Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/07/22

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
612 PM CDT Thu Oct 6 2022 ...New AVIATION... .SHORT TERM... (Tonight through Friday night) Issued at 133 PM CDT Thu Oct 6 2022 Latest GOES-16 Water Vapor imagery shows southwesterly flow aloft and mid to high level clouds streaming into South-Central Texas. A weak shortwave feature, as forecast by the latest CAMS and 18Z RAP will swing through the forecast area this evening through Friday morning, with perhaps enough lift to trigger an isolated shower or two along the Rio Grande. However, with exceedingly dry surface air and little to no CAPE to work with, believe that any showers that do attempt to form east of the Rio Grande Plains will more than likely produce virga and no measurable precipitation at the surface. That being said, bumped PoPs up to less than 10% for most locations west of I-35, but have kept mention of showers out of the forecast for now. If anything does make it to the surface, it won`t provide any sort of lasting relief to our ongoing drought conditions. More more high clouds and broken skies overnight, expect less radiational cooling to take place, with temperatures generally in in the lower to middle 60s as compared to the widespread 50s we`ve seen most mornings for the past week or so. Temperatures both this afternoon and Friday afternoon will climb into the 80s west of US-281 and upper 80s to lower 90s east of US-281. && .LONG TERM... (Saturday through Thursday) Issued at 133 PM CDT Thu Oct 6 2022 For the most part, quiet weather is expected to continue through the long term. At the beginning of the period, a cutoff low is expected to be centered over Baja California, with longwave troughing aloft across the northeastern CONUS. Through the weekend the longwave trough will push east into the Atlantic and the cutoff low will gradually diminish. This leaves fairly weak west to southwesterly flow over south central Texas. The only potential weather maker through the weekend would be a wave of vorticity that ejects northeast from the cutoff low. This piece of energy could spark some isolated to widely scattered shower and thunderstorm activity across the Rio Grande Plains Sunday afternoon into Monday, but the low to mid levels of the atmosphere will be fairly dry so some or much of this activity may be virga. Heading into the middle of next week, another longwave trough is expected to move from British Columbia into the Upper Midwest. This system could push a weak cold front into our region by the end of the period which would be our next best chance for precipitation, though unfortunately nothing widespread or significant is expected at this time in terms of precipitation coverage or QPF. A surface high will move into the southeastern CONUS from the northern Plains by this weekend. This will bring a weak, reinforcing shot of drier air to help maintain cool morning temperatures through the weekend. However, once the high moves off further to the east, we will see winds become southeasterly which will help advect greater surface moisture into the region from the Gulf until the next front arrives towards the end of the period. Consequently, mornings will become increasingly muggy by the middle of next week. Highs will remain more steady in the 80s to lower 90s, though the increasing humidity may make it feel less comfortable. && .AVIATION... (00Z TAFS) Issued at 605 PM CDT Thu Oct 6 2022 VFR conditions are expected across area terminals. Mid to high clouds are forecast to arrive from the southwest as an upper level flow dominates the region. Surface winds are forecast to be from the east and southeast through the period. Light and variable this evening through Friday morning and around 5 to 10 knots in the afternoon. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 64 91 66 92 / 0 0 0 0 Austin Bergstrom Intl Airport 63 92 62 90 / 0 0 0 0 New Braunfels Muni Airport 65 92 65 93 / 0 10 0 0 Burnet Muni Airport 63 90 63 88 / 0 0 0 0 Del Rio Intl Airport 64 86 66 85 / 10 10 10 10 Georgetown Muni Airport 63 91 62 89 / 0 0 0 0 Hondo Muni Airport 64 89 63 90 / 10 10 10 0 San Marcos Muni Airport 63 91 63 92 / 0 0 0 0 La Grange - Fayette Regional 63 93 64 92 / 0 0 0 0 San Antonio Intl Airport 66 90 67 90 / 10 10 0 0 Stinson Muni Airport 68 91 67 92 / 10 10 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...17 Long-Term...04 Aviation...17
Area Forecast Discussion
National Weather Service Gray ME
1025 PM EDT Thu Oct 6 2022 .SYNOPSIS... A strong cold front brings rain showers and isolated thunderstorms to the region tomorrow and tomorrow night with much cooler temperatures over the weekend behind the front. Another front passes through on Sunday afternoon, then a cool area of high pressure builds in behind the front for the early and middle part of next week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Latest 0222Z Update... Temperatures continue to lower towards the current dew points this hour. Fog will begin to develop rapidly late this evening with mainly clear skies and light winds. Shower activity remains well to the west over northern and central New York State per latest radar imagery. This precipitation may reach northern portions of our forecast area late tonight into tomorrow morning. Update... Update this evening for the near term portion of the forecast. Clouds remain primarily located over western Vermont and New York state per latest satellite imagery. This will spring east during the overnight hours. Latest HREF scenario suggests low clouds may attempt to enter the coastline later tonight as well. A few showers may enter far northern areas later tonight and early tomorrow morning associated with a prefrontal trough. Patchy fog expected to form as well ahead of the advancing clouds. Prev Disc... Shortwave ridging through this evening is short-lived in the progressive northern stream, which sends a trough through the Great Lakes region tonight and across New England tomorrow. For us locally, this means increasing clouds overnight along with a warm and humid southwesterly flow... at least aloft. At the surface, light flow goes calm in many areas, allowing decoupling to occur with lows in upper-40s to low-50s and fog development. Up into the mountains, height falls mark the approach of the trough from the west, with increasing chances for rain showers by dawn. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... A trough of low pressure swings from a positive to a negative tilt as it pushes out of the northern Great Lakes region and into Quebec on Friday, sending a cold front through New England. While the stratiform baroclinic leaf portion of the storm will be north of the region, closer to its parent forcing... a trailing cold front will bring rain showers and perhaps line of gusty convection to New Hampshire and Maine through the afternoon into the evening hours, tracking quickly from West to East. Friday morning, rain showers will be increasing over the mountains, with a few showers/sprinkles south of the mountains...forced by a prefrontal trough as the front itself crosses Lake Champlain. By about 12-2 PM the front crosses the Connecticut River Valley... pushing out over the Gulf of Maine and Downeast by about 7-9 PM. With surface/ML-based destabilization and steepening lapse rates aloft... and adequate shear... am expecting isolated to scattered thunderstorms to form along or ahead of the front. The front itself is likely to bring some gusty winds, with the HRRR showing 25-30 kt gusts for a brief time after FROPA. Otherwise, expect greatest coverage of showers and storms across the north although showers are still likely to reach the coast as well... just not everywhere. Cool and dry air quickly fills in behind the cold front Friday evening and overnight. Upsloping showers will continue over the mountains, but a transition to snow is expected at least across the peaks before wrapping up entirely Saturday morning. A loss of cloud ice may lead to some drizzle...or freezing drizzle... as well. Low-level CAA looks to be strong enough through the overnight to keep us relatively well mixed, with winds turning west-northwesterly and remaining somewhat gusty. This should prevent the bottom from entirely dropping out in terms of temperatures... with lows in the low-30s toward the north and closer to 40 near the coast. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Overview... A ridge axis passes through the Northeast on Saturday as the high pressure center moves across the southern tier of the country. A cold front passes through New England later on Sunday, with a cool high pressure following the front and becoming centered across New England for the early to mid part of next week. By Thursday, the high pressure center drifts offshore with a moderating return flow bringing milder conditions by the end of next week. Details... Some lingering rain and snow showers across the mountains dissipate by the afternoon hours. Seasonably cool conditions are expected on Saturday, with highs in the 40s across the north and 50s across central and southern areas. Temperatures cool into the 30s in most areas Saturday night, but with the ridge axis transiting through it doesn`t look to be an overly strong radiational cooling night. Still, with such a cool airmass in place, some sub-freezing temperatures are likely away from the coastline. On Sunday, a cold front approaches and crosses through by late in the day. This brings a brief warm up on Sunday on southwesterly flow as temps warm back into the low 60s along the coastal plain. A few showers are likely with the fronts` passage across northern areas, which likely end as a few snowflakes again across the higher terrain Sunday night. High pressure builds into the area on Monday from Canada, bringing a return to seasonably cool conditions for early next week. Conditions Monday night and Tuesday night look good for radiational cooling with the high pressure centered across New England. Started to trend a little cooler than NBM for these nights with this forecast, but held off on go too strong from this far out knowing that any cloud cover could limit the potential. By late in the week the high drifts offshore and temperatures climb back into the 60s across most of the area for at least a couple of days. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... Short Term...VFR prevails for the remainder of today with light southerly flow going variable or calm overnight. LIFR fog development may develop at some of the usual suspects tonight including KLEB/KAUG/KRKD... and at KCON with stronger decoupling. Conditions return to or remain VFR early Friday, except at KHIE where off- and-on MVFR ceilings and SHRA last for much of the day. Elsewhere, brief restrictions are possible as a cold front with SHRA crosses. Southwesterly winds 5-15 kts are expected ahead of this front, and will shift toward the west behind the front with gusts to around 20- 25 kts possible. The front itself could produce locally stronger gusts, along with a few thunderstorms. Steady west- northwesterly flow continues Friday night with VFR, except for in upslope flow at KHIE with MVFR CIGS/SHRA... perhaps SHRASN late. Long Term...VFR conditions are expected Saturday through midday Sunday, then a few showers are possible late Sunday afternoon and evening. VFR conditions return Sunday night and persist through midweek as high pressure settles across New England. && .MARINE... Short Term...High pressure slips through the Gulf of Maine tonight with light and variable flow turning southerly Friday morning. Southerly flow increases through the day, gusting to around 20 kts by the afternoon... before a cold front crosses later in the afternoon and evening. The front brings a wind westerly wind shift and rain showers with wind gusts around 25 kts, locally higher with showers and perhaps a thunderstorm accompanying the front, persisting over the outer waters into Saturday morning. Long Term...Near SCA conditions are possible Sunday in southerly flow ahead of a cold front. The front pushes through Sunday night. High pressure follows the front and brings tranquil conditions through midweek as it settles across the waters. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR/SHORT TERM...Cannon LONG TERM...Clair
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
939 PM CDT Thu Oct 6 2022 .UPDATE... Issued at 939 PM CDT Thu Oct 6 2022 After an early evening lull in surface winds, the magnitudes are re-increasing as a secondary push of lower tropospheric colder air and surface pressure gradient tightening occurs. This secondary push (i.e. cold frontal boundary) seen well on FAA TDWRs has recently advanced inland along the lake front. Wind gusts on marine platforms have gusted as high as 40 mph at Kenosha, WI and to 38 mph at the southern Lake Michigan open water buoy. So would expect similar along the immediate lakefront from ~10 PM through early overnight, with a gradual tapering through lake adjacent counties. This secondary push of colder air is also resulting in a further destabilized marine layer. Disorganized lake effect showers should gradually become more sustained through daybreak as convergence increases in the midst of lake-induced CAPE values of 150-400 J/kg. Equilibrium levels are forecast to peak Friday morning into early afternoon, but it will be a race against drier column air moving in. All-in-all, convection allowing models (CAMs) do support a peak in lake effect rain shower footprint and intensity during the morning. Some of these models even provide isolated QPF values over one half inch in/near downtown Chicago. It`s always difficult to predict the positioning of these "bands" (whether rain or snow!) more than a few hours in advance unless the convergence in the low-level wind field is already well- defined, which it is not yet. So tough to get real precise, but portions of central/southern Cook County, eastern Will County, and Lake County, Indiana are most favored to have some showers during the morning commute. Otherwise, little changes made to temperatures which should start Friday around 40F in north central Illinois to near 50F in downtown Chicago. MTF && .SHORT TERM... Issued at 255 PM CDT Thu Oct 6 2022 Through Friday... A cold front is trekking southward through the northern CWA this afternoon. A broken line of showers follows closely behind bringing light rain to a good portion of Lake County, IL with a few very spotty showers popping up further west. This line has not produced any lightning since mid-morning when it was still pushing through central Wisconsin aside from one lone cell pushing through McHenry County. RAP guidance still shows a few hundred joules of CAPE near the line through about 4:00 with low level lapse rates on the order of 8 K/km or greater with plenty of moisture through the unstable layer. The biggest contributor to the lack of convection appears to be a lack of ascent. Lift along the boundary appears a bit too gradual, for the most part, to produce thunderstorms given the limited instability and the absence of any notable forcing aloft, especially now that the broad deformation zone seems to have worn away. Both the RAP and HRRR suggest that as many as 900 joules of CAPE could build in the western CWA between 3:00 and 4:00 which would likely promoted a couple of pulse thunderstorms and, as of 2:20, a few returns are beginning to pop up on radar out in Lee and DeKalb Counties. With the instability and lapse rates both expected to readily weaken heading into the latter part of the afternoon, thunderstorm activity should be limited to areas near and north of I- 80. Not much has managed to form behind this line and with mid-level instability being very marginal, the potential for post-frontal activity should be very limited. This line will depart the CWA to the southeast this evening. A large High approaching from the north following the frontal passage will cause winds to accelerate through the afternoon eventually featuring regular gusts to near 30 mph. Winds will gradually die down through the overnight and Friday morning as the surface pressure gradient loosens up with the front departing to the south. Tonight, a potential for some lake-effect showers arrives along with a chance for a few waterspouts. Overnight into early Friday morning, sfc-850mb delta-T`s will be approaching 20C over the lake resulting in several hundred joules of lake-induced CAPE and steep lapse rates through the lowest ~200mb. A stable layer at around 700mb will keep lake-induced EL`s capped at around 10,000 ft. Guidance is suggesting an area of strong convergence setting up along the Cook and Lake (IN) County lakeshore which looks to be reinforced in the early morning hours of Friday as NNE winds onshore back to NNW. Efficient rainfall could result with several convective- allowing models throwing up a couple tenths of an inch of QPF. These lake-effect showers should push primarily over NW Indiana by mid- morning and fizzle away entirely by the late morning/early afternoon. The rest of Friday will be dry with more sun out west than over the metro and highs only reaching the lower and middle 50`s. Doom && .LONG TERM... Issued at 255 PM CDT Thu Oct 6 2022 Friday night through Wednesday... Strong cold air advection under a surface high expected to be positioned across the mid Mississippi River Valley will be in full effect at the start of the long term period. This will lead to chilly temperatures to start our Saturday with lows expected to be in the low to mid-30s across most of northeastern Illinois and northwest Indiana. Couple these chilly temperatures with the mostly clear skies and fairly light winds and widespread frost does look likely Friday night into Saturday morning with isolated pockets of freeze conditions. Guidance has continued to trend slightly warmer with the overnight lows on Friday night which is leading to some uncertainty in whether or not freeze conditions would be realized. Regardless, measures should be taken to protect sensitive plants Friday night due to the frost potential. The surface high is expected to remain in control of our weather through much of the weekend which will keep skies mostly sunny, but temperatures will be on the cool side especially on Saturday as highs will struggle to reach 60 degrees. Winds will also be breezy on Saturday with gusts currently forecast to be around 20 mph with higher gusts possible over the lake. The breezy winds are expected to linger into Sunday as well, but should gradually begin to ease Sunday afternoon and evening as the surface high departs the area. Temperatures on Sunday will also be more mild with highs expected to warm into the mid to upper 60s. Guidance continues to show a weak cold front moving through Sunday, but the expected lack of moisture in the lower levels should keep most areas dry with the small possibility of a brief sprinkle overnight Sunday night though I have maintained a dry forecast for now. A gradually warming trend in temperatures is expected through the end of the period with highs looking to be near 70 by the middle of next week. However, a stronger cold front is expected to move through the area sometime on Wednesday which will bring better chances for showers. Guidance is showing uncertainty in the exact timing of the frontal passage, but most guidance is hinting at the later portions of the day on Wednesday. There is also a small chance that an isolated rumble of thunder could also be possible given the decent lapse rates aloft Wednesday afternoon, but given the potential late arrival of the front the window of best instability looks to be somewhat limited. For this reason I have maintained a mention of just showers for now given the time range and uncertainty. Yack && .AVIATION... For the 00Z TAFs... The concerns with the Chicago area TAFs tonight and Friday are: * A temporary lull in winds early this evening that will likely cause some direction fluctuation between NNW and NNE * Gustier winds returning late this evening and persisting through midday Friday, with again some fluctuations between NNW and NNE * Lake effect showers and temporary MVFR conditions likely for MDW and possible for ORD late tonight and Friday morning The primary cold front has passed and some of the initial showers behind it should largely clear the TAF sites by 01Z. There is a temporary lull (2-3 hours) in the gustier winds that will envelop the Chicago area through 02Z to 03Z. Confidence in specifics of winds is lower than usual for a good portion of this TAF, and that`s especially true this evening. The wind direction already has and likely will continue to show some fluctuation in direction. Through 03Z, when the wind direction is from 340-350 degrees, it will likely will be 9 kt or less. After that time, including even into Friday morning, fluctuations of more gustier winds is probable. Both ORD and MDW look likely that they will see 350-010 directions during their morning push, and at this time confidence is equal for NNW vs. NNE. So this will continue to be evaluated through tonight and refined as needed in TAF AMDs. As cooler air moves in aloft, instability will develop over the warmer waters of the lake by late this evening and persist into Friday. Enough moisture will be present for lake effect MVFR clouds likely at MDW and GYY, as well as focused convergence for rain showers. The signal in high-resolution guidance is for this to be mainly an MDW and GYY concern, with the channel of showers favored to remain to the east of ORD. Unfortunately the mesoscale nature of such shower bands yield lower confidence on specifics beyond a few hours. There is a signal that where this corridor of showers is most persistent, temporary IFR visibility may occur. By afternoon, the lake effect showers should be weakening as they shift eastward over the southern part of the lake. Confidence increases that the wind direction will turn more NNW in that time. MTF && .MARINE... Issued at 939 PM CDT Thu Oct 6 2022 Have hoisted a Gale Warning into the overnight hours due to a potent surge of north-northeast winds behind a second cold front. Gusts upstream of 35 kt at Kenosha, WI and a 9 PM CDT ship observation of 38 kt about 35-40 miles north of the Indiana shoreline confirm that gales are being observed shortly behind this front, and the environment supports these lasting for at least a few hours. Waves accordingly are building sharply, and would expect some double digit heights at the least occasionally in both the Illinois and Indiana nearshores overnight and early Friday morning. Winds will ease through mid to late Friday morning into the afternoon, with waves slow to subside through Friday night. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...Gale Warning...nearshore waters until 4 AM Friday. Small Craft Advisory...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744- LMZ745...4 AM Friday to 10 PM Friday. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at: