Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/07/24


Area Forecast Discussion
National Weather Service Indianapolis IN
912 PM EDT Fri Sep 6 2024 .KEY MESSAGES... - Becoming clear and cooler tonight, sunny and cool on Saturday - Potential for sub-40 degree temperatures in rural areas Saturday night, mainly north of I-70 && .FORECAST UPDATE... Issued at 912 PM EDT Fri Sep 6 2024 Subsidence in the wake of a cold front along, a drying column per H- Res soundings, dew points in the middle 40s to lower 50s advecting in from the north all support clearing skies overnight. IR satellite and surface obs were already showing clear skies north of a Terre Haute to Noblesville line. Although, winds will stay up tonight preventing ideal radiation cooling, cold advection will be at play and should allow chilly temperatures to bottom out in the middle 40s to the lower 50s or 10 plus degrees below normal. && .SHORT TERM (This evening through Saturday)... Issued at 244 PM EDT Fri Sep 6 2024 Synopsis: Surface analysis this morning shows a cold front stretching from Columbus OH, to south of Columbus IN and then southwest to western KY. A few light rain showers were found in the wake of the front over central Indiana. Precipitation was very isolated in coverage. Winds in the wake of the front were front the north, ushering cooler and less humid air into Central Indiana. Aloft, a large ridge of high pressure was found across the western CONUS, while a deep upper low was found over Ontario with a trough axis pivoting across the Great Lakes and IL/IN/OH. GOES16 shows an area of cloud cover in the wake of the front across central Indiana drifting southeast, while the rest of the state was essentially partly cloudy. Late this afternoon and Tonight - Clouds associated with the departing cold front will slowly progress south and east across Central Indiana this afternoon and early evening. South of these clouds, temperatures reaching the lower 80s appear warm enough to generate a few showers and thunderstorms late this afternoon. HRRR continues to suggest isolated to scattered shower or storm development late this afternoon across points south and east of Indianapolis. Forecast soundings and ACARS suggest some limited but available CAPE this afternoon ahead of the front. Thus as we reach peak heating hours, a few isolated showers and storms across the SE parts of the forecast area cannot be ruled out. By 00Z-02Z HRRR suggests any precipitation will have drifted east and exited the forecast area. Clouds upstream of this cloud band appear quite diurnal in nature. This will suggest a quick deterioration of cloud cover this evening. Forecast soundings trend toward a dry column overnight as subsidence is expected to build. Thus will trend sky cover overnight toward mostly clear skies. A moderate pressure gradient in place should allow for a sustained winds of 5-10 mph overnight, prevent full radiational cooling. Lows tonight should fall to the upper 40s and lower 50s. Saturday - The upper low will is expected to be over eastern Ontario on Saturday while strong ridging remains in place over the Rockies. This will result in strong NW flow across Indiana along with strong subsidence. Mid levels show strong drying through the day spreading from the NW across Central Indiana. Forecast soundings and time heights also show a very dry column. Thus a mostly sunny day will be expected as surface high pressure builds across the area from the north. Strong cold air advection will be in play, allowing 850mb temps to fall to 4C by 12Z Sat. This will allow highs in Saturday to only reach the upper 60s to near 70 which will be a true taste of fall temperatures. && .LONG TERM (Saturday night through Friday)... Issued at 244 PM EDT Fri Sep 6 2024 Expect quiet weather conditions through the long term period as surface high pressure remains dominant across the Ohio Valley. The main focus in the extended will be anomalously cold overnight lows this weekend and worsening drought conditions into next week. Upper troughing will persist through the weekend helping to keep temperatures below normal. Widespread lows in the low-mid 40s are likely Saturday night as surface high pressure continues to build in providing optimal radiational cooling conditions. Given the good setup for radiational cooling and the very dry airmass in place, temperatures usually end up on the lowest end of model guidance. This may allow for rural areas across the north to fall into the upper 30s. Frost is unlikely, but there could be a few highly localized areas that drop into the mid 30s which could damage highly sensitive vegetation. The aforementioned upper trough should begin to shift east by early next week with upper ridging building in. At the surface, high pressure will continue to remain dominant which will allow dry weather to continue. This extended dry stretch will likely lead to worsening drought conditions and an expansion in drought coverage. There is a weak signal for low rain chances late next weekend into the following week, but beneficial precipitation looks unlikely in the next 7-10 days. Expect temperatures to quickly warm up as the upper ridge builds across the region. Widespread highs in the mid- upper 80s are likely by the middle of next week. && .AVIATION (00Z TAF Issuance)... Issued at 621 PM EDT Fri Sep 6 2024 Impacts: - None Discussion: Would not rule out a brief shower this evening as an upper trough pivots across the Great Lakes. A strengthening low pressure gradient will result in breezy northwest winds with gusts to 20+ plus mph this evening. More gusts to 20 knots or more are expected Saturday as the atmosphere mixes down. Otherwise, look for VFR conditions with some lingering evening stratocu and possibly scattered fair weather diurnal cu Saturday afternoon. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...MK SHORT TERM...Puma LONG TERM...Melo AVIATION...MK
Area Forecast Discussion
National Weather Service Marquette MI
721 PM EDT Fri Sep 6 2024 .KEY MESSAGES... - High swim risk through Saturday for the Lake Superior beaches of Marquette and Alger counties. - Light lake effect rainfall continues through at least Saturday morning. - Drier and warmer weather returns next week with increasing ridging from the west. && .SHORT TERM /THROUGH TONIGHT/... Issued at 228 PM EDT Fri Sep 6 2024 Water vapor imagery shows a midlevel trough extending from near Hudson Bay to the Great Lakes, with a surface low moving into Quebec per RAP analyses. As a result, the UP remains under chilly northerly flow with 850mb temperatures already analyzed at around 3-4C. With Lake Superior surface temperatures at around 11-18C, delta-Ts are high enough to keep the lake effect machine going. Most of the UP remains under a blanket of low lake clouds, with light lake effect rain showers/drizzle continuing mainly across the central and eastern UP. Temperatures, meanwhile, are climbing into the low to mid 50s across most of the UP so far, and may be able to peak closer to 60F in Menominee county. However, some spots closer to Superior are struggling to get out of the 40s. Under cloudy skies, temperatures shouldn`t budge much more the rest of the afternoon. Winds mainly out of the north remain gusty, particularly across the eastern UP, with gusts up to 20-25mph common. Tonight, 850mb temperatures continue to fall back to around 0-2C. This will support lingering lake effect clouds/showers across the eastern half of the UP, while cloud cover slowly erodes to the west as flow turns more anticyclonic. The main forecast concern for tonight remains the potential for frost. Our chilly airmass would support widespread overnight lows in the 30s, with the lower/mid 40s more common closer to the lakeshores. Where skies can clear, and particularly in the typically cooler spots in the interior-western UP, temperatures may fall into the mid 30s, with a slight chance (20%) for even cooler values closer to the freezing point. If cloud cover persists, however, temperatures even out west may come in slightly warmer and limit our frost potential. Therefore, will continue to shy away from any headlines. && .LONG TERM /SATURDAY THROUGH FRIDAY/... Issued at 339 PM EDT Fri Sep 6 2024 Starting on Saturday, the mid level troughing over the Great Lakes gradually shifts east developing into a closed low. At the same time, the UP will be straddled between a deepening sfc low to the east and high pressure to the west. This continues the cold northerly flow setup over the region. Lake Superior temps are currently around 15-19C and with 850 mb temps starting the day between 2C to -2C (colder east), delta-Ts will still be supportive for lake effect showers. As a warmer and drier airmass works its way in, these gradually diminish. Colder than normal temps are expected under the cool north flow, ares in the north-central and northeast will only peak in the mid 50s underneath partly cloudy skies that linger for much of the day. Where lake effect cloud cover scatters out earlier, warmer temps peak near 60. The UP turns dry Saturday night as lows settle into the upper 30s to upper 40s, warmer near Lake Superior. Although cool conditions are not ideal for a beach day, high swim risk for dangerous rip currents continues at Marquette County beaches through Saturday afternoon and sunset at Alger County Beaches thanks to persistent north winds. While mostly dry weather is likely to persist on Sunday, very low chances (15-20%) for light showers accompany a weak sfc trough settling southeast into the Upper Great Lakes. It has support from the left exit region of an upper level jet, cyclonic flow, and weak isentropic ascent. The limited forcing and spotty moisture noted in the model soundings leave low confidence in precip during this period. That said, partly cloudy skies likely accompany this disturbance Saturday night into Sunday. Otherwise, highs on Sunday warm near normal in the upper 60s to mid 70s, cooler in the east. Lows Sunday night are expected in the mid 40s to mid 50s. Next week, remains mainly dry as mid level ridging shifts east from south central Canada/Northern Plains to the Great Lakes. This sets up a blocking sfc high over the east to eventually northeast CONUS that prevents much of any precip from making it into our area. While there is a very low chance ~15% for showers accompanying a shortwave Tuesday night/Wednesday, the better forcing looks to remain to the north of our CWA. Also, ensemble probabilities of at least 0.01" are only around 20%, so chances for accumulations are low. Thus, kept forecast dry for now; will see partly cloudy skies Tuesday night through Wednesday. The mid level ridging along with the advance of a 850 mb thermal ridge with temps approaching 17-19C by midweek means above normal temps will return to Upper MI. Chances for high temps mid to late next week pushing into the 80s are increasingly likely with lows in the 50s. Although confidence in timing is still low due to model spread, our next best chances for measurable precip likely holds off until late next weekend as a low well to the north drags a cold front through our area. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 720 PM EDT Fri Sep 6 2024 Lingering MVFR conditions will persist at KSAW overnight with predominately northerly, upslope flow. Lake effect rain/drizzle should be expected off and on at least until into the morning hours, when dry air should help end shower activity. At KCMX and KIWD, scattered lake induced cloud cover is expected to persist tonight. Conditions should primarily be VFR, but some tempo MVFR ceilings can`t be ruled out. && .MARINE... Issued at 339 PM EDT Fri Sep 6 2024 North winds continue into Saturday morning as Lake Superior sits between high pressure descending into the Upper Mississippi River Valley and a deepening low pressure system moving north into Quebec. Gusts up to 20-25 kts are expected over the west half of the lake with gusts up to 30 kts over the east half through early tonight. Late tonight through Saturday, gusts over the west hold 20 kts or less with gusts up to 20-25 kts over the east. As the high pressure flattens out over the Mid Mississippi River and Ohio River Valleys, winds back west Saturday into Saturday night, gradually diminishing to around 20 kts or less Saturday night. West winds increase late Saturday night/Sunday morning to 20-25 kts, strongest over the west half of the lake. Winds fall back below 20 kts Sunday evening. South winds return late in the day Monday, remaining less than 20 kts across the lake through the rest of the forecast period. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Beach Hazards Statement until 9 PM EDT this evening for MIZ005- 006. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...LC LONG TERM...Jablonski AVIATION...JTP MARINE...Jablonski
Area Forecast Discussion
National Weather Service Phoenix AZ
450 PM MST Fri Sep 6 2024 .UPDATE...Updated 00z Aviation Discussion. && .SYNOPSIS... Unseasonably strong high pressure over the region will continue to support excessively hot temperatures with highs exceeding 110 degrees for most lower desert locations this afternoon. Some modest relief from the heat is expected starting this weekend as temperatures retreat to around 4 to 6 degrees above normal. Breezy easterly winds during the morning hours are expected each day through this weekend across much of the area. A slight moisture increase for today and Saturday should also bring some very isolated showers and maybe a few storms over higher terrain areas before conditions dry out again heading into next week. && .DISCUSSION... Today started off on a warm note, especially in South-Central AZ where breezy easterly gradient winds this morning inhibited radiational surface cooling. Phoenix set a new record warm low for both the day and the month of September with 93F. Much of South-Central AZ lower deserts only fell into the upper-80s to lower-90s this morning. Despite the warm start, midday temperatures 3-6 degrees cooler than yesterday`s midday readings, and this applies to most of the region. So, it is not expected to get quite as hot this afternoon as it did yesterday. Still, forecast highs are around 107-114F across the lower deserts, leading to widespread Major HeatRisk. Heading into this weekend, high pressure is expected to remain situated over the region, but weaken slightly, with models showing H5 heights falling from the 594-595dm they are at now to 589-591dm by the end of the day Saturday. This weakening of the high will allow for afternoon temperatures to moderate/cool another 2-4 degrees this weekend, dropping most lower desert locations into the Moderate HeatRisk category. There will still be isolated areas of Major HeatRisk, based on the latest forecast, out in the western lower deserts. As a result the Excessive Heat Warning has been extended through this weekend for areas along the Colorado River, including the City of Yuma. Otherwise, the warning will expire elsewhere this evening. There was a push of low level moisture into the region overnight, with mesoanalysis showing PWATs around 1.0-1.2". This moisture increase will support showers and storms the next few days. This afternoon, HREF has the best chances mainly along the White Mtns and Rim. The HRRR has been consistently supporting isolated convection in Southern Maricopa County, in the Tabletop Mesa area, but it is an outlier compared to the other HREF members. The HRRR continues to be somewhat of an outlier for Saturday as well, particularly with the intensity and coverage of convection. On Saturday, and Sunday, shower and storm chances do at least expand to the western deserts. Afternoon convective development the next few days will favor typical high terrain areas and features and likely will struggle to survive once descending off the high terrain. Areas most favorable or convection across Southern AZ and SoCal this weekend will be the Kofas area up through La Paz County and the higher terrain of Riverside County CA, including Joshua Tree NP. Any shower or storm the next few days will be capable of producing strong winds (>35 mph). With high cloud bases and the T-Td spreads, DCAPE will be quite high (1700-2100 J/kg). Overall, rainfall will likely remain limited given the dry sub-cloud layer and limited instability, but any storms anchoring to a terrain feature, like in western Joshua Tree NP, could lead to minor flood impacts. Heading into next week drier air is expected to continue to shift into the region, ending any rain chances across southeast California and southern Arizona. The high pressure ridge will also begin to weaken again early next week with H5 heights lowering by mid week as a large trough gradually shifts southeastward across the Western U.S. Forecast temperatures still hover roughly 5 degrees above normal through Tuesday, but the trough should eventually drop highs to below 105 degrees by around next Thursday. The trough is also expected to turn flow out of the southwest from around Wednesday through at least late next week and this will keep dry air in place with surface dew points mostly in the 30s to lower 40s. Long range guidance still tries to show an increase in moisture by around next weekend, but the likely lingering influence of the trough may be enough to keep any deeper moisture from reaching the Desert Southwest. && .AVIATION...Updated at 2350Z. South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No major aviation concerns are expected during the TAF period under FEW mid level clouds mainly aoa 11 kft. Winds will predominantly be out of the E/SE through the period, though some light speeds, periods of variability, and potentially a brief west switch (aob 5 kt sustained) will be possible through around 04Z this evening. Isolated convective activity developed across high terrain areas to the north and east of the Phoenix metro this afternoon, and further isolated development over parts of SW AZ cannot be ruled out as we head into the early evening, but chances for TAF sites are too low to warrant any mention of VCSH/VCTS. The main impact of any of this distant convection for the remainder of today will be the potential for outflow winds to reach the terminals, most likely from the NE/E, later in the evening. E/SE winds will prevail after 04-05Z this evening and are expected to gust to around 20 kts Saturday morning. Tomorrow afternoon and evening, distant mountain thunderstorm activity is once again anticipated over the high terrain of South-Central AZ and parts of SW AZ. Hi-Res guidance is in fair agreement that the main impact of any thunderstorm activity tomorrow will once again be gusty outflow winds, most likely out of the NE, reaching the terminals as early as 00-01Z in the late afternoon. Southeast California/Southwest Arizona including KIPL and KBLH: No aviation concerns are expected through at least midday tomorrow under FEW mid level clouds. Winds at KIPL will be prevail out of the SE through the TAF period, with speeds mainly aob 10 kt sustained. At KBLH, diurnal trends will prevail, with periods of variability Saturday morning. Isolated thunderstorms are expected to develop over prominent terrain features of SW AZ and SE CA tomorrow afternoon. Though the chances of storms directly impacting either of the terminals are too low to mention in the TAF (5% or less at KIPL and less than 15% at KBLH), abrupt wind shifts from any thunderstorm outflows will become a concern at both terminals. && .FIRE WEATHER... Hot, overall dry conditions, and breezy easterly winds are expected through Sunday. A slight increase in moisture today into Saturday may bring some isolated higher terrain showers and maybe a thunderstorm or two, but chances are fairly low and CWR are less than 10%. Breezy easterly winds are expected to develop again Saturday and Sunday morning across much of the area with gusts in the eastern districts along ridgetops up to around 30 mph. These easterly winds will diminish during the afternoons. Humidities will improve for today and Saturday with afternoon MinRHs around 15% across the lower elevations to 25-30% over far eastern districts. Conditions will then dry out again into next week as temperatures remain at least a few degrees above normal each day. && .CLIMATE... Record highs: Date Phoenix Yuma El Centro ---- ------- ---- --------- Sep 6 113 in 2020 115 in 2020 118 in 2020 && .PSR WATCHES/WARNINGS/ADVISORIES... AZ... Excessive Heat Warning until 8 PM MST this evening for AZZ531- 533>544-546-548>551-553>555-559. Excessive Heat Warning from 8 PM this evening to 8 PM MST Sunday for AZZ530-532. CA... Excessive Heat Warning until 8 PM PDT this evening for CAZ560>568-570. Excessive Heat Warning from 8 PM this evening to 8 PM PDT Sunday for CAZ569. && $$ DISCUSSION...Benedict/Kuhlman AVIATION...Whittock FIRE WEATHER...Kuhlman CLIMATE...18
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
845 PM EDT Fri Sep 6 2024 ...New UPDATE, AVIATION... .UPDATE... Issued at 845 PM EDT Fri Sep 6 2024 Convection has moved into the interior as the west coast sea breeze has drifted inland this evening, but the east coast sea breeze has been moving quickly west and has overwhelmed the west coast sea breeze. Scattered convection has developed along and behind the east coast sea breeze and will continue through the late evening hours. Majority of these showers and thunderstorms should stay over the interior, but could see a few move back closer to the coast around Tampa Bay and the Nature Coast over the next few hours. For Saturday a more south to southwest flow will setup so we could see some late morning and early afternoon convection near the coast, but the majority of the showers and thunderstorms will be over the interior during the mid to late afternoon and evening hours. The exception will likely be southwest Florida where the flow will start out more southeasterly then become southwest later in the afternoon allowing convection to develop closer to the coast. Overall the current forecast looks good with no changes needed. && .AVIATION... (00Z TAFS) Issued at 845 PM EDT Fri Sep 6 2024 Scattered convection will continue around LAL this evening, otherwise rain-free VFR conditions are expected into early morning Saturday. Some areas of MVFR ceilings will be possible with daytime heating during the mid to late morning hours with scattered convection developing in the early afternoon near the coast then moving into the interior by evening causing some MVFR/local IFR conditions. Light winds overnight will become south at 5 to 10 knots during Saturday morning then shifting to southwest to west during the afternoon. && .DISCUSSION... Issued at 207 PM EDT Fri Sep 6 2024 The synoptic pattern shows weak upper ridging and surface high pressure sitting over the mid-Atlantic states. A surface low continues to spin off the New England coastline in the northern Atlantic. The associated frontal boundary extends southwest through the western Atlantic, becoming stationary over northern Florida and extending further westward through the northern Gulf of Mexico to another surface low over the western Gulf of Mexico. Upper ridging and surface high pressure continues to ridge west across central and southwest Florida. Not a whole lot of change in this pattern is expected through the period. Overall, high pressure remains north over the mid-Atlantic states and over south Florida with the stationary boundary remaining situated over northern and central Florida through the forecast period. The biggest change will be a slight shift in winds from a southwest through southeast flow to a more easterly flow by the start of next week. With all that said, we will remain predominately on the south side of that stationary frontal boundary keeping west central and southwest Florida in a warm and moist environment. PWAT values will remain quite high ranging between 2.0 - 2.4 inches over the region. This will continue to support scattered to numerous showers and storms each day. The latest HRRR guidance for today has showers and storms developing early afternoon along the west coast and SW Florida and traversing inland during the late afternoon/evening on a SE through SW wind flow. The highest rain chances will be over the interior counties east of I-75. As we have seen over the past few days, some of these storms could cause some localized flooding impacts over already saturated soils. All of west central and southwest Florida remains in a Marginal Risk of Excessive Rainfall for today with parts of central and northern Florida remaining in a Marginal Risk of Excessive Rainfall through the weekend. Daytime highs will top out in the upper 80`s to low 90`s, with heat indices reaching 100-105 degrees each day. && .MARINE... Issued at 207 PM EDT Fri Sep 6 2024 Southeast through southwest winds around 10 knots and seas 2 feet or less expected through the weekend, with a weak sea breeze possible near the coast each afternoon. Winds become more easterly by the beginning of next week and slightly increasing to around 10-15 knots. Daily showers and storms will be possible each day through the weekend and into next week. No headlines are expected. && .FIRE WEATHER... Issued at 207 PM EDT Fri Sep 6 2024 A stationary frontal boundary remains stretched across northern Florida with high pressure over south Florida. This pattern will favor warm and humid weather through the weekend and into next week. Scattered to numerous showers and storms can be expected each day through the period. No fire weather concerns are expected. && .PRELIMINARY POINT TEMPS/POPS... TPA 77 91 76 91 / 30 50 20 70 FMY 77 93 77 93 / 30 60 40 60 GIF 75 94 75 92 / 50 60 30 70 SRQ 77 91 76 92 / 20 30 30 60 BKV 73 92 73 91 / 30 50 20 70 SPG 80 91 80 91 / 20 40 30 60 && Sea Breeze Thunderstorm Regime For Saturday: 4 Sea Breeze Thunderstorm Regime For Sunday: 6 For additional information on sea breeze regimes, go to: https://www.weather.gov/tbw/ThunderstormClimatology && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ UPDATE/AVIATION...Close DISCUSSION/MARINE/FIRE WEATHER...Wynn DECISION SUPPORT/UPPER AIR/CLIMATE...Hurt/Ulevicius