Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/05/21

Area Forecast Discussion
National Weather Service Grand Forks ND
954 PM CDT Thu Nov 4 2021 .UPDATE... Issued at 952 PM CDT Thu Nov 4 2021 Looking at SREF and latest NBM and also current satellite and observations all would support increased chances for low cloud/some fog to develop/spread north into WC MN, with some risk even into the RRV. Low clouds in eastern SD moving NNW and likely will be over the Couteau tonight and may try to advance into parts of SE ND but uncertain of this. Also patches of low clouds and 3-5SM fog Alexandria area moving north. So may expand fog mention a bit in MN but otherwise keep a close eye on things. UPDATE Issued at 649 PM CDT Thu Nov 4 2021 Question overnight is will low clouds and fog spread north into west central MN. Some short term model blends indicate a risk of fog and lower clouds into Fergus Falls/Wadena/Park Rapids overnight into Fri AM so did insert some fog mention this area. Fog and low clouds earlier this AM were focused just south of the fcst area around Alex to Little Falls and St Cloud and south. NBM focuses this area as well and doesnt bring it much north vs some short term blends. HRRR shows low vsbys late tonight/Fri AM in that west central MN area but pockets of lower vsbys and lower ceilings farther north/west into the RRV which when looking at the boundary layer mixing seems overdone as south winds in the boundary layer will be around 15 kts in the RRV. But fog/low clouds are advecting in and not developing so that may not play a role. Did add patchy fog to west central MN in area mentioned above to match up with DLH/MPX. && .SHORT TERM...(This evening through Friday night) Issued at 235 PM CDT Thu Nov 4 2021 Minimal impacts are expected in the short term. Ridging moves to our east to allow a low pressure system and accompanying cold front to push into the FA. The only challenges with this forecast are low chances of precipitation heading into Friday. Cirrus will continue to push into the Valley and eastward, increasing in coverage heading into tomorrow. Tonight, expect winds to remain around 8 to 15 MPH and out of the south. A transient band of clouds will pass through the FA, followed by more clouds that will stick around into Friday. Lows tonight will be in the 30s across eastern North Dakota and west central Minnesota. Friday will feature slight chance of rain showers in the afternoon alongside the frontal boundary. Winds will shift to the west and increase to 15 to 20 MPH with gusts up to 25 MPH possible. Not expecting appreciable QPF out of this system due to lack of moisture, with totals around or below 0.1". Highs across the area will reach the 50s, with the Devils Lake Basin coming close to 60 degrees. No temperature change will be immediately felt with the front, with lows returning to the mid 30s Friday evening. Clouds should leave us with mostly clear skies to start Saturday, although there are hints in the guidance of another system following closely behind. .LONG TERM...(Saturday through Thursday) Issued at 235 PM CDT Thu Nov 4 2021 Minimal sensible weather impacts expected through the long range periods, with some potential for measurable snow by the middle to later part of next week (probabilities have diminished in impactful snow amounts). Large scale pattern remains progressive with shortwave ridging followed by zonal flow this weekend into early next week. Guidance shows a decreasing trend in heights and tendency toward troughing by midweek and this signal is still there in mean ensemble heights/cluster analysis. However, the details of this trough have trended towards weaker or more progressive solutions as as such probabilities from NBM have lowered significantly on amounts. There is still a 20-40% probably of 1" or greater amounts, but the probabilities for higher than 2" are tied to outliers in the GEFS and Canadian ensemble systems. We can still say with confidence that falling heights/troughing will bring a pattern shift back towards seasonably cooler temperatures returning mid week after above average/mild temperatures this weekend (some still near 60F possible Sat/Sun). There is also a chance for dusting to 1" (20-40%) with the trough passage next week, but probabilities are becoming lower in greater impacts based on current trends. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 649 PM CDT Thu Nov 4 2021 Main question will be possibility of low clouds (IFR/lower end MVFR) and 1-3SM vsbys in fog spreading into west central MN tonight into Fri AM. Low cloud and fog development likely to our south in SW MN into central MN and boundary layer winds are southerly and most models indicate that risk of IFR conditions is high enough to mention into WC MN....but for the time being not affecting any TAF site. BJI could be close 10z-15z period. Otherwise left the rest of the area and TAF locations VFR with south winds into Friday 10 to 20 kts. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. $$ UPDATE...Riddle SHORT TERM...AK LONG TERM...DJR AVIATION...Riddle
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1045 PM CDT Thu Nov 4 2021 .UPDATE... Issued at 807 PM CDT Thu Nov 4 2021 Given HREF probs for vis less than 1/2sm and HRRR vis forecasts, did beef up fog mention in central MN for tonight. The HRRR has been slowly backing down on its fog mention though, so we may end up more with low stratus as south winds continue to strengthen through the night. && .SHORT TERM...(This evening through Friday night) Issued at 310 PM CDT Thu Nov 4 2021 Pesky fog has lingered even into the afternoon in our northern CWA but satellite trends continue to show the erosion of the bank with the last of it hopefully gone before 3pm. The main consequence of the fog taking all day to burn off has been high temperatures from St. Cloud to Alexandria and the surrounding areas, with upper 30s still within the cloud bank unlikely to rise any further than the lower 40s this afternoon. Mostly sunny skies will continue for the rest of the day as temperatures in the upper 40s to low 50s this afternoon drop back to the mid to upper 30s overnight. Another mostly clear night is expected, with fog not expected to be as prevalent due to warmer temperatures, however some patchy fog from Mille Lacs to Douglas counties remains possible. The main concern for Friday will be increasing southerly winds at 10- 15mph with some occasional gusts to 25-30mph as the pressure gradient increasing behind the departing high pressure with a weak trough bringing enough of a low pressure surface response. Forecast NAM/RAP soundings show a good enough mixed layer to support at least 30mph gusts, possibly reaching as high as 35mph along I-90. This won`t end up being close to advisory criteria, however it is something to note for high profile vehicles and anyone enjoying outdoor activities on an other warm and sunny Friday. High temperatures will reach the mid 50s to low 60s across the area due to the southerly winds and continue WAA, and despite winds weakening we could be looking at a few more 60 degree days over the weekend. .LONG TERM...(Saturday through Thursday) Issued at 310 PM CDT Thu Nov 4 2021 A warm weekend is on tap before temperatures slowly decline through the week with precip chances increasing by late in the period. After the passage of a weak trough early Saturday morning, ridging takes hold and builds through the weekend. 850mb temps will be some 10-15 C warmer than normal, giving way to a spectacular November weekend with highs well above normal in the low to mid 60s. NBM temperatures are near the 75th percentile already, and may end up needing to be bumped up a degree or two. The ridge axis will be overhead on Sunday, but increasing cloud cover associated with a warm front will likely keep highs similar to Saturday. A weak cold front will sweep through late Monday, with temperatures dropping back into the 50s. There are some discrepancies between models by early Tuesday with the passage of a shortwave across northern Minnesota and another system to our south. There doesn`t appear to be much in the way of moisture for the trough to work with, so the uncertainty with the evolution of the southern system is where a smattering of low PoPs comes from at this time. A better chance for measurable precip comes Wednesday through the end of the period. PoPs have been increased Wednesday afternoon through Thursday as a potential cut off low moves into the Northern Plains. Uncertainty is high when it comes to timing and precip type, but confidence continues to increase in the likelihood of a system impacting the region late next week. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 1045 PM CDT Thu Nov 4 2021 Biggest trend seen since 00z TAFs is a backing away from the fog, especially with the HRRR. We`re currently seeing fairly widespread MVFR vis out in central/western MN, but with winds remaining up overnight, the hi-res models have trended hard to stratus developing late tonight as opposed to fog. Pretty good model agreement on stratus impacting RWF/AXN/STC, with trends at MKT/MSP heading toward VFR conditions remaining. For winds Friday, continued trend of previous TAFs with boosting speeds over the LAV, with forecast soundings off the RAP/GFS, showing a gust potential to 40 kts as MSP and MKT. We`ll have a passing shortwave Friday evening, but it will do nothing more than bring an increase to mid/high clouds. KMSP...There`s still a small chance of IFR cigs between 12z and 15z, but those chances are diminishing. /OUTLOOK FOR KMSP/ Sat...VFR. Wind SW/W 5-10 kts. Sun...VFR. Wind SW 5-10 kts. Mon...VFR. Wind NW 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ UPDATE...MPG SHORT TERM...TDH LONG TERM...Dye AVIATION...MPG
Area Forecast Discussion
National Weather Service Marquette MI
623 PM EDT Thu Nov 4 2021 .SHORT TERM...(This evening through Friday) Issued at 311 PM EDT THU NOV 4 2021 Water vapor imagery and RAP analysis shows mid-level trough which brought cold temps and LES earlier in the week now lifting se across the Central Great Lakes this afternoon. Behind the trough, mid-level ridging will be building into the area from the west later this afternoon and tonight. This will yield dry conditions and a warming trend in the short term. A tightening of the pres gradient ahead of sfc trough approaching from the Northern Plains will also result in gusty s-sw winds across the area Fri into early Sat. These stronger winds could cause some minor lakeshore flooding along Lake Mi in southeast portions of the cwa Fri afternoon into Sat. Tonight, a sfc low pres trough will emerge over the Northern Plains. With some tightening of the pres gradient ahead of this feature, breezy conditions could develop. However, HRRR soundings suggest there will be sufficient decoupling to result in winds remaining light most areas. The exception will be in the areas that see downsloping under sw winds. In those areas, expect some gustiness to the winds tonight, up to around 20mph or so. There is some stratocu, bases at around 3kft, over northern WI off to the sw over IA. Some of these clouds may find their way to Upper MI tonight. Overall, should be a clear to partly cloudy night. Expect low temps ranging from the mid/upper 20s F s central and e to the mid 30s in the downslope areas where winds will be stronger. Friday, expect breezy conditions as the gradient continues to tighten between trough over the Northern Plains and sprawling high pressure from the mid-Mississippi Valley into New England. Under partly cloudy skies and a WAA southwest flow, look for high temps to reach near 50F. The duration of stronger south/southwesterly winds across the area and Great Lakes (as reflected in the NAEFS and ENS ensemble data) will likely cause at least minor lakeshore flooding concerns for Delta and Southern Schoolcraft Counties. Waves in Green Bay are fcst to get up to 6-7 feet, and waves along the Lake MI shoreline could get above 10 feet Friday night so have decided to post Lakeshore Flood Advisories for these areas. .LONG TERM...(Friday night through Thursday) Issued at 255 PM EDT THU NOV 4 2021 Increasing pressure gradient at the start of the long-term period will cause breezy S-SW winds into Saturday. Increasingly negatively tilting trough axis entering into the western Upper Great Lakes region at the start of this weekend will carry with it a vort max along its base, triggering low-end PoP chances across portions of the U.P. Despite this UL lifting mechanism, albeit not stout, atmospheric moisture availability with this disturbance appears to be a limiting factor for coverage and QPF. The ongoing WAA regime under said S-SW flow will allow for rain to be the dominant, and most likely only, precip type for tomorrow night into Saturday, although can`t rule out a few flakes mixing in across portions of the interior west where cooler temps/wet- bulbing could allow for that to happen. Upon this trough axis exiting the region late Saturday, zonal flow briefly takes hold overhead, on the periphery of a building ridge centered along the GoMex coastline. The upper bounds of the ridge axis traverses through the Great Lakes late this weekend into the start of the next work week, keeping Upper Michigan dry through this time period. The next precip chances arrives Tuesday into mid-week as a couple of UL troughs move through successively. Normal temperatures for this time of year generally run in the lower 40s for highs and around the 30 degree mark for lows. At the start of this forecast period, temps will be well above those norms, with highs over the weekend into early next week well into the 50s, with perhaps even a few 60s emerging on Sunday and Monday under the aforementioned stream of ample WAA. Lows will range in the 30s and 40s (warmest along the lakeshores) during this same time period, with trends looking to moderate back closer to normal by the end of the long-term period (although still generally running slightly above normal for early November). && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 623 PM EDT THU NOV 4 2021 VFR conditions will prevail at all sites thru this fcst period. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 311 PM EDT THU NOV 4 2021 W to SW winds across Lake Superior will increase today with gusts reaching 20-25kt, highest west and north central. Winds will continue to gust up to 25kt tonight into Fri morning before increasing further Fri aftn into Fri night, especially across the e half of Lake Superior. Across the e half, S to SW gales to around 35kt will likely occur Fri night so have issued a Gale Watch for LSZ266-267 23Z Fri-11Z Sat. Winds will diminish w to e on Sat with gusts blo 20kt by Sat evening. These lighter winds will continue into Sun. A trough will then sweep across Lake Superior early Mon. Some increase in winds may occur prior to, but more likely after the trough passage. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Lakeshore Flood Advisory from 2 PM Friday to 2 PM EDT Saturday for MIZ013. Lakeshore Flood Advisory from 4 PM Friday to 4 PM EDT Saturday for MIZ014. Lake Superior... Gale Watch from Friday evening through Saturday morning for LSZ266-267. Lake Michigan... Gale Watch from Friday afternoon through Saturday morning for LMZ221-248-250. && $$ SHORT TERM...Voss LONG TERM...lg AVIATION...07 MARINE...Voss
National Weather Service Morristown TN
941 PM EDT Thu Nov 4 2021 .UPDATE... EVENING UPDATE. && .DISCUSSION... Clouds continue to erode from the northwest this evening, leaving good radiational cooling conditions. With dewpoints in the upper 30s to mid 40s in many Valley locations, we should easily reach saturation in the next few hours. Latest models are showing a good amount of fog throughout the TN Valley tonight, which jives with current obs. The update will hit the mention of fog harder, and a SPS will be issued to mention dense fog in some spots. DGS && .AVIATION... 00Z TAF DISCUSSION. Clouds are retreating across East TN, and will continue to do so through the evening. This will allow for good radiational cooling conditions, and fog development overnight at all sites. The TAFs will have MVFR vis developing early, around 06Z, dropping to IFR in the 08-09Z time frame. Vis and cigs could drop to LIFR at times, which will be included in TEMPOs. With the low sun angle, fog will be slow to lift/dissipate, so will only bring VFR conditions back around noon. DGS && .PREV DISCUSSION... /ISSUED 306 PM EDT Thu Nov 4 2021/ SHORT TERM...(Tonight and Friday) Key Messages: 1. Clearing skies and cold tonight with patchy frost in much of the region and freezing temps across the Plateau, mountains, NE TN, and SW VA. 2. Sunny on Fri, but temps still 7 to 10 degrees below normal. Discussion: Late Afternoon/Evening... The mid/upper shortwave continues to move away as of mid afternoon with the associated inverted surface trough following suit, however, deep longwave troughing remains centered over the eastern CONUS feeding cold, Canadian air into the TN Valley and S Appalachians. This NW upslope flow combined with a 1028 mb surface high building S from the western OH Valley is trapping moisture below the increasingly dry and subsident mid-levels. This lingering low-level moisture (mainly below 800 mb according to RAP soundings) is keeping stratus clouds over the S Appalachians along with some sprinkles or drizzle over NE TN and the mountains. Believe the dry air will eventually make it to the surface as the aforementioned surface high continues to build in, but these patterns usually take longer to clear out than guidance suggests, so blended in the cloudier CONSSHORT guidance through the first half of the overnight. This all points to a cloudy and damp evening with temps falling through the 40`s. Tonight and Friday... The surface high will further strengthen above 1030 mb tonight while building into the lower OH Valley and central Appalachians. Even the cloudier CONSSHORT has most areas clear by 06Z except for far SE TN and SW NC, and this is supported by RAP forecast soundings which suggest the dry air reaching the surface overnight. This will allow the far SE areas to even clear out the second half of the night. The clearing skies, calm winds, and antecedent cool airmass will allow temps to fall into the upper 20`s/low 30`s from the N Plateau through NE TN and SW VA and mountains with low/mid 30`s elsewhere. Kept a Freeze Warning going for the Plateau, mountains, NE TN, and SW VA with a Frost Advisory everywhere else. Since clouds will be slower to clear over far SE TN and SW NC, started the Frost Advisory later down there (08Z), but this area is the lowest confidence. Besides the temps, patchy fog and freezing fog is a concern since soundings show small dew point depressions below the nocturnal inversion, and rivers and lakes are still relatively warm. The best chance for this river and lake fog is from the central Valley through SE TN and SW NC. The surface high overhead will lead to a pleasant, sunny day Fri, but continuation of eastern CONUS mid/upper troughing will keep highs in the mid/upper 50`s which is 7 to 10 degrees below average. Garuckas LONG TERM...(Friday Night through Thursday) Key Messages: 1. Dry weather and warming trend through mid-week next week. 2. Areas/Patchy frost and patchy early morning fog near area waterways can be expected through early next week. 3. Next significant storm system anticipated late next week but confidence on timing and strength area low. Discussion: For Friday night through Sunday, upper trough across the far southeast United States will lift northeast just off the coast of the Carolinas/Virginia with little to no impacts across the southern Appalachians. Surface ridging will continue to dominate the weather with dry conditions and cooler than normal temperatures. For Monday and Tuesday, upper ridging will build into the southern Appalachians with moderating temperatures and continued dry conditions. Surface ridging will also remain. For Wednesday and Thursday, a series of short-waves will move across the nation with the deterministic models (GFS/ECMWF/Canadian) showing different evolutions of these waves. The GEFS and ECMWF Ensemble shows the greatest chance of rain moving back into the Tennessee valley/southern Appalachians by late Wednesday through Thursday. Will have the highest PoPs during this time-frame. As typical for this late in the extended, timing and strength of these waves are low. DH && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 36 56 38 60 39 / 0 0 0 0 0 Knoxville McGhee Tyson Airport, TN 33 57 34 59 36 / 0 0 0 0 0 Oak Ridge, TN 34 56 35 59 37 / 0 0 0 0 0 Tri Cities Airport, TN 31 56 29 58 30 / 0 0 0 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...Frost Advisory from 4 AM to 10 AM EDT Friday for Cherokee-Clay. TN...Freeze Warning until 10 AM EDT /9 AM CDT/ Friday for Bledsoe- Blount Smoky Mountains-Campbell-Claiborne-Cocke Smoky Mountains-Grainger-Hamblen-Hancock-Hawkins-Johnson-Morgan- Northwest Carter-Northwest Greene-Scott-Sequatchie-Sevier Smoky Mountains-Southeast Carter-Southeast Greene-Southeast Monroe-Sullivan-Unicoi-Union-Washington. Frost Advisory from 2 AM to 10 AM EDT Friday for Anderson- Jefferson-Knox-Loudon-McMinn-Meigs-North Sevier-Northwest Blount-Northwest Cocke-Northwest Monroe-Rhea-Roane. Frost Advisory from 4 AM EDT /3 AM CDT/ to 10 AM EDT /9 AM CDT/ Friday for Bradley-East Polk-Hamilton-Marion-West Polk. VA...Freeze Warning until 10 AM EDT Friday for Lee-Russell-Scott- Washington-Wise. && $$
...Updated Aviation Forecast Discussion...

.DISCUSSION... Issued at 309 PM CDT Thu Nov 4 2021 Forecast Summary: Our warming trend through the weekend is still on track, when temperatures climb to 10 degrees above normal. More unsettled weather returns next week, with a general cooldown early in the week, followed by more dramatic cooling to end the week. Precipitation chances will accompany the unsettled weather, especially as we head toward Wednesday and Thursday. Tonight through Sunday: Areas of dense fog again graced the morning hours for northeast into south central Nebraska. With a lowering sun angle and relatively light winds, fog hung on through noon or so. Now, south winds have increased a bit during the afternoon, and most of the fog and lower clouds have scoured out. Temperatures responded to the afternoon sun nicely, rising into the 50s most areas. Southerly winds will remain overnight, maintaining or adding to low level moisture. Thus we could see more low clouds and patchy fog into Friday morning, though chances for dense fog seem much lower given stronger winds. Same conditions hold for Friday night into Saturday morning with low level moisture plume streaming through eastern Nebraska and western Iowa as per forecast soundings and RAP RH progs. A somewhat tighter diurnal temperature fluctuation may result, especially for overnight lows being a bit warmer under cloud cover. Otherwise mid level heights are trending higher through Sunday, yielding a warming low level atmosphere in response. 850 temps gain more than 10C from this afternoon through Sunday afternoon, suggesting surface temperatures easily reaching the 60s for the weekend. Monday through Thursday: Mid level heights begin to be depressed southward early next week as flow becomes southwesterly. Models are fairly consistent in showing northwest low level flow returning by Monday in the wake of a shortwave swinging through the Northern Plains. After Monday, model consensus begins to wane. We currently have a dry forecast for Tuesday, however ECMWF deterministic and several ensemble members suggest a potent shortwave producing rain over much of the region. The GFS and others are more open with the Tuesday shortwave across Nebraska, and produce rain farther to the east. The diverging solutions continue into Wednesday/Thursday when there is about an equal split of ensemble forecasts regarding a deepening upper low in the Plains or Midwest. One clustered solution deepens upper low to our east, suggesting lower precipitation chances, while the other solution deepens the low right overhead. This would bring widespread precip in the form of rain initially then snow on the back side of system as it heads east. Will need to do some fine-tuning of this part of the forecast, especially regarding precipitation chances and types. The one thing we are confident in is much cooler temperatures will plunge southward behind system, whether that be by Thursday or later. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 624 PM CDT Thu Nov 4 2021 VFR conditions are currently in place, with lowered ceilings expected to begin developing at 06z through 08z. A few pockets of lowered visibility are possible, but widespread restriction aren`t expected at this time due to the prevailing 10 kt winds. Ceilings and whatever visibility restrictions exist are expected to be replaced by VFR conditions are strong winds. Gusts could approach 30 kts or slightly higher out of the SSW before diminishing after sundown Friday. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Dergan AVIATION...Petersen
Area Forecast Discussion
National Weather Service Phoenix AZ
400 PM MST Thu Nov 4 2021 .UPDATE... Updated Aviation && .SYNOPSIS... High pressure will build over the southwest United States, resulting in mostly sunny skies and above normal temperatures across the Desert Southwest through this weekend. A cooling trend is then expected to commence early next week as high pressure shifts east of the region along with periods of slight breeziness during the middle of the week. No significant precipitation is expected during the next 7 days. && .DISCUSSION... Latest water vapor imagery and RAP streamline analysis reveal a dry northwesterly flow associated with a ridge extending northeastward from the Baja Peninsula into the northern Rockies. Temperatures are running above normal this afternoon and this trend will continue the next few days as the ridge migrates eastward and a return flow develops between an anticyclone in Mexico and low pressure across the Pacific Northwest. Latest NBM indicates Saturday will be the warmest day with roughly a 30 percent chance of high temperatures reaching the 90 degree mark in Phoenix. A high of 90 degrees also cannot be ruled out for Sunday when the probability is around 25 percent. Monday will mark a change in the pattern as heights lower in response to a short-wave trough moving eastward through California and Arizona. Latest NBM indicates high temperatures will return to near normal or possibly below normal values by Tuesday. A reinforcing trough will likely prevent lower desert high temperatures from rising much above the 80 degree mark through Friday. PoPs remain quite low early next week, as IVT ahead of the Monday system is expected to remain weak. Only one model cluster, largely comprised of CMC members, produces light QPF across the region. This equates to NBM PoPs at or below 5 percent Monday night through Wednesday morning. && .AVIATION...Updated at 2300Z South-Central Arizona including KPHX, KIWA, KSDL, and KDVT; and Southeast California/Southwest Arizona including KIPL and KBLH: Clear skies will persist Friday afternoon with no impacts to aviation interests. A light westerly drift is likely at most Phoenix terminals early this evening before reverting back to an easterly direction by mid evening. Light W/NW winds will be most prevalent at SE California sites. Conditions Friday will be nearly identical to today. && .FIRE WEATHER... Saturday through Wednesday: Above normal high temperatures are expected through Sunday with conditions remaining dry through the period. Winds will generally be light and favor diurnal patterns through Sunday with some mild afternoon breeziness developing in the western deserts during the early to mid part of next week. Min RH values in the teens through the weekend will increase to the 20s by Tue. Overnight max RHs will improve to 45-60% by early next week. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...Hirsch AVIATION...18 FIRE WEATHER...Sawtelle/Smith
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
846 PM EDT Thu Nov 4 2021 ...ISOLATED SEVERE STORMS POSSIBLE TOMORROW... .UPDATE... Radar has shown a significant uptick in activity over the last few hours, particularly well offshore. However, some showers have been working through SWFL as well, giving some folks more than an inch or so of rain based on observations. Through the night and into tomorrow, deteriorating weather conditions are expected as a low begins to organize and deepen over the central Gulf. Over the next day and a half or so, this low is expected to propagate ENE towards - and eventually over - FL before exiting out into the Atlantic. For our area, this means that there is a nonzero potential for severe weather, primarily for tomorrow (although there are already some concerning cells out there in the 60-100nm range). The biggest limiting factor is the thermodynamics. It looks fairly weak, with models suggesting CAPE values are likely to remain below 1000J/KG. Cloud cover looks to be the reason for this, and also any ongoing convection. However, there is still synoptic forcing for ascent to work with. For instance, model soundings show a strongly veering profile through 700mb. This would help to overcome the relatively weak buoyancy from daytime heating. If updrafts can grow large enough, the kinematic environment is trending in a direction that would favor at least some severe potential. The RAP is showing effective shear values of around 40kts south of I-4, and the surface- 3km layer is also showing almost 30kts for the same area. The shape of the hodographs also suggests that this is an environment that can sustain supercells, at least on an isolated basis. Right-moving supercells would have a solid amount of SRH to work with as well if they do develop in this forecasted environment (~200 m2/s2 based on the RAP). The primary hazards to look for would be gusty winds and isolated tornadoes with the strongest storms. There is also a risk of heavy rain leading to localized flooding with the shear also helping to sustain convection, and a potential for training if cells continue to propagate over the same area. As far as tonight goes, the forecast looks pretty well on track. Rain is expected to continue and increase in coverage towards morning. Some changes to winds have been made, but they are fairly minor through this evening. Despite an offshore wind flow, ocean swells are likely to propagate towards the coast as the low heads in our direction. This may elevate the rip current risk for tomorrow, but not confident enough yet to issue a statement. Overall, tomorrow looks like a pretty poor day. It looks like nicer weather won`t return until later in the weekend. && .AVIATION... Showers and isolated thunderstorms are working closer to area terminals, with SWFL sites already seeing some rain and lower CIGs in the last hour. Deteriorating conditions are expected as morning approaches, with some indications IFR CIGs may prevail for much of the day tomorrow. Haven`t completely bought into this yet, but have introduced lower, MVFR CIGs for much of the day, along with reduced VSBYs and SHRA. TEMPOs for more significant reductions may be needed as time goes along later in the forecast, and have been added to reflect some brief reductions overnight tonight. && .MARINE... Marine conditions are deteriorating with showers and thunderstorms across coastal waters. As an area of low pressure develops in the Gulf and moves towards the coast over the next day and a half, conditions continue to deteriorate with waves and seas building to Advisory levels and remaining elevated into the weekend. && .Preliminary Point Temps/PoPs... TPA 82 67 73 62 / 20 60 100 60 FMY 84 69 80 65 / 50 70 100 50 GIF 82 67 74 62 / 10 60 100 70 SRQ 82 67 76 63 / 30 60 100 60 BKV 81 61 70 57 / 10 60 100 70 SPG 81 69 74 65 / 30 60 100 60 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...Small Craft Advisory from 2 AM EDT Friday to 7 AM EST Sunday for Coastal waters from Englewood to Tarpon Springs FL out 20 NM-Coastal waters from Tarpon Springs to Suwannee River FL out 20 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. Small Craft Advisory from 2 AM EDT Saturday to 7 AM EST Sunday for Charlotte Harbor and Pine Island Sound-Coastal waters from Bonita Beach to Englewood FL out 20 NM-Tampa Bay waters-Waters from Bonita Beach to Englewood FL out 20 to 60 NM. && $$ Flannery
Area Forecast Discussion
National Weather Service Topeka KS
836 PM CDT Thu Nov 4 2021 ...AVIATION UPDATE... .DISCUSSION... Issued at 254 PM CDT Thu Nov 4 2021 Seasonably cool conditions continue this afternoon, on the upstream side of an upper trough over the eastern CONUS. To the west, an upper ridge is currently located over the Rockies, with the Plains under northwest flow aloft in between. At the surface, high pressure is located over the mid-Mississippi Valley while weak lee troughing has developed over the High Plains. Southerly winds in response to these two features have allowed for some weak low-level moisture advection, resulting in another day of stratus across portions of the area. Places underneath this stratus are still hovering around 50 degrees, while those that have received a bit more sun have warmed into the mid 50s. Overnight, some continued cloud cover and modest south winds will keep temperatures from dropping too much. Lows will generally stay around 40. Heading into tomorrow afternoon, the overall pattern will not change much. A shortwave trough will move across the northern Plains but will stay too far north to bring much in the way of impacts. At the surface, the pressure gradient will tighten up a bit, boosting afternoon south winds into the 10-20 mph range. Some cloud cover may linger into the afternoon across far eastern Kansas, but things should eventually clear out as high pressure slowly drifts farther east. With a bit of WAA advection and less cloud cover, highs should climb into the 60s across much of the area. Heading into the weekend, the ridging over the Rockies will shift eastward, allowing for the warming trend to continue. Initially through the weekend and into the start of next week, the ridge axis will stay to the west, keeping moisture return limited. As such, precipitation chances remain very low through at least Monday. By Tuesday, upper troughing will begin to amplify across the West Coast. One or two associated shortwave troughs will approach the Plains at some point mid-week. Precipitation chances will return to the area as a result, though specific timing and detail naturally remains uncertain this far out. && .AVIATION...(For the 00Z TAFS through 00Z Saturday) Issued at 836 PM CDT Thu Nov 4 2021 The MVFR CIGS have been shrinking rather than expanding early this evening. It looks like from the 00Z TOP RAOB that there is enough mixing below and above the inversion for some dry air entrainment that is causing the clouds to continue dissipating. The 00Z RAP has backed off on saturation at 925MB quite a bit. Am waiting to see what the 00Z NAM looks like, but may need to amend the forecast to back off on the CIGS with winds at 925MB progged to increase. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION...Reese AVIATION...Wolters