Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/20/20

Area Forecast Discussion
National Weather Service La Crosse WI
445 PM CST Thu Nov 19 2020 .SHORT TERM...(This evening through Friday) Issued at 227 PM CST Thu Nov 19 2020 A weak cold front was positioned along the Interstate 35 corridor at 20Z with a slight decrease in temperature behind it. Further northwest, a secondary cold front was seen across northern MN extending to near the ND/SD border. Satellite indicated a sharp low-cloud boundary just behind that front and stronger cold advection push /per 925mb RAP analysis/. Overnight the colder air will filter in as both fronts pass through. By morning, the model consensus on the Dakotas low-cloud deck is around about I-94 to I-90. Overall, Friday will be cooler as 925mb temperatures drop about 10C from today...with northwest winds gusting to 20 mph. .LONG TERM...(Friday night through Thursday) Issued at 227 PM CST Thu Nov 19 2020 The cold front will bring a colder air mass into the region as a longwave trough develops over the upper Midwest. Overall minor weather expected now for the weekend, with precipitation chances holding off until Sunday. There is fairly good agreement on a moderate-strong 300-500mb Q-vector Convergence signal moving through Sunday in the latest 19.12Z GEM/NAM/GFS/ECMWF. Mid-level lapse rates are >7C/km - not too shabby. The low-level QG forcing is rather meh however, and mainly focused north of the area. Isentropic lift is very weak or nil in the low-levels as well. Thus, it looks cloudy, and the deterministic models show a light QPF signal. The 19.06Z GEFS means of 0.01-0.05" across the area Sunday also confirm this signal. Around 50% of the 19.00Z ECMWF ensemble family members show some light precipitation falling. Thus, for now, have continued small precipitation chances for rain/snow most areas and snow north of I-94. This may be a low QPF, high precipitation chance event as it draws closer. No travel impacts across WI are seen for the deer hunting weekend. Monday through Thanksgiving... A progressive pattern continues into this period and the wave amplitude does increase across the CONUS. A stronger system still looks like it will affect the area Monday night into Tuesday night with precipitation. The 19.00Z ECMWF EPS ensemble suggests an increase in both the mean amount and precipitating members for this system, over the 18.12Z run. The mean is around 0.30" in southern WI and northeast IA with amounts decreasing further north. The 19.06Z EPS agrees well with the 00Z run. Temperature profiles could result in accumulating snow before a change over to rain. The GEFS 19.06Z is more aggressive, further north, and more convective with the precipitation amounts with 0.75-1" means across much of the area. Again, similar signals of mainly a rain system, with some snow possible at onset. The GFS/GEFS seem too aggressive with the initial wave and precipitation totals compared to the family of solutions. This system will bear watching, especially it is comes in Monday night with colder air still in place - or the track shifts a bit south - as accumulating snow would be possible. Thanksgiving looks like a quiet day regionwide at this time. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 445 PM CST Thu Nov 19 2020 Relatively low forecast confidence for this forecast cycle with ceilings the primary challenge. This evening expect VFR conditions with SCT-BKN mid/high clouds and light winds becoming northwesterly behind a cold front. An area of IFR/MVFR stratus across northern MN at this time is expected to progress south and east behind a secondary surge of cooler air tonight. There is potential for these clouds to reach as far south as KRST/KLSE towards sunrise Friday with IFR/MVFR conditions for at least a period during the morning. Given the uncertainty in southward extent, opted not to include any MVFR ceilings at this point, but this will be monitored for subsequent updates. NW winds will gust to around 20 kts at times Friday && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Baumgardt LONG TERM...Baumgardt AVIATION...JM
Area Forecast Discussion...Updated
National Weather Service Billings MT
836 PM MST Thu Nov 19 2020 .UPDATE... Updated the forecast to bring wind speeds closer to observed trends. Winds were still gusty over parts of the area at 03Z as very steep lapse rates and virga allowed winds to mix down. As airmass stabilizes overnight, expect gusts to wane in frequency. A weak back door front was moving into the eastern zones given pressure rises over NE MT and a wind shift to the N. Despite echoes on radar, have seen no evidence of precipitation reaching the ground, except for some recent light snow in KBZN. Left the low PoPs alone to cover any precipitation that does reach the ground especially as temp/dewpoint spreads lessen with time. Dry forecast later tonight looked fine as airmass stabilizes. Some stratus was observed over NE MT and some HRRR runs hinted at light fog over E MT tonight. Since this has not occurred in the NE, will not add fog to the forecast. Arthur && .DISCUSSION... Tonight through Friday night... Winds will increase from Harlowton to Big Timber to Livingston with gusts up to 45 mph. Winds will also increase on the plains with gusts to 35 mph, decreasing after sunset. Shower activity will remain over counties along the ND border through early evening before diminishing. Any rain that does fall will remain light. Snow showers will occur over the mountains but amounts will remain light with the highest peaks seeing 1-2 additional inches overnight. Friday will remain drier with wind from Harlowton to Big Timber to Livingston. Winds will gust to 40 mph but those winds are expected early and will diminish during the afternoon. Low temperatures tonight will drop into the 20s, warming into the 40s for Friday. Friday night will be slightly cooler with temperatures west of Big Timber dropping into the teens and areas east dropping into the 20s. Carrothers Saturday through Thursday... Mainly dry conditions will persist through the extended forecast period, with the exception of mountain snow. Expect to see mainly seasonal temperatures throughout the extended period. Upper level ridging will build into the region following a fairly quick moving, weak cold front crossing the region Saturday. Expect no precip with this system, but a brief period of gusty NW winds, with gusts around 25 mph, are expected. The ridging will prevail through Sunday, and shift east Monday morning. Monday and Tuesday will see increasing SW Pacific flow, bringing rain/snow chances for the western mountains. There is some potential for isolated showers into lower elevations southwest of Billings Monday night, as the trough crosses the region. That said, best potential for appreciable precip will be over higher terrain, as most of the energy is progged to shift south of the CWA. Shortwave ridging progged to build in for Tuesday evening/night, before yet another shortwave moves through the region on Wednesday. This shortwave will bringing more mountain snow, but little chance into the lower elevations through Thursday. The bigger concern through the extended period is wind potential, as the Pacific flow strengthens early next week. The pattern suggests a few days of gusty winds in the foothills for the middle of next week, but uncertainty remains. We will continue to to watch model trends in the coming days for a better read on winds. Gilstad && .AVIATION... An unstable upper level disturbance continues to bring isolated showers this evening to eastern routes and high terrain, with local MVFR. Mountains will be frequently obscured in snow showers. West winds continue to gust 30-40 knots along the western foothills, and 20-30 knots further east. Shower activity is expected to end by late evening, and VFR will prevail tonight. Gilstad && .PRELIMINARY POINT TEMP/POPS... Fri Sat Sun Mon Tue Wed Thu ----------------------------------------------------------- BIL 028/046 026/046 024/045 027/046 027/046 031/046 026/042 10/U 00/U 00/U 00/E 10/N 11/B 11/B LVM 024/041 019/041 018/044 023/042 022/043 026/040 021/038 20/N 00/U 00/U 01/N 10/N 23/W 21/N HDN 026/048 021/047 021/049 021/047 023/048 026/048 024/044 10/U 00/U 00/U 00/E 10/U 11/B 21/B MLS 026/045 023/045 022/045 021/043 023/045 026/047 024/041 20/U 00/B 00/U 00/E 00/U 00/B 00/B 4BQ 028/045 023/046 023/046 022/046 024/046 026/048 025/042 20/U 00/U 00/U 00/B 00/U 00/B 11/B BHK 023/042 023/044 020/043 020/042 021/042 026/046 022/039 10/U 00/U 00/U 00/B 00/U 00/N 00/B SHR 021/043 016/045 017/046 019/047 019/046 023/048 021/040 10/U 00/U 00/U 00/B 10/U 11/B 21/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$
Area Forecast Discussion
National Weather Service Glasgow MT
150 PM MST Thu Nov 19 2020 .DISCUSSION... A backdoor cold front and snowpack made it hard for many locations along and north of Highway 2 today to mix out. Low clouds also helped to keep these locations close to the freezing mark while areas to the south reached the 40s to near 50. Canadian surface high will nose into the area tonight providing a cooler night especially where skies are clear with light winds and some snowcover. RAP and CMC suggesting temperatures fall to near zero in north-central Phillips and Valley counties by Friday morning. The surface high will drift into the northern Plains Friday with a weak front bringing in clouds early Saturday. Mainly dry and seasonably cool conditions will continue into the Thanksgiving holiday. Cold front early Wednesday looks to bring just wind and cooler airmass from the Prairie provinces into Thanksgiving. TFJ && .AVIATION... IFR clouds/visibility will linger across the area tonight as a shallow cold airmass settles in. WINDS: Look for light NW winds tonight to become Light and Variable Friday morning. TFJ && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$
Area Forecast Discussion
National Weather Service Hanford CA
430 PM PST Thu Nov 19 2020 ...UPDATED AIR QUALITY SECTION... .SYNOPSIS... Cool, near seasonal highs are expected to occur for the next seven days. A disturbance will pass through the area on Monday, which could provide the Sierra Nevada with a slight chance of precipitation. Otherwise, expect the rest of Central California to remain dry for the next seven days. && .DISCUSSION... Some patchy fog formed earlier this morning in the valley portion of Kern County, and mixed out by late morning. In the northern portion of the San Joaquin Valley, a stream of high clouds is currently passing through and will continue to do so for the rest of the day, eventually getting the central and south valley tonight. In terms of fog tonight, the latest HRRR isn`t showing much fog -- perhaps the incoming upper cloud cover will help avoid a fog event. Anyways, expect near normal temperatures today, meaning highs in the mid 60s. Afternoon highs are expected to drop in the low 60s as a couple of embedded disturbances pass through the region this weekend. Highs in the low 60s are a couple degrees below average. Morning lows by Saturday will be on the cool side, likely in the low to mid 30s. By late Sunday/early Monday, an upper level low will approach the forecast area. This low is likely to be moisture-starved, but could trigger a shower or two over the Sierra Nevada by Monday afternoon. Weak upper ridging is forecast by Tuesday and Wednesday, but it won`t be enough to move the temperature forecast much. Expect low 60s for afternoon highs to continue next week, including Thanksgiving Day. Dry weather is likely to continue for most of the forecast area in the foreseeable future. && .AVIATION... MVFR visibility due to mist is possible in San Joaquin Valley from 08z Friday to 16z Friday. Otherwise, VFR conditions will prevail for the next 24 ours across the Central California Interior. && .AIR QUALITY ISSUES... On Friday November 20 2020...Fireplace/Wood Stove Burning Status is: No Burning Unless Registered in Fresno and Kern Counties. Further information is available at && .CERTAINTY... The level of certainty for days 1 and 2 is high. The level of certainty for days 3 through 7 is medium. Certainty levels include low...medium...and high. Please visit for additional information an/or to provide feedback. && .HNX WATCHES/WARNINGS/ADVISORIES... None. && $$ public...Bollenbacher aviation....Bollenbacher
National Weather Service Wilmington OH
940 PM EST Thu Nov 19 2020 .SYNOPSIS... A weak cold front will cross through the region from northwest to southeast Friday night, with some light rain showers and sprinkles expected ahead of it beginning as early as late Friday. The front will have crossed south of the Ohio River by early Saturday. High pressure in the Upper Midwest will track east through the Great Lakes Saturday, changing winds over the region from north to northeast. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Between high pressure over eastern North Carolina and low pressure over James Bay, the Great Lakes and northern Ohio Valley remain impacted by a tight pressure gradient, with a weaker gradient in the middle Ohio Valley and closer to the Appalachians. As with last night, this is creating a scenario where winds in the northwest ILN CWA (near and north/west of Dayton) are remaining somewhat stiff -- with 30-35 MPH gusts still occurring at times. Winds in the southeast ILN CWA, on the other hand, are very weak. The going wind forecast is in fairly good shape to capture this, but this scenario will have an impact on temperatures tonight as well. The temperature gradient was sharpened in this forecast update, reflecting a slight increase in the NW, and a slight decrease in the SE. One other interesting feature tonight is the robust swath of altocumulus clouds that developed over Indiana and NW Ohio, and is now drifting east across the northern sections of the ILN forecast area. Wilmington is too far south to perfectly sample the environment in which these clouds have formed, but the 00Z KILN sounding captured some very steep lapse rates (albeit with fairly dry air) in the 700mb-500mb layer. HRRR model soundings for Lima OH (KAOH) suggest similar steep lapse rates, but also with more sufficient moisture for clouds. 700mb model plots (NAM/GFS) suggest theta-e advection as well. While these clouds are also showing up as cellular-looking echoes on KILN/KIWX/KCLE radar, the extremely dry air in the lowest 10kft means it will be very unlikely for anything to reach the ground. Previous discussion > Gusty winds will become more of a strong sustained 10-20 mph overnight as the low level jet moves away from the region to the northeast, but the axis of the weakening jet pushes into the CWA. Temperatures will stay up overnight with this wind, only dropping to near 50 in the northwest and mid 40s in the east and south. High cloud cover will thicken and lower as moisture gets squeezed ahead of the approaching front tonight. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... In continued southwest flow ahead of the front, moisture and subsequent cloud cover will increase through the day. Any chances of rain outside of a passing late day sprinkle should hold off through the daytime period as the mid levels remain fairly dry. Highs will range from 60-65. The threat for shower activity will increase in the evening and overnight, with models showing a more southerly track to the rain footprint than earlier forecast. Have shifted best chances to the south and feel that scattered light rain showers and passing sprinkles should have pops limited to just a chance. This may need to be bumped up later but the only driving force is the increased moisture in deep southwest flow being undercut by the surface cold front. Very little shortwave energy is noted. The surface front and exiting low level jet seem to be the driving force for this part of the forecast. Better chances for rain reside along the Ohio River, with little if any precip expected along and near the I-70 corridor in the northern half of CWA. None of the models are suggesting any more than a tenth of an inch at best, continuing into the extended forecast. && .LONG TERM /SATURDAY THROUGH THURSDAY/... H5 flow will be quasi-zonal to begin the period, with a Canadian cyclone swinging a cold front through the fa Saturday morning. Nearly overcast conditions are to be expected throughout the day as the front is will stall out just south of the Ohio River. The frontal boundary could produce some scattered light rain, but lack of deep layer moisture and weak isentropic lift will inhibit any long-lived or widespread development of rain. Kept only 20-30% PoPs in the grids for Saturday, but any pcpn appears to be more likely during the morning hours and further south near the stalled front. Beginning Saturday night, a warm front will begin to lift into the Ohio Valley region with a low pressure system tracking northward through the Midwest. A surge of higher RH values with the southerly flow, combined with the east-west oriented frontal boundary will lead to more widespread rain showers late Saturday night through Sunday across a broader area. Thus, have continued the trend of likely PoPs in the grids throughout the day on Sunday. GEFS and ECMWF plumes generally keep QPF values below 0.75" for this event, which seems reasonable with PWATs only in the 0.5"-1.0" range. The low pressure will quickly eject to the northeast Sunday night, leaving a decreasing trend in PoPs from west to east as we progress through the overnight hours. Removed any lingering precip chances in the blend after 12z Monday as the system will be fairly progressive. Could see a few snow flurries on the tail end of the system exiting late Sunday night, but no measurable snow expected. Surface high pressure under an H5 ridge will begin to propogate across the Midwest region. This should keep temperatures near seasonal on Monday. A relatively progressive pattern appears to be in store for next week with the meandering jet stream flow. By Tuesday, a s/w trough will begin to move into the region and provide increasing clouds, cooler temperatures and a trend towards high PoPs as we head into Tuesday night and Wednesday. This trough and associated surface low pressure will shift towards the northeast by Thursday, allowing for another high pressure system to develop and dry us out again. Temperatures appear to be on track for near or just below seasonal values for both Wednesday and Thursday. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... SSW winds will continue to diminish this evening, with gusts becoming less common after 02Z, though a few gusts to near 20kts may still occur at KDAY overnight. LLWS will also remain in place for all TAF sites. Tomorrow, winds will increase slightly, with gusts to around 20 knots possible at all TAF sites from around 14Z-21Z. Clouds will also begin to thicken, with MVFR ceilings moving in after 20Z. Precipitation appears likely to hold off until after 00Z, but some rain may impact the Cincinnati TAF sites just after that time. OUTLOOK...Occasional MVFR ceilings are possible through Sunday night. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Franks NEAR TERM...Hatzos SHORT TERM...Franks LONG TERM...Clark AVIATION...Hatzos
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
722 PM EST Thu Nov 19 2020 .DISCUSSION... Latest RAP model has mid/upper ridging across the south-central and southeastern states and the Gulf of Mexico through most of Fri. Weak troughiness in the Atlantic will drift in toward the Bahamas during Fri. At the surface an axis of high pressure resides from the Atlantic to the Deep South and spills down across the Gulf and FL...with a gradient of about 7 millibars from the GA line to the Florida Keys this evening. The high pressure begins to ease Fri and allows the gradient to relax some. The air mass continues stable and generally dry...although forecast PWAT vales of less than 1 inch this evening will increase slightly 1 inch and just above. This will be enough to support a few more clouds compared to today. In addition this moisture along with the mid/upper troughiness near the Bahamas could support scattered showers...but mainly confined to the FL east coast. Temperatures will run above normal by 2 to 3 degrees. Forecasts look good with no updates planned. && .AVIATION... 20/00Z TAF cycle. VFR. FEW to BKN SC. NE winds 08-11KT overnight then ENE 10-13KT with gusts to 20KT AFT 16Z && .MARINE... AS noted in the discussion above the gradient remains tight over night with small craft advisory conditions for most of the marine zones. Winds begin to slacken early Fri but are expected to be near or at exercise caution levels throughout the weekend. && .Preliminary Point Temps/PoPs... TPA 64 82 66 82 / 0 0 0 0 FMY 64 82 65 82 / 0 0 0 10 GIF 63 81 65 81 / 0 0 0 10 SRQ 64 82 67 82 / 0 0 0 0 BKV 59 80 62 81 / 0 0 0 0 SPG 67 79 68 80 / 0 0 0 0 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...Small Craft Advisory until 4 AM EST Friday for Coastal waters from Bonita Beach to Englewood FL out 20 NM-Coastal waters from Englewood to Tarpon Springs FL out 20 NM-Waters from Bonita Beach to Englewood FL out 20 to 60 NM-Waters from Englewood to Tarpon Springs FL out 20 to 60 NM-Waters from Tarpon Springs to Suwannee River FL out 20 to 60 NM. && $$ DISCUSSION/AVIATION/MARINE...09/Rude UPPER AIR...04/Sobien DECISION SUPPORT...04/Sobien