Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/07/21

National Weather Service Hastings NE
956 PM CDT Wed Oct 6 2021 ...Short Term Update... .UPDATE... Issued at 954 PM CDT Wed Oct 6 2021 THE BASICS: Regarding "beefing up" of fog potential for Thurs AM (especially in our eastern zones): Well, another night and another round of late night/early morning fog potential it appears. To be very honest, fog potential for tonight has ramped up a bit in various model visibility progs (particularly HRRR/RAP13) since the original afternoon discussion came out hours ago. As a result, have added generic "patchy fog" potential to the ENTIRE coverage area (CWA) from at least 5-9 AM, and have introduced "areas of fog/visibility less than 1 mile" to mainly Nebraska counties east of Hwy 281. These eastern areas actually stand a chance for at least patchy dense fog (visibility 1/4 mile or less), and although do not currently have enough confidence in the ultimate coverage of potentially-dense fog to issue a formal Dense Fog Advisory, have at least introduced the possibility to the Hazardous Weather Outlook (HWOGID), and will defer to overnight and possibly day shifts to address the possible need for an Advisory. FURTHER DETAILS: The overall synoptic setup for early AM fog development appears relatively similar to last night/early Wed AM (when at least patchy dense DID in fact develop especially some central/eastern counties). And if anything, the last several hourly runs of the HRRR/RAP are hitting potentially dense fog potential a bit harder than last night (especially for far eastern counties along/near Hwy 81). Like last night, we will have at least mostly clear skies and fairly light southeasterly breezes (especially eastern half), along with high boundary layer relative humidity (RH), which if anything may be a bit higher than last night given dewpoints currently running low-mid 50s. As a result, there is increasing confidence in at least "some" fog development mainly after 5 AM, some of which could be impactful to the morning commute, especially eastern zones. While the highest concerns (and greatest potential for a possible eventual Advisory...NOT a sure thing of course) resides within eastern counties, felt it would be prudent to blanket the ENTIRE CWA with a generic "patchy fog" mention, although SREF visibility probs suggest our far southwestern counties would be most favored to remain largely fog-free. QUICK NOTE ABOUT LOW TEMPS BEING LOWERED: Last night, we saw low temps drop generally 2-4 degrees degrees below our official forecast in many areas, and although the slightly higher dewpoints tonight should keep things a few degrees "warmer" than last night overall, still opted to drop lows a good 1-3 degrees from the initial afternoon forecast issuance. The result is more of the CWA now aimed into the low 50s (versus mid 50s), and even have some upper 40s far north (Ord area). && .DISCUSSION...(This evening through Wednesday) Issued at 243 PM CDT Wed Oct 6 2021 Main issues to consider for this forecast will be extent of cloudiness today into tomorrow, a cold front passage Saturday evening, and precip chance uncertainty for Sunday night into Monday. The closed upper low meandering from Arkansas into Missouri will continue to play havoc on our sky cover forecast for the rest of the day into tonight as it wobbles its influence with increased sky cover from the east, especially our eastern CWA. As for fog chances, I really think we will have less of a chance as low-level moisture profile looks even more shallow, the surface ridge will not be directly overhead, and the HRRR is backing off of fog chances compared to what was advertised this morning. This low will finally get caught in flow that will take it farther east by tomorrow, although we will have some clouds around, should not see as much as today, especially in our east. Dry period until the next wave gets closer and cold front approaches toward Saturday night. High temperatures will trend warmer until then. Ensembles are generally trending toward strengthening of the shortwave trough moving through from the southwest Sunday night into Monday. ECMWF is significantly stronger than the GFS is advertising and thus producing well over an inch of rain for most of the CWA with this system, while the GFS gives very little. With given trends, I would not be surprised to see an increase in POPs for Sunday night into Monday with future forecasts. With the potential of a stronger wave, I stuck in thunder for Sunday night into Monday. Kept thunder for parts of the CWA in for Tuesday. Cooler temps are still expected behind the cold front Saturday evening, with highs Sunday and beyond in the 60s to mid 70s. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Friday) Issued at 716 PM CDT Wed Oct 6 2021 General overview: The period is almost guaranteed rain-free, and confidence is high that at least the vast majority of the time will feature VFR ceiling/visibility. In fact, the TAFs officially reflect VFR throughout, although there are admittedly some question marks especially between 10-15Z as there is a non-zero chance for at least brief fog and/or low ceilings. Ceiling/visibility: High confidence that the vast majority of the period is VFR, featuring no more than very limited clouds (both low and high level possible)...and actually prevailing mostly clear most of the time. However, after seeing a round of "sneaky" fog briefly become an issue Wednesday AM, am a bit concerned that a "repeat performance" could try to occur Thursday AM as well given fairly similar conditions. Most models/guidance focus any widespread/potentially dense fog issues at least 25-50 miles east and/or north of KGRI/KEAR, but at least light MVFR fog (and perhaps a brief MVFR/IFR ceiling) would not be a big surprise. For now, have only opted to "hint" at possible reduced visbility with a low-end VFR "6SM BR" group focused 10-15Z, and will defer to later issuances to keep a close eye on visibility/ceiling trends. Winds: Things are more straightforward here. Direction will remain fairly consistent from southeasterly to south-southeasterly. Speeds overnight will average under 10KT, but by late morning-early afternoon Thursday a touch of breeziness will kick in with sustained speeds averaging around 12-13KT/gusts 15-20KT. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...Pfannkuch DISCUSSION...Heinlein AVIATION...Pfannkuch
Area Forecast Discussion
National Weather Service Goodland KS
950 PM MDT Wed Oct 6 2021 .SHORT TERM...(This evening through Thursday) Issued at 241 PM MDT Wed Oct 6 2021 RAP analysis and water vapor imagery shows a large low pressure system over the Missouri Valley region and a trough located over the Rockies. The start of the afternoon has the forecast on track as these two synoptic features begin to collide with one another which is resulting in tightening of pressure gradients over the Tri- State area. Winds have gusted slightly higher than expected at KGLD with 33 mph the strongest observed thus far. The remainder of the afternoon is expected to remain dry as the Tri-State area remains in between the two systems, showers develop along the Front Range and move east late this afternoon and into the evening, but confidence is currently low if they will be able to sustain themselves into the eastern Colorado counties. Tonight, clouds move in west to east as the trough moves by just to the west of the CWA. Guidance has been indicating that a piece of energy breaks off from the trough and moves through Yuma and Dundy counties. This along with forecast soundings showing moistening mid levels through the night which will create the chance for sprinkles and perhaps and an isolated light rain shower through sunrise. Overnight lows are forecasted to be in the mid 40s to lower 50s. Thursday, elevated fire weather concerns continue for eastern Colorado, albeit slightly tempered from previous days as RH values fall into the low to mid 20s. Breezy winds in the morning due to a surface low over SW Kansas will gradually decrease through the day with afternoon highs mainly in the low 80s; morning wind gusts of 20- 25 miles per hour are possible along and south of Interstate 70. Thursday night clouds again increase from the west as overnight lows fall into the mid 40s to lower 50s across the area. .LONG TERM...(Friday through Wednesday) Issued at 250 PM MDT Wed Oct 6 2021 Friday...the upper level pattern features the forecast area under a fast southwest flow aloft, in between an upper level trough along the west coast of the country and an upper level ridge from Texas northeast into the northern plains. High clouds are expected to move across the area from southwest to northeast with no precipitation expected. High temperatures are forecast to reach into the low to mid 80s. Overnight low temperatures are expected to be in the low to mid 50s. Saturday...Fridays west coast trough shifts east into the northern plains southwest into New Mexico as a larger upper level trough approaches the Pacific Northwest. High clouds will continue to periodically streak across the area from southwest to northeast. There is a bit of moisture in the 700-500mb layer that move into the northern portion of the area during the late afternoon and evening hours sliding east and south after midnight supporting a slight chance for some rain showers. Southwest winds pick up a bit across far eastern Colorado in the afternoon ahead of a cold front that moves through the area during the night. High temperatures reach into the mid 70s to low 80s in far eastern Colorado, low 80s to around 90 elsewhere, hottest in the Hill City area. In fact, the forecast high of 90 degrees in Hill City would tie the record high for the date set back in 1965. Low temperatures drop into the low 40s to low 50s. Sunday...a closed upper level low associated with the trough mentioned above approaches the Texas panhandle in the afternoon then toward eastern Kansas overnight. There are some timing differences between the GFS and ECMWF regarding the speed of movement with the GFS faster. The current forecast follows the slower ECMWF and supports rain showers/possibly a thunderstorm. High temperatures cool down into the mid 60s to mid 70s with low temperatures in the upper 30s to upper 40s. Monday...a significant change in the weather patter begins with the GFS/ECMWF/Canadian and GEFS models in good agreement carving out a strong/deep upper level low pressure area over Nevada and Utah by sunrise Tuesday morning. Rain chances decrease from west to east during the day with sunshine returning to much of the area. Dry conditions are currently expected during the night. The ECMWF is a little faster bringing some moisture in the 850-500mb layer and perhaps a rain shower into parts of far eastern Colorado. High temperatures remain in the mid 60s to mid 70s. Low temperatures are expected to be in the upper 30s to upper 40s. Tuesday...the 12z GFS/ECMWF/Canadian and GEFS models shunt the deep closed upper low into the four corners area during the day with a deepening surface low somewhere across eastern Colorado. The synoptic setup is favorable for blowing dust/possible dust storm conditions. Based on the GFS model and local ongoing research the parameters are favorable for an organized threat of blowing dust and unhealthy air quality to move northeast out of south central Colorado and into our area (mainly across far eastern Colorado) during the afternoon. The ECMWF wind profile isnt nearly as favorable. Stay tuned as any shift in the upper level low will shift the axis of strongest winds, either to the west of our area or east or completely fall apart. High temperatures range from the upper 60s to upper 70s. Surface winds will likely need to be increased as well given the pressure gradient. A few rain showers and thunderstorms are possible, mainly along the KS/NE border and eastern CWA while the rest of the area is dry slotted. For the overnight hours there is some timing differences regarding how the upper low lifts northeast. The GFS is faster putting the upper low into the Nebraska panhandle while the ECMWF has it near the Palmer Divide. The Canadian model has it over south central Colorado. The GEFS has it in between the GFS and ECMWF. The timing of this is critical in how cold temperatures get on the backside of the low, if at all. Currently low temperatures are expected to range from the low to upper 30s in far eastern Colorado to the upper 30s to near 50 east of the CO/KS border. Despite the current forecast of slight chance and low chance pops there is a pronounced mid level dry slot over all but the far eastern Colorado counties which should limit qpf potential quite a bit. But for now will keep the pop forecast going. So with that said we`ll be watching for the possibility of some snow mixing in with some rain around the Flagler area. Confidence is rather low in the precipitation and temperature forecast at this time. Wednesday...The dynamic storm system lifts northeast into the northern plains with precipitation chances decreasing from south to north during the day. Breezy west to northwest winds are expected. High temperatures are expected to be in the mid 50s to low 60s in far eastern Colorado, low 60s to around 70 elsewhere. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 946 PM MDT Wed Oct 6 2021 At KGLD terminal, VFR conditions are expected through the TAF period. Southeast winds are expected to gradually diminish after midnight. There is a brief period between 07 and 09Z where some low level wind shear may be possible. Winds turn light and variable around sunrise, becoming northerly by mid-morning around 09kts. Winds become light and variable in the afternoon. At KMCK, VFR conditions are expected for the forecast period. Southeast winds persist through the overnight hours. A brief period of low level wind shear will be possible between 08 and 11Z. Low confidence in the potential for some patchy fog to develop around 12Z in the vicinity of the terminal. Winds through the day will be light and variable. && .CLIMATE... Issued at 250 PM MDT Wed Oct 6 2021 A record or near record high temperature is possible at the following location Saturday, October 9: Hill City..........90 degrees set back in 1965 && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...TT LONG TERM...99 AVIATION...AW CLIMATE...99
Area Forecast Discussion
National Weather Service Wilmington NC
815 PM EDT Wed Oct 6 2021 .SYNOPSIS... Showers and storms will gradually increase this week as tropical moisture moves into the region. Above normal temperatures are expected much of this week, particularly morning lows. Unsettled weather will continue into early next week as a wave of low pressure meanders off of the Southeast coast. && .UPDATE... Minor adjustments to previous forecast based on current radar trends. High res near term guidance not handling current situation very well. HRRR having trouble with the activity near Cape Fear, but there is an area of enhanced moisture at 850/700mb showing up in the high res guidance. This moisture combined with some weak isentropic lift is likely the cause of the ongoing activity. The enhanced moisture in these layers slowly shifts west-northwest during the overnight hours and remains in the vicinity of weak speed enhancement at 850/700mb. Not significant enough to call it a low level jet, but it is likely to play a role in rain/showers continuing overnight. Temperatures well above climo with clouds and tropical moisture in place. && .NEAR TERM /THROUGH THURSDAY NIGHT/... Tropical moisture feed via onshore low level flow will maintain scattered showers across NE SC through this evening. Ample cloud cover has kept showers shallow and lightning free. A swath of precipitable water near 2" moves up the coast tonight as a tropical wave strengthens as it moves up the SE coast. Best chance of rain will be near the coast from south to north after midnight through Thursday morning. Well above normal low temps tonight near 70 with cloudy skies and scattered precip. Rain chances linger through Thursday with trough/weak low offshore and persisting low level onshore flow. Closed upper low continues to move north across the Midwest before opening into a wave Thursday night as it approaches the Great Lakes. This will turn flow aloft to westerly and dries out the mid and upper levels. Better chance for scattered thunderstorms Thursday with daytime heating. High temps around 80-82. Rain chances decrease Thursday night, but remain in the slight chance range, with lows in the upper 60s. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... Very unsettled weather this period with SW flow aloft around upper low moving into Great Lakes and surface/low level flow onshore and moisture-laden. And while the chance for rain will be ever present there is no forcing for it to ever be very heavy. The antecedent ridge will lead to one last mild afternoon, while extensive cloud cover will keep nighttime lows quite elevated. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... An uncertain forecast on Saturday. Upper trough axis to swing through arguing for a drying trend while possible tropical or hybrid low off the coast-its position uncertain and thus how far west it manages to fling moisture. More certain drying slated for Sunday as the upper wave continues east and the offshore low accelerates away from the area. Mid level ridge will build for the remainder of the period keeping the area dry and bringing a slight warming trend. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... VFR conditions will continue into the first part of Thu before ceilings start to drop. Increase in low level moisture and isentropic lift helps spread a lower cloud deck over the area. Inland areas will flirt with IFR by daybreak while along the coast 1500 to 2000 ft seems more likely. Ceilings start to lift by mid-morning and could see breaks in the the deck by early afternoon as the bulk of the moisture shifts off to the north. Winds will remain out of the northeast with speeds generally under 10 kt. Extended Outlook...MVFR conditions could develop in association with clouds and multiple rounds of showers through the end of the week. && .MARINE... Through Thursday Night...While not at advisory levels, marine conditions this evening into overnight will be a bit rough. Northeast winds 15-20 kts, occasional gusts to 25 kt, and seas 3-4 ft with 5 footers in outer coastal waters. Conditions improve before sunrise tomorrow morning with the pinched gradient relaxing as a tropical wave approaches from the south. ENE winds Thursday and Thursday night generally 10-15 kts with seas 3-4 ft. Seas will be a mix of a 7-8 sec SE swell and a 2 ft NE wind wave. Best chance for showers and thunderstorms over coastal waters will be tonight. Friday through Monday...Winds to be out of the N to NE for the entire period. High pressure passing by well to our north will be the primary wind-maker. A weak and small low well offshore will make a contribution as well, but tend to stay far enough offshore to bring any increase in speeds. Seas will tend to build as time wears on both as the NE fetch becomes more and more established and a small easterly swell component materializes. && .TIDES/COASTAL FLOODING... Combination of a new moon this morning and persistent onshore flow will contribute to coastal flooding risk through end of the week. Along the Lower Cape Fear River at Downtown Wilmington, coastal flooding is forecasted with each high tide through at least Friday. Morning high tides will be the higher of the two, with the evening high tides currently forecasted right at 5.5`. For the beaches, New Hanover and Pender county beaches are forecasted to experience minor coastal flooding Thursday and Friday mornings, with southern beaches going over Friday morning. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...High Rip Current Risk from 6 AM EDT Thursday through Thursday evening for NCZ106-108. Coastal Flood Advisory until midnight EDT tonight for NCZ107. MARINE...None. && $$ SYNOPSIS...ILM UPDATE...III NEAR TERM...VAO SHORT TERM...MBB LONG TERM...MBB AVIATION...III MARINE...ILM TIDES/COASTAL FLOODING...VAO
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
657 PM CDT Wed Oct 6 2021 .SHORT TERM...(This evening through Thursday night) Issued at 252 PM CDT Wed Oct 6 2021 The stratus deck that moved up from the southeast this morning is narrowing and where the sun has been able to come out CU fields have developed. The NBM was pretty aggressive in reducing cloud cover overnight, so in coordination with neighboring offices we bumped up the cloud coverage overnight. An upper low will move north out of the Arkansas/Missouri area, more or less tracking along the Mississippi River, and advect deeper moisture into our forecast area. This will bring the chance for isolated to scattered showers tomorrow. Reduced the PoPs a bit for tomorrow as the NBM PoPs looked overdone. Rainfall totals look to be quite light with only a few hundredths, to perhaps a tenth of an inch. The best chance for any showers will be in eastern Minnesota and west central Wisconsin. There is some CAPE in the forecast, so some thunder is possible, particularly in southern Minnesota. Clouds overnight should keep the threat of fog pretty minimal. The chance for showers will continue into Thursday evening before winding down overnight as the upper low gets caught up in the southwest flow aloft and begins tracking more to the northeast. Not much change in temperatures through the short term. Highs tomorrow will be mainly in the low to mid 70s with the warmest temperatures in western Minnesota. Lows tonight will fall into the 50s, to around 60 in the Metro area, with clouds increasing. Low temperatures tomorrow night will be similar, perhaps a degree or two .LONG TERM...(Friday through Wednesday) Issued at 252 PM CDT Wed Oct 6 2021 The already above normal temperatures are forecast to climb even more Friday into Saturday as a thermal ridge builds into the Central Plains from the southwest. Highs Friday and Saturday are forecast in the mid to upper 70s, with a chance of isolated 80s. In fact, the deterministic ECWMF and GFS show MSP reaching 80 at least one day to end the week. Lows Friday and Saturday night will be in the mid to upper 50s, with the Twin Cities heat island remaining slightly warmer. Showers are possible across our eastern CWA Friday afternoon as a weak, cutoff low over the Mississippi River Valley slowly meanders northward. This disturbance will eventually make its way into the Great Lakes before getting caught up in the upper-level flow and traveling east. Meanwhile, our next good chance of precip looks to be Saturday into Sunday as a vorticity maximum associated with a positively tilted trough over CA/NV breaks off and travels northeast into the Northern Plains. A strong, 140 knot southwesterly jetstreak ahead of the vorticity max should allow for a deepening surface low, moving from the Dakotas across northern MN into Sunday night. Guidance favors the heaviest area of precip along the northern periphery of the low near the warm front and deformation zone. To the south, the moisture profile in the low to mid-levels is drier causing models to be more stingy with rain. As such, NBM has likely to definite PoPs across northern MN, decreasing to chance then slight chance PoPs as one goes south to southern MN. QPF amounts follow the same regime with perhaps our northern MN counties nearing an inch total for the weekend. Guidance does hint multiple inches across northwest MN; an area that desperately needs rain. Heading into early next week, models amplify a vast upper-level ridge across eastern North America in response to strong low-level WAA. The placement and strength of this ridge should act to steer any future systems northward as they enter the central CONUS. Indeed, another chance of rain is possible across the Upper Midwest Monday into Monday night as the remainder of the aforementioned CA/NV trough finally ejects east of the Rockies. Following this system is when things could get really interesting. A strong upper- level jetstreak is forecast to dive south along the west coast Monday, highly amplifying a trough over the western CONUS by Monday night. Long range models show this trough crossing the Rockies and ejecting northeast into the Northern Plains by mid-next week. While timing and placement uncertainty exists, ensembles and deterministic guidance seem to agree that there will be a strong low and surface cyclone affecting some part of the north-central CONUS Wednesday into Thursday. Thus, our first strong low pressure system for the Fall season could be on the horizon. Temperatures for next week are forecast to cool but still remain slightly above normal for early to mid October (normal highs are in the lower 60s while lows are in the lower 40s.) && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 657 PM CDT Wed Oct 6 2021 The biggest issue this period surrounds around MVFR stratus timing/extent on Thursday. Trends for precip are on a downward direction for the day on Thursday, but increasing Thursday evening (after this period for all but MSP). For the stratus, favored the more conservative GFS for bringing it in and how far northwest to take it. This did delay when MN terminals see the stratus and we introduced it into WI as well. RAP/HRRR are a bit more aggressive with the stratus for both bringing it in earlier and spreading it across all MPX terminals, so continued modifications to the cig forecast are likely. KMSP...RAP shows stratus moving into MSP as early as 11z and quite a bit lower (IFR) than the GFS. However, with the sub-VFR stratus currently just a narrow east-west band of MVFR cigs from the Quad Cities to Chicago, not confident enough in the RAP to go that aggressive yet. /OUTLOOK FOR KMSP/ Fri...VFR. Wind S 5-10 kts. Sat...VFR. Chc MVFR/-SHRA. Wind SE 15G25 kts. Sun...VFR. Chc MVFR/-SHRA. Wind W 10-15 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ SHORT TERM...CEO LONG TERM...CTG AVIATION...MPG
Area Forecast Discussion
National Weather Service Nashville TN
1048 PM CDT Wed Oct 6 2021 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Allowed the Tornado Watch to expire as scheduled at 10pm, and have continued the Flash Flood Watch through 7am as previously issued. Latest radar imagery shows numerous showers and storms continue across the area, mainly the eastern half of the cwa, with numerous flash flood warnings and flood advisories ongoing. Although showers and storms will gradually diminish in coverage overnight per latest HRRR model runs, any additional rainfall could cause flooding - especially in the watch area where radar estimates show 1 to over 6 inches of rain has fallen today. Instability has diminished across the area so the threat for severe weather and brief tornadoes has decreased, but cannot rule out a strong storm or two. Have updated grids and zones based on latest radar trends and short term models. && .AVIATION... 00Z TAF DISCUSSION. Upper level impulse will work northward this evening across primarily the eastern half of the mid state. Airmass is rather unstable and strong to severe storm potential will remain for CSV through 03Z. Aft 03Z, showers to continue through at least 08Z to 10Z. Elsewhere, western and central middle TN taf sites will lean toward NSW aft 06Z. Across the east, convective coverage should begin to decrease late tonight with this trend continuing into the day on Thursday. && .OHX WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch until 7 AM CDT Thursday for Bedford-Coffee- Cumberland-Giles-Grundy-Lawrence-Marshall-Van Buren-Warren-Wayne. && $$ DISCUSSION......Shamburger AVIATION........21