out. The precise location where it stalls is still in question, but nevertheless, the best chance for convection during the extended time frame will be Monday and Tuesday. It currently looks like any ridge topping severe storms will miss Upper Michigan, but that can change. For Wednesday, the ridge builds back in and the surface front starts moving north as a warm front. The chance of showers still exists with this scenario, but deep convection looks capped off. With the ridge dominating our weather pattern, expect above to much above temperatures at least through the middle of next week. The hottest days will be Saturday and Sunday with many locations going over 90. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 724 PM EDT THU JUN 3 2021 Main concern for aviation interests for this TAF period will be the potential for fog developing during the overnight hours at all three terminals. Atmospheric moisture continuing to advect into the area and low dewpoint depressions, along with relaxing winds and a good chunk of clouds moving out of Upper Michigan will set the stage for fog potential. Therefore, have continued to mention this within the TAFs but will need to keep an eye once the fog becomes evident to determine just how low visbys will go. Currently, it appears KSAW has the highest chance of seeing the lowest visbys (below 1 SM), followed by KIWD and KCMX. Aviation interests should stay locked in with the latest obs and potential updates/amendments as necessary. Once the fog dissipates tomorrow morning, VFR conditions will dominate through the end of the period, with generally light winds continuing. Could see a CU field develop in the KSAW area tomorrow afternoon, courtesy of the lake breeze. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 414 PM EDT THU JUN 3 2021 Expect winds across Lake Superior to be mostly under 20kt through F Fri. Stronger winds are then possible on Fri night as low pres moves e across northern Ontario. Wind gusts of 20-25kt will be possible Friday night into Sat morning. Another period of stronger winds is possible Sat night into Sun as another low pres moves e to southern Hudson Bay. Although the air mass will be very warm, resulting in very stable conditions over the waters, sw to s winds could occasionally gust to 25kt to perhaps as high as 30kt at high obs platforms at some point Sat night and Sun. Fog may become an issue in the coming days as air mass over the area becomes increasingly humid. However, with only minimal rainfall confidence for widespread fog is low. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...KFM AVIATION...lg MARINE...JLB
National Weather Service Morristown TN
1011 PM EDT Thu Jun 3 2021 .UPDATE... EVENING UPDATE. && .DISCUSSION... Radar shows the convection over the Plateau has generally been weakening. A strong storm still cannot be ruled out, but overall the threat of strong to severe storms has diminished. Will remove severe mention from the HWO but will keep the mention of locally heavy rainfall and possible localized flooding. Will drop thunder to no more than slight chance, and will tweak PoPs/Wx to better fit latest CAMS and radar trends. Will also make tweaks to temps/dew points with this update. && .AVIATION... 00Z TAF DISCUSSION. There will be showers and a few thunderstorms around early in the period. Will include VCTS all sites with a tempo group for the period when showers look most likely. Once the showers move out, at least partial clearing and light winds will provide the opportunity for significant fog development. Still some uncertainty in the details of any fog, but for now will take all sites to IFR prevailing with tempo LIFR vsby/cigs. Will see improvement to VFR all sites after sunrise. Winds will generally be light. && .PREV DISCUSSION... /ISSUED 318 PM EDT Thu Jun 3 2021/ SHORT TERM...(Tonight and Tomorrow)... Key Messages 1) Scattered showers and storms continue this afternoon into the evening hours. 2) An isolated severe thunderstorm is still possible through early evening, wind damage is the main concern. 3) Fog is possible overnight areawide. Discussion... Scattered showers and a few storms continue across the area this afternoon. Most of the area remains fairly cloudy but some partial clearing has been seen over the Cumberland Plateau over the past few hours. There has been better clearing across middle TN and northern AL and this is where new storms are currently developing. The latest HRRR shows an uptick in shower and storm activity across our area beginning around 20/21z. Then, scattered showers and storms continue until around midnight as the cold front approaches and moves through the area. The greatest chance for any strong-to-severe storms looks to be across the Cumberland Plateau, southern TN valley, and southwest NC as these areas currently have the most instability. Northeast TN and southwest VA are the most stable so they have a lesser chance of seeing any stronger storms. Models do show instability increasing northeastward into the central TN valley over the next several hours so the central TN valley could also see some strong storms as well. Wind damage is the main concern but we have noted some weak and broad rotation with some of the cells down along the TN/GA line. This is due to the weakly sheared environment that is in place with roughly 15 to 20kts at 0-1km and 20 to 30kts at 0-3km. So we will continue to monitor storms closely for any quick spin-ups. Lastly, a few isolated areas across the southern TN Valley has seen 2 to 3 inches of rain so if these areas see anymore heavy rainfall flooding could become a concern. The HRRR shows showers exiting the area generally after midnight as the front pass through the area. Guidance is hitting the fog pretty hard tonight so have fog in areawide in the grids. Overnight lows will dip down into the upper 50s to low 60s. Tomorrow, the upper trough is lifting northeast out of our area but a few scattered showers and a possible storm are possible before it completely exits. This will mainly affect northeast TN and southwest VA. Drier air moves in later in the day behind the front with clearing skies. Highs will be in the upper 70s to low 80s. SR LONG TERM...(Friday night through Thursday)... Key Messages 1) Warming trend and drier weather this weekend. 2) Increasing moisture, clouds, and rain chances next week. Discussion... Friday night into Saturday, an upper low will remain situated over Texas while upper heights build over the southern Appalachians in response to the departing upper trough and better alignment with weak northern stream ridging. Expect a warming trend for Saturday and Sunday in response to this low/mid level southerly flow regime. Warmest temps on Saturday will be in the southern valley, but as H85 flow turns SSELY on Sunday expect the warmer temps to shift to the northern half of the valley. The TX upper low opens up late Sun but the resulting upper trough/remnant upper low remains over that same general area into early next week before meandering eastward through the end of the period. The significance of this is that this continued southerly low/mid level flow regime will bring increasing moisture and rain chances to the forecast area beginning Sunday evening, but especially ramping up Monday onward. This pattern will favor diurnally driven convection, with showers and thunderstorms forming in the mountains and plateau areas by early afternoon and pushing into the valley during the evening. However, suspect there will be some sporadic nocturnal convection as well due to weak but persistent isentropic ascent Sunday night onward. Timing that will be difficult so will favor diurnally driven PoPs for the time being. After the warmup on Sat and Sun, the increased cloud cover and rain chances next week should bring highs back down to around normal values. CD && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 64 85 63 89 67 / 50 10 0 10 10 Knoxville McGhee Tyson Airport, TN 64 82 62 87 64 / 50 10 10 10 10 Oak Ridge, TN 61 83 61 87 63 / 70 10 10 10 10 Tri Cities Airport, TN 61 79 57 85 60 / 50 20 10 10 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$
Area Forecast Discussion
National Weather Service Nashville TN
808 PM CDT Thu Jun 3 2021 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Surface boundary continues to progress slowly eastward across the Cumberland Plateau, with only a few remaining cells still showing up on radar. Expect these to exit the region in the next couple of hours. HRRR shows no redevelopment afterwards. Look for patchy fog overnight as radiational cooling takes over. Fog could be dense in a few spots owing to the wet ground and lingering high dew points. Current grids seem to have a good handle on the overnight forecast, so no changes are planned at this time. && .AVIATION... 00Z TAF DISCUSSION. BNA/MQY/CKV/CSV...A cold front has just about made it all the way across Middle Tennessee. The only remaining convection is occurring along and just west of the Cumberland Plateau in the vicinity of the surface boundary. Look for this activity to exit the region by early evening as the front continues eastward. Tonight looks to be a good night for radiational cooling, and with a wet ground and high dew points, we are expecting areas of fog. So we`ll include mention of fog in the TAF`s. Tomorrow, expect VFR wx and light winds. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......08 AVIATION........08