Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/02/19

Area Forecast Discussion...Updated
National Weather Service Billings MT
840 PM MDT Sun Sep 1 2019 .UPDATE... Strong convection from late this afternoon and very early this evening, has left the state. There were some lingering clouds over the far southeast, indicative of some instability left over from the convection. Shortwave energy has pushed east, but another wave was in western Montana and progged to slide across the northern half of the state overnight. Models were not very bullish on QPF, especially some of the high resolution ones, but can see the legitimacy of keeping some PoPs over parts of southeast Montana tonight as mid level warm advection interacts with a fairly weak low level jet. Have fine tuned the PoPs to account for less of a risk of convection and confined it mostly to the far southeast. HRRR still advertising the potential for some fog over eastern parts of Fallon and Carter counties Monday morning, so will leave that in. TWH && .SHORT TERM...valid for Mon and Tue... Did not make any large changes to the previous forecast. An upper ridge remains over the area tonight, with an inverted surface trough over the eastern zones. A low-level jet develops over the E this evening and shifts E overnight. MLCAPES will be around 1000 j/kg this evening in the E per SREF with effective Bulk Shear greater than 40 kt. The high CAPES and shear shift E of the area late tonight/early Monday. PWAT`s will also be over an inch in the E. Kept chance PoPs in the E this evening, and shifted PoPs into just KBHK area overnight per HREF QPF. Will keep mention of small hail/gusty winds with storms through the night based on the above. RH recoveries looked a little better than they did yesterday and will range from the 40s W to the 80s E. After checking RAP soundings and HRRR, cannot rule out patchy fog and stratus moving into the KBHK and Ekalaka areas again late tonight. The ECMWF ensembles showed uncertainty with the synoptic pattern Monday through Tuesday, while GEFS spaghetti plots had spread Mon. night through Tue. night. Thus timing, placement and strength of features was a bit uncertain. In general, expect a weak trough to move through the region on Mon. into Mon. evening, with ridging rebuilding Tue. and Tue. night. A second trough may affect the area late Tue. night. A cold front will drop S through the area Mon. afternoon. It will be hot and dry on Mon. with RH`s in the teens from KBIL-KSHR W...and 20s to 40s E of this line. Winds still look to become gusty from the NW behind the front Mon. afternoon and will continue to be strong in the evening. Raised PoPs a bit Mon. evening with frontogenesis and moisture behind the front. Shifted PoPs SE and decreased them overnight. Did not see any CAPE Mon. night, so kept only a mention of thunder. RH`s will come up during the evening hours. Since the fuels are not critical, will continue to just headline the FWF with expected conditions. Tuesday will be cooler with higher humidities. No precip. expected, except a slight chance in the Beartooths/Absarokas. It will be mostly dry Tue. night. Arthur .LONG TERM...valid for Wed...Thu...Fri...Sat...Sun... Wednesday and Thursday will generally warm and dry as a high pressure builds back into the area. Highs will be in the upper 80s to lower 90s. Friday will see flow aloft turn southwesterly as a another wave moves into the Northern Rockies. Afternoon showers and thunderstorms will develop as the energy and moisture move into the area. For the weekend and into early next week the pattern will turn towards a more unsettled and troughy pattern. This will result in temperatures remaining generally in the mid to upper 70s. Chances mainly in the afternoon and evening each day for showers and thunderstorms remain. Reimer && .AVIATION... VFR conditions will prevail through the period with passing mid and high clouds. Overnight showers or thunderstorms are possible east of a line from KMLS to 4BQ, but this activity will be isolated to widely scattered. Patchy morning fog is also possible around KBHK Monday, which would briefly limit conditions to MVFR locally. TWH && .PRELIMINARY POINT TEMP/POPS... Mon Tue Wed Thu Fri Sat Sun ----------------------------------------------------------- BIL 061/094 057/084 058/092 059/087 058/079 054/078 054/078 00/U 30/U 10/U 12/T 33/T 31/B 24/T LVM 052/090 048/086 051/090 052/085 050/079 048/079 048/075 00/N 20/U 10/U 14/T 64/T 32/T 35/T HDN 059/092 054/082 056/091 057/087 057/078 052/077 052/079 00/U 30/U 10/U 11/U 33/T 32/T 23/T MLS 062/089 054/077 055/088 057/085 056/075 051/073 051/075 20/N 20/U 10/U 11/U 22/T 32/W 23/T 4BQ 061/091 054/078 055/089 056/086 056/076 051/072 050/075 10/U 20/U 00/U 11/U 23/T 42/T 23/T BHK 058/087 052/075 050/085 054/083 052/073 047/069 046/071 31/B 10/U 00/U 10/U 22/T 42/T 23/T SHR 058/093 053/082 055/090 055/087 055/078 050/076 050/079 00/U 31/U 10/U 12/T 43/T 42/T 34/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$
Area Forecast Discussion
National Weather Service State College PA
1016 PM EDT Sun Sep 1 2019 .SYNOPSIS... Moist air is flowing into the area ahead of a cold front which will push southeast through the area late Monday. A more significant cold front will arrive Wednesday. High pressure is likely to build southeast into the region late next week, as Hurricane Dorian tracks along but just off the Mid Atlantic coast. && .NEAR TERM /UNTIL 9 AM MONDAY MORNING/... First line of storms is much weaker now, but some heavy rain concerns still exist with multiple clusters of moderate rain with small pockets of heavy rain. Recent runs of the RAP and HRRR have begun to move the precip along steadily, with the heaviest associated with the first line. One bow echo starting to form a county or two to our west, but some stabilization due to light rain and loss of heating may be occurring before that feature can move over the land in front of it. Wettest location in the CWA is the NW where the precip will likely be heaviest over the next 2-3 hrs. Will continue to monitor for minor flooding problems, but FFG remains fairly high. Prev... Very potent shortwave trough moving through OH seen on WV imagery is driving clusters of thunderstorms, many of them have been severe over Central OH and into ern OH, now. Earlier storms have had the help of the daytime heating, but with sunset, that is obviously not the only reason these things are still going strong (and perhaps getting worse). Have only made tweaks to the near term PoPs/Wx/QPF, but may have to add mentions of SVR winds, too, for the western zones. May get busy before too long. Might have a threat for flooding, too, as these storms would be passing over ground wettened earlier today in our NWrn counties. Prev... Two persistent areas of showers have been maintained from the late morning through mid afternoon hours, the first over the Northwest Mountains and the other from the South Central Mountains lifting into the Ridge and Valley Region. It has been a wet day in both of these locations with some areas seeing in excess of one half inch of rainfall. Elsewhere, skies have been mostly cloudy with very little in the way of rain just yet. That will be changing tonight, as the deepest moisture and forcing coincide over Central PA. Mid level shortwave and associated plume of anomalous PW and a slow moving 850 mb jet traverse the area from late this evening through 12z. This will keep the highest POPS of near 100pct across the northwest mountains under axis of low level jet, with the lowest chance across the southeast counties. Already seeing some brief mdt-hvy downpours in some of the southern activity, but cell motions so far have precluded any flooding concerns (that and recent dryness). Still, as moisture flux continues and additional instability is added to the mix, there is the potential for localized one inch plus amounts (and some CAM solutions show in excess of 2-3" in spots). Still believe the threat for flooding is quite low given recent dry weather and high FFG numbers. Mins tonight will range from the upper 50s north to the mid 60s south. && .SHORT TERM /9 AM MONDAY MORNING THROUGH 6 PM MONDAY/... Best forcing for showers on Monday remains during the morning as aforementioned shortwave and boundary layer jet at 12z push off to the east by afternoon as surface warm front lifts northward across the region. Brightening skies are anticipated by afternoon, as we break into the warm sector. Scattered afternoon thunderstorms will be possible in the increasingly unstable air mass ahead of a weak cold front pressing southeast from the Grt Lks. Moderate instability progged by both the GEFS and HREFV2, combined with decent mid level flow has put parts of central and eastern PA in MRGL Day 2 SPC Outlook on Monday. Maxes will range from the lower 70s north to the lower 80s southeast. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... Made a few small changes to this part of the package. Main thing was to go with dry conditions next Sunday, as wave on the cold front is likely to stay just south of the area. Can change this in the coming days if needed. Other change was to push showers a tad further northwest later Thursday into Friday, as moisture from the southeast could be pulled across southeast PA. First cold front moves east of the area by Tuesday morning. Weak high pressure builds into the area with dry conditions for Tuesday. A stronger cold front moves into the area from the upper Great Lakes, as a strong upper level jet lifts northeast across eastern Canada. Will have to look this over as we get closer to Wednesday, as the combination of trailing jet max and timing of the front could lead a a few strong storms. Cooler air at low levels is advected from the northeast on Thursday, as high pressure builds into the area. Temperatures will run a few degrees below normal. Another strong cold front moves across the area the first part of next weekend, with limited moisture. Another large high pressure builds into area behind this cold front. Temperatures behind this front will be colder, upwards of 5 to 10 degrees below normal. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... Widespread restrictions are expected overnight, as ceilings are expected to gradually drop to IFR. A more robust area of showers will push into the area overnight as well. The breeze will gradually veer from southeasterly to a more southerly direction. Unsettled weather will persist into Monday, as a weak cold front crosses the area. Ceilings will slowly improve, but some restrictions could persist through the day. Thunder is possible by afternoon, especially across the south and east. High pressure will provide improved conditions for Tuesday, before another cold front approaches on Wednesday. .Outlook... Mon...Reduced cigs/vsbys in scattered SHRA/TSRA. Tue...AM low cigs/fog possible, then becoming VFR. Wed...Reductions possible by aftn in scattered SHRA/TSRA. Thu-Fri...Generally VFR, although showers could sneak into the southeast. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Dangelo/DeVoir NEAR TERM...Dangelo/DeVoir SHORT TERM...DeVoir/Fitzgerald LONG TERM...Martin AVIATION...Evanego
Area Forecast Discussion
National Weather Service San Diego CA
100 PM PDT Sun Sep 1 2019 .SYNOPSIS... High pressure aloft will continue very warm conditions most of this week. Monsoonal flow and warm coastal waters will result in generally humid conditions as well, and the monsoonal flow will bring chances of mainly afternoon and evening thunderstorms over the mountains and deserts, especially Monday through Wednesday when a few storms could drift west of the mountains. Night and morning low clouds will mainly be less extensive most of the rest of the week. A trough of low pressure off the coast will likely bring drier air and some cooling though also an increase in the marine layer low clouds next weekend. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Stratus was still widespread over the coastal waters and beaches but have cleared over land. Some mid-high clouds from the southeast were drifting over land as well. Cumulus was forming over the mountain crests, but no thunderstorms had formed yet. Models do not have much explicit precipitation for this afternoon, with some HRRR runs even keeping us dry, but a few thunderstorms should form this afternoon, mainly over the mountains and desert slopes in San Diego and Riverside County where SPC mesoanalysis shows some CAPE over 1000 J/kg. The upper high will continue roughly over the Four-Corners region through Thu or Fri, with a weak inverted trough moving west to our south Monday. Most ensemble solutions show Tropical Storm Juliette staying well to the south, except for a few GEFS solutions showing remnants approaching from the south next weekend when a Pacific trough moves into California from the west. NHC guidance keeps it south of the Tropic of Cancer through Friday, and this should have little or no impact here. What we will have is high amounts of moisture (RH > 70%) in the 700-500 MB layer especially Mon/Tue and moderate amounts of moisture (RH > 50% at times) even below that, with some decreases Wed, especially below 700 MB. Total precipitable water could exceed 2 inches both along the coast and in the lower deserts. Instability will be sufficient for thunderstorm development, with surface-based CAPE over 1000 J/kg at times. With all the moisture and instability, there is a concern of local flash flooding from heavier rains either Monday or Tuesday. Mid-level winds will be moderate, 10-20 knots, which won`t be enough to inhibit heavy rains. A few storms could drift west of the mountains Monday or Tuesday, but this mostly will be confined to the Elsinore Convergence Zone, especially since any upper level trigger would appear to weak to spark the moderate amounts of elevated CAPE in the 700-500 MB layer. Some thunderstorm chances will remain through Friday but should diminish by Saturday as the trough moving into California will bring drier southwest flow. The marine layer stratus, after its stronghold this morning, should be less notable Monday and Tuesday due to the moisture aloft increasing the long wave radiation reflected back to the surface. Temperatures should decrease slightly Monday, though only by a few degrees, and the heat advisory for the Inland Empire and excessive heat warning for the high deserts will be allowed to expire tonight. Some renewed warming west of the mountains Tue/Wed may be enough to require an excessive heat advisory again in the Inland Empire as a lot of areas will likely be over 100. && .AVIATION... 012000Z...Coast...VFR conditions should prevail at the terminals through midnight tonight, however patchy stratus will linger on the beaches and may generate brief periods of BKN CIGS at any of the coastal terminals. SCT-BKN high clouds AOA 15,000 FT MSL and a decrease in onshore flow will help suppress stratus coverage tonight. Leaning toward prevailing VFR at the terminals overnight, but periods of BKN CIGS with bases 400-900 FT MSL cannot be ruled out. CIGS most likely in coastal San Diego County, and between 10- 15Z. Mountains/Deserts...Scattered Cu over the mtns this PM with bases near 10,000 FT MSL. Slight chance of SHRA/TSRA through 02Z, mainly for SD and RIV County mtns. Otherwise, SCT-BKN clouds AOA 15,000 FT MSL through Monday AM. && .MARINE... No hazardous marine conditions expected through Friday. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Excessive Heat Warning until 8 PM PDT this evening for Apple and Lucerne Valleys. Heat Advisory until 8 PM PDT this evening for San Bernardino and Riverside County Valleys-The Inland Empire. PZ...NONE. && $$ PUBLIC...Maxwell AVIATION/MARINE...Rodriguez