Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/13/22

National Weather Service Bismarck ND
922 PM CDT Fri Aug 12 2022 .UPDATE... Issued at 919 PM CDT Fri Aug 12 2022 Models are in pretty good agreement with fog developing northwest, central, and east tonight, so did go with areas versus patchy. Also increased sky cover this evening with no signs of the low stratus going anywhere across my east, with an expansion west expected overnight. UPDATE Issued at 639 PM CDT Fri Aug 12 2022 The forecast for this evening remains on track. Low clouds linger across much of the eastern half of the state. Should see some improvement northeast, but latest RAP and HRRR keep the sky mainly cloudy across the James Valley through much of the night and into Sat morning. Didn`t go all in with these models, but did trend sky cover upwards. Still on track for fog development late tonight. For now will keep patchy wording, but I may up the coverage with the next update based on the RAP and HRRR model solutions, the rich boundary layer moisture in place, and light winds projected from the highway 83 corridor and east. && .SHORT TERM...(This Evening through Saturday) Issued at 234 PM CDT Fri Aug 12 2022 The primary concerns in the short term period will be fog potential tonight and thunderstorm chances Saturday. Afternoon visible satellite imagery shows mainly high clouds in western parts of the state with stratus still lingering in the central and east. Short term models still suggest the stratus should diminish this afternoon, however there has been a fairly persistent signal in the HRRR that low clouds and fog are possible again later tonight. This makes sense with a surface ridge axis in place from across the central and eastern parts of the state, though there is a bit more of a pressure gradient in the west. NBM point forecasts even suggest IFR and / or LIFR are possible, especially central and east. Will introduce patchy fog for tonight as a start and see how things progress. Tonight should be dry, though a weak wave moving across Montana in the upper ridge could trigger a few showers / thunderstorms to our west. In general CAMS suggest those should weaken / die out before reaching North Dakota tonight. That changes on Saturday with HREF paintball composite reflectivity greater than 40 dbz showing more short term model solutions bringing at least isolated activity into the western parts of the state. It appears those should not have much instability to work with at least initially, but MUCAPE values do approach 1000 J/kg in parts of the west during the afternoon. Deep layer shear values also increase by afternoon, and SPC has now placed parts of western North Dakota into a Marginal Risk for Day 2 (Saturday). We plan to acknowledge that in the updated Hazardous Weather Outlook by introducing the mention of a potentially strong to severe storm Saturday afternoon and evening in parts of the west. .LONG TERM...(Saturday Night through Friday) Issued at 234 PM CDT Fri Aug 12 2022 A stronger wave appears to move through the upper ridge Saturday night with an increasing model consensus for the better chances of showers / thunderstorms in the northern part of the state. Beyond Saturday night, the rest of the long term period will generally feature an H5 ridge across the western / central United States with waves riding across it at times in the Northern Plains. Though the big picture is fairly clear in regards to the overall pattern, details regarding the small waves moving through the ridge are difficult to time. Will continue to follow along with the NBM overall in the later periods which seems to capture the trends. One thing to note towards next weekend (and a little beyond) is that some model solutions begin to suggest a break down in the upper ridge. That being said, cluster analysis would suggest that is a lower probability scenario than the ridge persisting. && .AVIATION...(For the 00Z TAFS through 00Z Saturday Evening) Issued at 639 PM CDT Fri Aug 12 2022 Low clouds still slow to clear in the east, mainly for KJMS where MVFR conditions remain and will likely persist. Low clouds and fog are forecast to redevelop tonight, impacting KBIS, KMOT, and KJMS. Some short term model solutions would suggest IFR conditions in low clouds and fog possible as well. Conditions should improve with time Sunday morning after 14Z or so. Chance for thunderstorms increase mainly across the northwest (KXWA) after 12Z. Low probability so did not introduce this for the TAF with this issuance. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...NH SHORT TERM...King LONG TERM...King AVIATION...NH
Area Forecast Discussion
National Weather Service Boston/Norton MA
1042 PM EDT Fri Aug 12 2022 .SYNOPSIS... Dry and quiet weather for the most part as high pressure builds in from the Great Lakes area. Low chance of an isolated shower overnight and early Saturday morning as a weak boundary passes east of Cape Cod. Comfortable temperatures with low humidity values expected this weekend along with mainly sunny skies. An unsettled and slow-evolving weather pattern then develops into the middle of next week. While not yet set in stone, the potential exists for welcomed rains Tuesday through Thursday. Near to below normal temperatures are likely this weekend into midweek. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 10:30pm Update... No major changes to the forecast. currently watching a couple of showers in southern RI that should dissipate in the next hour or so. Also monitoring a precip shield south of the region that may clip Nantucket and the Cape overnight. Previous Discussion... 7:50pm Update... * Very low chance of an isolated shower this evening, especially near seabreeze boundaries across eastern MA. * Elevated fire weather concerns for Massachusetts through this evening as a result of lower humidity and ongoing drought conditions. No major changes to the forecast this evening. Watching a pair of isolated showers across portions of eastern MA. These showers developed along the seabreeze front. With the loss of daytime heating, expecting these showers to dissipate quickly over the next hour or so. The rest of tonight should feature mainly dry weather across southern New England. Just starting to see the northern edge of an area of rainfall approaching the Cape and islands on radar. The current trajectory of this rainfall looks like it will remain mostly offshore, but will continue to monitor trends through this evening. The last couple runs of the HRRR captured the isolated showers rather well, so used it as the basis for this forecast update. 4:00PM Update... Dry weather prevails through Friday evening as surface high pressure extends out of the Great Lakes area. Clouds do linger across southeast Massachusetts, Cape Cod, and the Islands as seen on visible satellite. Shower activity has been suppressed much of today south of Block Island, Martha`s Vineyard, and Nantucket as a weak cold front sits off shore. Aloft a mid-level trough digs south with short wave energy along the eastern periphery in tandem with a weak low pressure system. It`s not out of the question an isolated shower may develop south of the Route 44 in Massachusetts and south of I-95 in Rhode Island, POPs here are generally less than 20 percent through midnight. Not good for the drought and for potential fire weather. A dry airmass combined with severe to extreme drought conditions will result in elevated fire weather concerns through this evening. Relative humidity values drop to between 25 and 35 percent across much of the interior with northwest winds 10 to 15 mph. Overnight and into early Saturday POPs will increase, slightly, between 20 and 30 percent across the islands and immediate south coast of Rhode Island and Massachusetts. The purpose of having POPs here during the overnight hours is due to a weak low passing off shore. Moving away from the coast cloud cover should thin and given fairly weak winds during the overnight hours, went with the cooler guidance of the NBM. Generally most have temperatures in the upper 50s to low 50s with the hills of western Massachusetts having temperatures in the low to mid 50s. Wouldn`t be shocked to see a few upper 40s across the higher western terrain of Franklin, Hampshire, and Hampden Counties. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Highlights... * Stunning start to the weekend with mainly dry conditions, comfortable temperatures, and low humidity. Mid-level trough exits the northeast and surface high pressure from the Great Lakes region extends into the northeast. Outside of an isolated morning shower on south shore of Rhode Island, Massachusetts, Cape Cod, and Islands we are dry! Beautiful conditions for Saturday afternoon because of the drier air mass. PWATs fall and are between 40 and 60 percent of normal for mid August. For cloud cover went with HREF, a few fair weather cumulus clouds but otherwise a mostly sunny day. Because of the drier air mass our dew points will remain lower then normal, possibly feeling more like early fall as the dew point temperatures are upper 40s to low 50s across the interior and upper 50s to low 60s at the coast. Look for high temperatures in the mid and upper 70s, a few locations that may reach 80F or 82F include the Connecticut River Valley from Hartford to Springfield. Saturday night is dry and expect clear sky cover, because of this went with the cooler of the guidance once again as radiational cooling is expected. Coolest locations will be felt in the east slope communities in the Berkshires and northwestern Worcester Hills. Else where, temperatures will fall to the mid and upper 50s. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Highlights: * Generally dry Sunday with below normal temperatures. * Unsettled early to midweek, and while not yet set in stone, potential continues for rainy conditions Tue-Thu. * Below normal temperatures continue into most of the upcoming week, with lower humidity levels continuing. Details: The latest guidance suite has not added much confidence to the forecast. Significant detail differences remain regarding the track of a low pressure moving north along the coast next week. How close this low pressure can track to southern New England will play a major role in determining how much rainfall can actually fall from this system. Some guidance sources bring a decent amount of rainfall, while others continue to have us remain dry.Most of the modeled solutions do tend to draw this low pressure closer to the coast Wednesday into Thursday, but through the Gulf of Maine. Southern New England could really use significant rainfall to help alleviate drought conditions. Unfortunately, at this time, only looking at a 15-20 percent chance of one half inch or more of rain in any 24-hour period Tuesday into Thursday. The odds are generally less than 10 percent for one inch of rain in a 24-hour period during this same portion of the week. While there is a chance for some wet weather next week, it is not looking to be very heavy overall. These details will take some time to come into better focus. Temperatures through next week are expected to be generally near normal low temperatures with below normal high temperatures, owing to increased clouds and possible showers. NBM temperatures looked reasonable. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Tonight...High confidence. Mostly VFR. Best chance for MVFR/IFR ceilings and patchy fog across southeast MA. N winds at 5 to 10 kt. Saturday...High confidence. Mostly VFR. Best chance for MVFR/IFR ceilings across southeast MA, improvement during early afternoon. N/NE winds at 5 to 10 kt. Saturday Night...High confidence. VFR. Winds are light and variable. KBOS...High confidence. KBDL...High confidence. Outlook /Sunday through Wednesday/... Sunday through Sunday Night: VFR. Monday through Monday Night: VFR. Slight chance SHRA. Tuesday through Wednesday: VFR. Breezy. Chance SHRA. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Through Saturday Night...High confidence. Mostly cool and cloudy with seas and winds below SCA thresholds. There will be periods of light showers at times, especially this evening and then on Saturday morning. Winds becoming north overnight and remain through Saturday night. Outlook /Sunday through Wednesday/... Sunday through Sunday Night: Winds less than 25 kt. Monday through Monday Night: Winds less than 25 kt. Slight chance of rain showers. Tuesday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers. Tuesday Night through Wednesday: Winds less than 25 kt. Seas up to 5 ft. Chance of rain showers. && .TIDES/COASTAL FLOODING... There is a limited threat for minor splashover due to the high astro tides, for the high tide around midnight, for those communities along the east coast of Massachusetts, this includes Cape Cod and Nantucket. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ SYNOPSIS...Belk/Gaucher NEAR TERM...Belk/Gaucher/Pederson SHORT TERM...Gaucher LONG TERM...Belk AVIATION...Belk/Gaucher MARINE...Belk/Gaucher TIDES/COASTAL FLOODING...
Area Forecast Discussion...Updated
National Weather Service Billings MT
852 PM MDT Fri Aug 12 2022 .UPDATE... Tweaked PoPs through the rest of the evening and overnight. The latest runs of the HRRR have continued to take a line of thunderstorms across the Musselshell River Valley and across into Custer County. This will likely be the southern end of the line of storms across North Central Montana. Wind gust swaths from the HRRR have been trending downward in strength, so still not expecting any widespread issues. With the strongest activity early this afternoon only saw gusts into the lower 40s, which was lower than the guidance had been showing. Reimer && .DISCUSSION... This afternoon through Sunday night... Upper level flow will remain southwesterly with a jet cutting across western and northern Montana, through the weekend. This flow and associated upper level energy will tap into a steady Monsoonal moisture fetch to bring isolated to scattered afternoon and evening showers/thunderstorms to the lower elevations. Mountain locations can expect even better chances for precipitation, and locally heavy rainfall will be possible. Will continue to keep an eye on burn areas for possible flash flooding/debris flows in this pattern, but right now storm coverage doesn`t look to warrant flood watches at this time. Temperatures will remain above average through the weekend with highs in the 90s and lows in well into the 60s. Chambers Monday through Friday... Ridging looks to remain in place through the extended period, with some degree of monsoonal moisture hanging around, although most of it will be suppressed to the south. This will result in temperatures in the upper 80s to middle 90s most days, with a slight chance of thunderstorms, mainly over the southern mountains. Humidity values from the upper teens to 20s are forecast most days, with no significant wind at this time. STP && .AVIATION... In general, VFR conditions will prevail through the period. Expect isolated to scattered shower and thunderstorm to continue into the overnight for some areas, mainly form KRPX to KMLS and north. Localized heavy rain and gusty winds are possible. Reimer && .PRELIMINARY POINT TEMP/POPS... Sat Sun Mon Tue Wed Thu Fri ----------------------------------------------------------- BIL 067/096 067/091 064/091 063/093 063/092 062/091 063/090 23/T 33/T 21/U 00/U 00/U 01/U 12/W LVM 058/094 057/091 054/091 054/093 055/092 054/091 056/090 34/T 33/T 11/U 01/U 01/U 12/W 22/T HDN 064/098 064/092 061/093 059/094 058/093 058/093 058/091 22/T 33/T 21/U 10/U 00/U 00/U 11/U MLS 069/098 069/095 064/092 063/093 063/093 062/090 061/091 12/T 32/T 21/U 10/U 00/U 00/U 01/U 4BQ 068/095 067/091 064/089 062/090 062/090 059/089 060/088 12/T 43/T 32/T 11/U 11/U 01/U 11/U BHK 065/095 066/093 063/089 060/089 060/089 059/087 059/088 02/T 42/T 22/T 11/U 11/U 00/U 11/U SHR 063/095 062/087 059/089 057/090 057/091 056/090 057/088 24/T 45/T 43/T 11/U 11/U 11/U 12/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$
Area Forecast Discussion
National Weather Service Grand Forks ND
1000 PM CDT Fri Aug 12 2022 .UPDATE... Issued at 956 PM CDT Fri Aug 12 2022 cloud cover remains the issue in terms of updates tonight. Clearing area is slowly progressing south thru the northern Red Red River valley and far NW MN. Cloud bases have risen in most areas, exception being Bemidji area where IFR clouds remain, and looks like IFR lower clouds are trying to push back west. So overall idea of a mostly cloudy, but some clearing pockets remain ok for messaging overnight. Some fog potential as well, but where remains uncertain. Earlier it was indicating more central ND. UPDATE Issued at 652 PM CDT Fri Aug 12 2022 Tonight forecast challenges will be clouds and fog development. HRRR and CONSHORT indicate substantial fog development in central ND into DVL basin, if area clears of clouds. Rest of the area seeing clouds, some lower IFR/MVFR Devils Lake to Bemidji, with some clearing far northern RRV to Warroad. This mess of sky cover will be a problem tonight with low confidence on how cloud cover turns out overnight. Dew pts are high in the mid 60s and winds light so lots of questions about how much clearing will occur. Did add fog to the forecast using vsbys forecast from CONSHORT and will need to extend cloud cover area longer. && .SHORT TERM...(This afternoon through Saturday night) Issued at 333 PM CDT Fri Aug 12 2022 Minimal sensible weather impacts are anticipated through Saturday night. The stationary front is lingering near our southern CWA and north of this low stratus is lingering. This did act to supress high temperatures and beside aviation impacts it would mainly influence radiational cooling/overnight lows due to insulation if it lingers. This cloud layer hasn`t been handled well, but there should be a trend with drier air arriving as surface ridging builds southeast. Saturday-Saturday night: Most of Saturday should remain dry and mild though clouds will again play a role in potential highs (70s vs lower 80s). By Saturday night a weak shortwave and associated upper jet streak may bring showers and weaker thunderstorms back into the region from the northwest with most activity shown by CAMs to develop near a surface trough in proximity of the Devils Lake Basin. There isn`t a lot of movement eastward so where it develops, so we eastern extent of this activity Saturday night is more uncertain. Instability is limited so besides light rain (current consensus keeps amounts 0.25" or less). .LONG TERM...(Sunday through Friday) Issued at 333 PM CDT Fri Aug 12 2022 Saturday through Tuesday: We remain on the back-half of the 500mb ridge setup over the Central Plains as the low pressure system regenerates over the Great Lakes. Saturday remains in North to Northeast flow over eastern North Dakota and northwestern Minnesota. Sunday transitions into a Southerly flow that persists through Tuesday. High temperatures are going to remain fairly consistent in the mid 80`s for this period. The greatest chance (45%) for rain is going to be Sunday afternoon over the Devils Lake basin. This is due to a mid-level shortwave riding the ridge over the northern plains. Accumulation up to half an inch of precipitation is expected to occur with this event. Tuesday through Thursday: Tuesday, another mid-level shortwave moves itself over Ontario. Temperatures will drop slightly into the mid 70`s on Tuesday. This temperature trend will remain until Thursday as the shortwave helps form an area of low pressure in the Northeastern United States. Wednesday into Thursday the winds gradually shift from a Southerly flow into a Northerly flow. There`s a slight chance of precipitation during this transition but POPs remain under 30% Wednesday into Thursday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 652 PM CDT Fri Aug 12 2022 In comparision to the last several days, a much more tricky aviation forecast. Tonight clouds and fog development hold the key. Light winds in central ND and if area can clear then fog formation is most likely there into DVL basin. Low clouds may hang on much of the night Grand Forks to Bemidji and may spread south. So for the overnight low confidence in how cloud bases and vsbys will be thru 12z Sat. Would expect any morning clouds/fog to burn off and scatter out daytime Saturday. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. $$ UPDATE...Riddle SHORT TERM...DJR LONG TERM...MM/Perroux AVIATION...Riddle
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1012 PM EDT Fri Aug 12 2022 .SYNOPSIS... Canadian high pressure will bring cooler and drier air to the region through the weekend. Gradually increasing moisture is expected next week. Other than a brief warm-up early next week, temperatures are and expected to remain cooler than normal for much of the week. && .NEAR TERM /THROUGH SATURDAY/... As of 1000 PM EDT Friday: There is a small line of tstms look to be weakening as they track southwestward across Newberry County. They might skirt parts of Laurens and Greenwood counties, but otherwise, just a few stray showers are expected for the rest of the evening and overnight. Plenty of mid clouds or high-based stratocu are expanding along the Blue Ridge escarpment and Piedmont thanks to easterly flow. But cooler/drier is filtering in from the north, and so we should see slightly below normal min temps, despite the clouds. Fog is unlikely except maybe in the normally more foggy locations. Lows should end up about 5 degrees below normal. Even the low level moisture moves out on Saturday and cooler and drier high pressure finally builds more fully into the area. That said, there may be enough moisture and weak instability for isolated showers over the Smokies. Highs will be about 5 degrees below normal with dew points dropping into the 50s across much of the area leading to a refreshingly low humidity day. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of 235 PM EDT Friday: the short-term fcst picks up at 00z on Sunday with extensive upper ridging still dominating the western 2/3 of the CONUS while fairly deep/broad upper trofing remains over the mid-Atlantic states. Over the next couple of days, the trof axis is expected to lift northeast of New England, yet upper trofing will remain largely in place across the region thru the end of the period late Monday. At the sfc, the center of broad high pressure will be translating eastward and over the Atlantic Coast as the period begins. By late Sunday, another cold front will approach our fcst area from the NW and bring an increase in moisture with it. The frontal bndy is not expected to actually move thru our CWA until late Monday as the period is ending. As for the sensible fcst, both PoPs and QPF have been increased late Sunday thru the end of the period late Monday. However, QPF is still not expected to be excessive and should not cause any significant hydro issues. Temps should remain just below normal both Sunday and Monday. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 225 PM EDT Friday: the extended fcst picks up at 00z on Tuesday with broad upper trofing still in place over the Eastern CONUS and extensive ridging to the west. Over the next 24 to 48 hrs, the upper trof is expected to morph into a large, closed upper low and then expand further westward. By the end of the period late next week, the trof is expected to cover roughly the eastern half of the CONUS. At the sfc, a weak cold front will be moving east of our CWA as the period begins. In the front`s wake, weak high pressure tries to spread back into the area from the north, however the latest long-range guidance has it making less southward progress into our area. At the same time, the synoptic pattern is looking more chaotic/uncertain with the operational models trying to develop multiple sfc lows over the Southeast and then move them eastward and off the SE Coast. Overall, the pattern is trending more active with the above-mentioned high not exerting as much influence over our area with solid-chance PoPs each day thru day 7. Temps are also trending cooler thru most of the period, with highs expected to start out about a category below normal on Tues, and remain 1 to 2 categories below normal thru day 7. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... At KCLT and elsewhere: Isolated showers (and possibly a tstm or two) will linger across mainly the Upstate and NE GA this evening. The HRRR continues to show showers continuing in these areas overnight, as easterly flow lifts some moisture. However, the coverage looks to isolated to warrant any shower mention in the TAFs. Overall, the clouds are expected to be VFR, but some MVFR or lower cigs will be possible in the mountains. Will mention some MVFR cigs at KAVL for early Saturday morning. Drier air works into the area Saturday, with just high-based cu expected at all TAF sites. Winds will be NE thru the period at the Piedmont sites. At KAVL, winds will favor a N direction until around 14z Saturday, then toggle to S/SE. Outlook: Moisture slowly returns Sunday into early next week. Expect diurnal convective chances to slowly increase as well. Fog and low stratus may develop each morning in the mtn valleys. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...ARK/RWH SHORT TERM...JPT LONG TERM...JPT AVIATION...ARK
...Updated Aviation Forecast Discussion...

.DISCUSSION... Issued at 255 PM CDT Fri Aug 12 2022 Key Messages: - Hot Saturday, warm to hot Sunday, a little cooler for next week. - Rain chances Sunday night into Tuesday. Quiet across the region this afternoon as mid to upper level ridging remained firmly in control. Decent southerly flow associated with surface low pressure over the Dakotas and plenty of sunshine helped to keep us rather warm, with temperatures as of 3 PM in the 90s for most of the area. Also of note at the surface was a cold front stretching southwestward across SD that will edge into northeast NE by this evening. Many CAMs suggest potential for some showers and perhaps an isolated storm or 2 along the boundary as it moves through into Saturday morning. Still a few questions on how far south any associated precip makes it, with the HRRR being the most aggressive and indicating at least some potential as far south as I- 80. However, anything that develops looks to remain quite spotty and not amount to much. Ridging stays in place Saturday and Sunday keeping us rather quiet, but warm to hot. Despite northerly flow behind the front on Saturday, guidance still suggests widespread 90s with a few spots perhaps making a run at 100. In addition, there will be a touch more humidity, as dewpoints get into the mid to upper 60s for many, which will lead to heat index values topping 100 for many. Sunday should be a touch cooler with persistent easterly to northeasterly surface flow, though still expecting highs in the mid 80s to mid 90s, warmest in southeast NE. The eastern periphery of the ridge starts to break down by Sunday evening as various bits of shortwave energy round the ridge and slide through the forecast area. This will bring persistent rain chances to the area Sunday night into Tuesday. Instability looks to be lacking, so wouldn`t expect much in the way of thunderstorms dumping heavy rainfall, but even a persistent light rain would likely be welcome for most. While questions remain on exact placement of the "heaviest" rainfall, it`s looking like a fairly good bet a majority of the forecast area sees at least some precip. Interestingly, the recently wet-biased GEFS guidance is much drier than EPS guidance, with the 12.12Z GEFS showing a 10-30% chance for 0.5" across the area through Tuesday and the 12.12Z EPS showing a 50- 80% chance. For what it`s worth, current forecast is for 0.25" to 0.75" for many, with some spots getting over 1". Again, still quite a bit of spread in guidance, but potential is there for some widespread rain for a change. In addition to the rain chances, we`ll see some relief from the heat, with temperatures through next week progged to top out in the 80s each day. Areas that receive more rain on Monday/Tuesday could also stay in the 70s those days. May see some additional spotty rain chances through the remainder of the week as more bits of shortwave energy slide through, but spread in guidance remains quite large to narrow it down to any one favored timeframe. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 544 PM CDT Fri Aug 12 2022 LLWS threat will increase at all terminals after midnight ahead of cold front/wind shift. Otherwise, VFR conditions expected to prevail. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...CA AVIATION...DEE
Area Forecast Discussion
National Weather Service San Diego CA
900 PM PDT Fri Aug 12 2022 .SYNOPSIS... Heat and humidity will continue into the weekend, while increasing monsoonal moisture fuels more shower and thunderstorm development, mainly over the mountains and deserts. Moisture levels will decrease slightly early next week with less thunderstorm coverage expected then. No major changes to our warm and humid, monsoon pattern is likely through next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Moisture, pumped high into the atmosphere from an active monsoon day, remained over SoCal this evening, noticeably punctuating our sunset. There was still some active thunderstorms at 9 PM PDT near and just north of Twentynine Palms. This will need to be watched if it starts to expand westward. Our 00Z Miramar sounding continued to moisten throughout the column, recording 1.42 inch. A shallow dry layer remained below 5K FT. The sfc pressure gradients were weak, and wind reports mostly light. It was quite warm inland across the I.E. and the deserts where temperatures climbed above the century mark, along with noticeable humidity. A Heat Advisory remains in effect for the I.E. tomorrow. Strong thunderstorms were concentrated along the east slope of the San Diego Mts, and locally into the deserts late this afternoon. Biggest Radar estimated storm totals were over the San Diego County deserts, ranging from 1.5 to locally 3 inches. Flash flooding likely occurred in some of these remote desert areas near the Fish Creek Wash. A weak easterly wave has arrived across NW MX and SoCal and likely contributed to the strong thunderstorm development. More are marching slowly westward across western AZ this evening and will only contribute to the available moisture across the area tomorrow. Saturday should be an active thunderstorm day if our WRF and HRRR models are correct, and with PW values near two inches, local flash flooding will be a concern. High pressure over the West will be shifting around over the next week or so, but remain far enough north to make us eligible for bouts of monsoonal moisture through at least next week. A look at the ensemble clusters of the two main global models show enough drying by some of the clusters, to expect a decrease in the afternoon shwr/t-storm chances, but little confidence it will end. So low POPS remain in the forecast each afternoon through next week, especially over the mountains. It will remain seasonally warm and humid now that sea surface temperatures are in the upper 60s and 70s over a good chunk of the CA Bight. && .AVIATION... 130310Z...Coast/Valleys...SCT-BKN clouds at/above 10,000-20,000 feet MSL with unrestricted vis will prevail today and tonight. Slight chance of intermittent SCT-BKN cigs tonight 600-1000 ft MSL with varying visibility near the coast 13-16Z Saturday morning. Mountains/Deserts...SCT-BKN clouds at/above 10,000 feet MSL with unrestricted vis will generally prevail through tonight. Slight chc for ISO-SCT TSRA between 05-09z Sat as outflow from storms over eastern Riverside/San Bernardino Counties enters the area. Bases would be around 8,000-10,000 feet MSL and tops to 35,000 feet MSL with strong up/downdrafts, gusty winds, and downpours with any storms. && .MARINE... No hazardous marine weather is expected through Wednesday. && .BEACHES... High tides to around 7 feet again this evening may lead to minor tidal overflow of beaches and exposed parking lots around the times of the evening high tides. Surf will remain low, so no significant damage is expected. && .SKYWARN... Skywarn activation may be needed on Saturday. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Heat Advisory until 8 PM PDT Saturday for San Bernardino and Riverside County Valleys-The Inland Empire. PZ...None. && $$ PUBLIC...10 AVIATION/MARINE/BEACHES...Adams
For frequently asked questions about the Area Forecast Discussion
Area Forecast Discussion
National Weather Service Las Vegas NV
235 PM PDT Fri Aug 12 2022 .SYNOPSIS...Moist monsoonal flow will remain in place through next week leading to the potential for thunderstorms with heavy rain over the eastern Mojave Desert and southern Great Basin. Further west across the Sierra and Western Mojave Desert, generally dry weather expected over the weekend with increasing storm chances next week. && .SHORT TERM...through Sunday. Thunderstorms got going a little early today. There was a circulation over Lincoln and northern Clark Counties and a also one lifting up from southwest Arizona in addition to the surface heating and the moist and unstable air mass that remains in place over southern Nevada, northwest Arizona and far southeast California. Boundary interaction will come into play with additional storm development through the late afternoon and early evening. The latest HRRR indicates the potential for thunderstorms converging over the Las Vegas area this afternoon then propagating southward this evening. Storms should dissipate late this evening and overnight then conditions Saturday look quite similar to today, though any storm induced circulations are a wildcard. The Flash Flood Watch was extended through Saturday evening for zones where it is currently in effect. We should see similar thunderstorm development with scattered to numerous slow-moving storms with the potential heavy rain. There is not much change in expectation with storm development through Sunday, so plan on more of the through the weekend. .LONG TERM...Monday through Friday. As we head into next week, the monsoon shows little sign of slowing down with rich moisture locked in place across the Mojave Desert and southern Great Basin. Meanwhile, high pressure builds into the northern Great Basin which could shift the steering flow to a more north or northeasterly direction for a few days, a favorable pattern for thunderstorm complexes moving into the lower deserts. Aside from the daily storm chances, temperatures will remain at or below normal through the period, with the greatest departures from normal across the eastern Mojave Desert where deeper monsoonal moisture will be hanging around. && .AVIATION...For Harry Reid...Scattered thunderstorms are forecast for the area once again this afternoon. The best chances of seeing direct impacts on the field are between 22Z and 02Z, with primary impacts being gusty outflow winds, brief heavy rainfall, and lightning. Outside of thunderstorm activity, light southerly winds and skies FEW-SCT AOA 10kft are expected. Little change in the overall pattern is expected over the weekend keeping the chance of afternoon and evening storms in place through at least Sunday. For the rest of southern Nevada, northwest Arizona and southeast California...Scattered thunderstorms are expected at all TAF sites today with the exception of KBIH. The best chance of seeing storms will be mainly after 22Z and any storms will be capable of producing gusty winds, brief heavy rain and lightning. Outside of thunderstorm activity expect light winds favoring typical diurnal variations and FEW-SCT skies AOA 10kft. Little change in the overall pattern is expected over the weekend maintaining the threat of afternoon and evening storms through at least Sunday. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ SHORT TERM...Adair LONG TERM...Outler AVIATION...Planz For more forecast information...see us on our webpage: or follow us on Facebook and Twitter