Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/12/22

Area Forecast Discussion
National Weather Service Boston/Norton MA
1023 PM EDT Wed May 11 2022 .SYNOPSIS... Stratus and fog moves across southern New England tonight and again Thursday night with temperatures climbing above normal. Summerlike warmth on Thursday away from the coast with clearing skies. Considerable cloudiness Friday into the weekend but also more summerlike temperatures and seasonably elevated humidity levels. Periods of diurnal showers possible as well, but the better chance for showers or thunderstorms is with a cold frontal passage either Monday or Tuesday. More seasonable temperatures return by midweek. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 1020 PM update... Stratus starting to push west across eastern New Eng with western edge from PVD-BED. Forecast challenge for overnight is how far inland does the stratus penetrate as low level moisture advects westward with persistent low level easterly flow. Followed HRRR time lagged ensemble which is handling areal coverage of clouds pretty well and suggests low clouds will reach as far inland as roughly BDL to FIT with mainly clear skies across NW MA. A few light showers are pivoting west across the Islands. Patchy drizzle possible overnight across SE New Eng as mid levels dry out. Patchy fog confined to outer Cape/Islands and may expand across eastern MA into RI overnight but not expecting fog to particularly dense, except perhaps at ACK and outer Cape. Previous discussion... * Stratus and fog spreading over much of southern New England tonight. May have areas of dense fog across the Cape/Islands along with drizzle. Stuck in this persistent pattern of a cutoff parked southeast of the Carolinas and a highly amplified ridge building over the Great Lakes region. Will be caught between high pressure nudging in from Quebec and a vertically stacked low east of the Carolinas. The high will gradually continue to assert itself over southern New England tonight. Unfortunately due to the position of these two features we will continue to see E/ENE flow in the low/mid mid level, which will advect the marine layer into southern New England. This will result in low cloud spreading in along with patchy fog for a good portion of the region tonight. There is a risk for areas of dense fog across the Cape/Islands late tonight. May actually need to issue a Dense Fog Advisory, but confidence at this point isn`t high enough to hoist one up. Again think that the risk is highest for the Cape/Islands. On top of this there may be enough convergence from a wind directional shift coupled with the low level moisture for drizzle/light rain across the Cape/Islands. Given the cloud cover in place and easterly wind direction will not see temps drop too much tonight. Will be roughly 5 degrees warmer than normal for this time of year with readings ranging from the upper 40s to the low 50s. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... Highlights * Thursday morning stratus/fog clears out for most by late AM/early afternoon. Though it may linger for the Cape/Islands. Summer warmth anticipated for areas away from the immediate coastline. * Stratus/fog advects back in Thursday night into early Friday. Could see some light rain/drizzle across the south coast. Persistent cutoff southeast of the Carolinas will gradually rotate toward the SE US on Thursday and over the SE US Thursday night. A ridge axis remains over the Great Lakes region on Thursday into Thursday night. High pressure builds into New England on Thursday, but builds into Nova Scotia Thursday night. Any lingering stratus/fog burns off for much of southern New England on Thursday with high pressure builds over the region and mixing within the boundary layer scatters clouds out. Utilized the latest HREF guidance as a rough proxy for the clearing skies, but the stratus may linger across the Cape/Islands through the afternoon. Flow aloft on Thursday becomes more ESE/SE. This will result in 925 hPa temps of roughly 10-15 degrees Celsius across southern New England. Given the mixing we are anticipating and clearing skies should see summer like warmth for much of the region minus the immediate coastline. At this point went with the 75th percentile of guidance, which results in widespread 70 degree readings with some low 80s across the CT River Valley. Along the coast highs will top out in the 60s. May actually need to bump some of these temps up a bit further if we clear out more than currently anticipated. Will see the stratus and fog advect back into southern New England Thursday night into early Friday AM due to southerly flow. Given dew points will be in the 50s and once again we have some directional convergence in winds along and south of the south coast. This may be enough for some light rain/drizzle, but capped PoPs at slight chance. Will be mild across southern New England due to the southerly flow, moisture and cloud cover. Low temps in the low/mid 50s. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Highlights: * More summerlike with seasonably elevated humidity levels Fri thru the weekend. Chances for diurnally driven showers, possible pop-up thunder each day. Highs approaching 80 degrees this weekend. * Cold front around Mon or Tue brings better chances for showers and/or thunder. * More seasonable but still somewhat unsettled into midweek. Details: Friday through the Weekend: The pesky, slow-moving upper low over the mid-Atlantic states retrogrades into the central Appalachian region beginning Fri. This feature then gradually moves northward, deamplifying/phasing with a northern stream disturbance over the northern Plains/Gt Lakes later Sun. For much of this period, it translates to a warmer, more summerlike regime over SNE, but also one with considerable cloudiness and seasonably elevated humidity levels (dewpoints in the lower 60s). Proximity to the deamplifying upper low will favor better chances for showers across interior New England, but have kept lower chances into eastern MA and RI as well. Showers will tend to predominate more often than not. However there may be enough if still weak instability, driven mostly by weak mid-level lapse rates offsetting shallow subtropical moisture, for a pop up t-storm or two. Opted to leave as just showers for now with the better chances for showers being over the weekend. Confidence level on thunder is rated pretty low but isn`t zero, particularly if we can get any sustained breaks. Showers or pop-up t-storms would more closely follow the diurnal convective cycle, with higher PoP during the daylight hrs and less during the evening. Highs Fri should reach into the 70s, though cooler mid 60s near the coastlines. Even milder on Sat and Sun in the upper 60s/near 70 coasts and upper 70s to mid 80s inland. Mild lows in the upper 50s to mid 60s - I`ll stop short at calling each night muggy, but will turn somewhat more uncomfortable. Monday through Wednesday: Gt Lakes upper low becomes the dominant feature in this period. This will send a shortwave disturbance and cold front through SNE at some point either on Monday or Tuesday. Could be better chances for showers and thunderstorms with the frontal zone`s passage but timing differences - both in terms of which day or what time of day - make it difficult to assign thunder to the grids at this point. Better chances for thunder would exist during the daylight hrs. Upon its frontal passage, expect drier weather with shower coverage being more intermittent and spotty with cold pool of air aloft. This cold front`s passage will also break the seasonably elevated dewpoints and warmer temperatures to ones that are more typical for mid-May with highs in the mid 60s to low 70s. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. 00z TAF Update: Tonight: High confidence in trends, but moderate on exact timing of sub-VFR stratus. Initial VFR in the interior and coastal plain; MVFR to LIFR due to stratus and intervals of mist/fog near eastern MA/Cape Cod and Islands. Gradual westward expansion thru 06z to widespread MVFR-IFR, with IFR-LIFR stratus with areas of mist expected to be mainly confined to eastern MA and RI. Winds NE to NNE around 5-10 kts. Thursday...Moderate confidence. MVFR to IFR stratus during the morning scatters out to VFR by the afternoon. However, the lower ceilings are anticipated to persist across the Cape/Islands. NE winds at 5-10 kts shifting to the E/SE at 5-10 kts during the afternoon. Thursday night...Moderate confidence. MVFR to IFR stratus spreading back in across much of the region other than central/western MA where we may stay VFR. Could also have some drizzle/light rain along the south coast. Light and variable winds. KBOS TAF...High confidence in trends, but moderate in exact timing of MVFR/IFR ceilings. KBDL TAF...High confidence in trends, but moderate in exact timing of MVFR ceilings tonight. Outlook /Friday through Monday/... Friday: Mainly VFR, with local MVFR possible. Friday Night: Mainly VFR, with local IFR possible. Slight chance SHRA. Saturday: VFR. Chance SHRA. Saturday Night: Mainly VFR, with local IFR possible. Slight chance SHRA. Sunday: Mainly VFR, with local MVFR possible. Chance SHRA. Sunday Night: VFR. Chance SHRA. Monday: VFR. Breezy. Chance SHRA. && .MARINE... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Today through Thursday...High confidence. Tonight...High confidence. NE winds of 10-20 kts easing to 5-15 kts by late tonight. May have some 15-20 kt gusts across the southern waters this evening. Main concern is fog, which may be dense in spots along with drizzle. Seas of 4-7 ft gradually diminishing to 2-5 ft late. Thursday...High confidence. NE winds at 5-10 kts shifting to the ENE/E at 5-10 kts during the afternoon. Fog along with drizzle gradually lifts mid/late in the morning. Seas diminishing to 2-4 ft. Thursday night...High confidence. Winds out of the E/SE across the eastern waters at 5 kts and E for the southern waters at 5-10 kts. Fog along with drizzle overspreading much of the waters. Seas 2-4 ft. Outlook /Friday through Monday/... Friday through Friday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers. Saturday through Saturday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers. Sunday through Sunday Night: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain showers. Monday: Winds less than 25 kt. Seas up to 5 ft. Chance of rain showers. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until midnight EDT tonight for ANZ232>235- 237. Small Craft Advisory until 6 PM EDT Thursday for ANZ250-254. Small Craft Advisory until 8 AM EDT Thursday for ANZ251-255- 256. && $$ SYNOPSIS...BL/Loconto NEAR TERM...KJC/BL/Loconto SHORT TERM...BL LONG TERM...Loconto AVIATION...BL/Loconto MARINE...BL/Loconto
Area Forecast Discussion
National Weather Service Des Moines IA
627 PM CDT Wed May 11 2022 ...Updated for the 00z Aviation Discussion... .DISCUSSION.../Tonight through Wednesday/ Issued at 335 PM CDT Wed May 11 2022 Key messaging highlights: * Severe storms briefly possible northwest into this evening, and again tomorrow evening * Continue warm and humid into tomorrow * More seasonal temps from the weekend into midweek with a few lower end storm chances Our higher amplitude pattern will essentially remain in place through the rest of the work week after the passage of the parent western CONUS trough and PV anomaly, now moving toward the CA/NV border. In the mean time, our immediate concern will be convective trends associated with the Nebraska MCV. The warm front and associated convergence influenced by the synoptic pattern, MN outflow, and MCV to some degree, was now fully out of our forecast area leaving little low level focus this far south and east. This would leave the last two MCV lobes of lift to drive convective initiation (CI), with the HRRR suggesting the axis from northwest Iowa to south of Des Moines may activate soon. Confidence is not great however, with concerns regarding how much overly inflated AWOS dewpoints are impacting the HRRR, RAP, its offshoot SPC mesoanalysis. Several upper 70s to lower 80s dewpoints were observed, which are unrealistic versus better calibrated ASOS observations. A midday OAX sounding depicted much lower MLCAPEs than the SPC mesoanalysis as well, suggesting CI may be harder to come by this far removed from the MCV. Recent WoFS output also suggests the better potential near the core, which seems to be the case per recent radar trends. If cells can develop in the next several hours this far east they would likely only briefly reside in our forecast area, and hail and wind would seem to be the primary threats with higher LCLs and lackluster 0-1km shear, SRH, and storm relative winds diminishing tornadoes to lesser potential. Once this passes the remainder of the night appears to be dry but still warm and muggy. Looking into tomorrow, another warm and humid day is in the offing with highs into the lower 90s. Although potentially not quite as unstable as today, MLCAPEs should top 3000 J/kg with sufficiently low inhibition, especially considering the degree of kinematic forcing expected along and ahead of the aforementioned PV anomaly as it and frontogenetical support is nearly phased with the surface front convergence. Thus confidence in an MCS into western and central Iowa is much higher than today. Its intensity may diminish quickly in time however with deep shear lacking. Much like today, hail and wind would seem to be the better threats with steep mid level lapse rates and the relative lack of moisture suggesting cold pool development and elevated DCAPEs. Similar to this afternoon, there is some tornado potential, but the 0-1km LCLs and instability/shear parameter space isn`t too favorable. The convection should continue dissipating overnight into Friday morning, but may redevelop somewhat into peak heating Friday over the southeast half of the state. The severe weather potential Friday is less than today and tomorrow with less instability and similarly low deep shear values. From the weekend through the middle of next week, generally lower amplitude flow will then exist across Iowa outside of minor troughing through the Upper MS Valley late in the weekend. After this, our flow will be relatively zonal into the middle of next week. This will keep seasonal temperatures in place with no extremes anticipated. Regarding precipitation, there will be the potential for weak convection with the passage of the weekend system, and then lower confidence chances later next week with warm/theta-e advection aloft. There is no severe weather signal of note for this period at this time. && .AVIATION.../For the 00Z TAFS through 00Z Thursday evening/ Issued at 627 PM CDT Wed May 11 2022 Thunderstorms across northwest Iowa this evening will miss all TAF sites with VFR conditions persisting through the period. Breezy south winds will occasionally gust over 20 kts this evening, diminishing into Thursday. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION...Small AVIATION...Hagenhoff
Area Forecast Discussion
National Weather Service Pueblo CO
322 PM MDT Wed May 11 2022 .SHORT TERM...(This evening through Thursday) Issued at 322 PM MDT Wed May 11 2022 Key messages: 1) Widespread critical fire weather conditions are expected today and tomorrow across most of the CWA. With unusually low RH values tomorrow, extremely critical fire weather conditions are expected across many areas tomorrow afternoon. 2) Strong to severe thunderstorms will be possible later this evening over the southeastern plains. Damaging winds will be the most likely threat, but large hail may also occur. 3) Very strong winds possibly reaching High Wind Warning criteria may occur tomorrow around Noon for El Paso County. Very windy elsewhere with areas of blowing dust possible across the plains and San Luis Valley both today and tomorrow. 4) Smoke from wildfires in New Mexico will infiltrate most of southeastern Colorado. Visibilities may become reduced if the smoke makes it down to the surface. 5) Very warm temperatures and record high temperatures could be possible this afternoon for some locations in the plains and San Luis Valley/upper Arkansas River Valley. Detailed discussion: Currently... An approaching upper level low currently over Nevada is advancing towards the region and allowing for a tightening of the surface pressure gradient, which is producing very strong and gusty southwesterly winds across SE Colorado. Coupled with this is very dry air with low RH values, which is resulting in widespread critical fire weather conditions to be in place across most of the CWA. These conditions will end over the far eastern plains by early evening as a more humid airmass with higher dewpoint temperatures makes its way into the area. Also with this, the strong downsloping and adiabatically warming winds are heating up areas of the plains and San Luis Valley/upper Arkansas River Valley, to possibly temperatures that could either tie or break the previous daily record temperatures throughout the early evening hours. Colorado Springs has already broke the daily record of 87F set in 1961, with a temperature of 88F. Along with these strong and gusty winds could be the possibility of patchy or areas of blowing dust, especially in the San Luis Valley. The latest HRRR smoke also displays an infiltration of concentrated levels of smoke moving across most areas of the CWA, with a plume of extensive coverage moving in over the southern Sangre de Cristo Mountains and in a NE orientation over western Las Animas County and up to Kiowa County. Depending on how much of this smoke is mixed down to the surface, it may cause reduced visibilities. This Evening and Tonight... As the U/L low continues to move over into the plains, the flow ahead of the trough axis is going to shift to the SSE over the far eastern plains. A surface low will undergo cyclogenesis around the CO/WY/NE tri-point stateline and this will bring in a moisture tongue with a dryline developing west of the CO/KS border or even further westward depending on how far the moisture mixes. The lastest CAMs differ with how far west the moisture mixes and the progression of the dryline, which would determine where thunderstorms could initiate. The CINH cap looks to break right around 4 PM, which is likely right around the time storms will develop. The NAM3km keeps the dryline advancing back to the Otero/Bent County line by around 8PM, whereas the HRRR only has the extent of this back to western Baca County around the same time, and with much lower dewpoints. Given the biases of the CAMs, the NAM3km tends to typically resolve drylines better over the far eastern plains with synoptic forcing present. The WRF-ARW appears to be more in agreement with the HRRR, and the WRF-NSSL is in better agreement with the NAM3km and actually takes this dryline all the way westward to the Otero/Pueblo County line. The HRW-FV3 brings it back to a little closer to what the NAM3km shows as well and given which more model is reliable with resolving localized moisture scheme parameterization, it can be concluded that the extent of the higher dewpoints could mix all the way back to somewhere around the Bent/Otero County line. This indicates that thunderstorm development could potentially initiate as far west as La Junta, but as more likely to be further east towards Lamar. Bulk shear values between 0-6 km are relatively high between all of the CAMs, with values around 50 to 60 kts. Looking at soundings over areas of the eastern plains with more of an inverted V and very dry air in the lower levels with a high LCL, the profile appears to be more favorable for high-based storms with a dry microburst potential. Damaging winds would likely be the greatest threat if storms become severe, however if updrafts become strong enough to support a healthy BWER as MLCAPE values are approaching close to 2500 J/kg along the southeastern CO/KS border, some large hail could also be possible. The profile is not favorable due to high LCL levels and low SRH values for tornadoes to form with these super cells. Hodographs area fairly straight-lined, so cells have the ability to split. Winds will still be an issue going into the late evening hours for much of the CWA and RH recoveries are going to be very poor for most areas where there is still mixing going on. Critical fire weather conditions do not look to end for many areas until around 10 PM. Any remaining storms should continue to move off to the northeast and out of the CWA by around 10 PM as well. With conditions being so dry in the lower levels, lightning strikes could also trigger fire ignitions over the eastern plains, but the timeframe that this would occur looks to be earlier in the evening, between 4 and 8 PM. HRRR smoke also keeps a plume of smoke from the wildfires in New Mexico moving over the more southeastern portion of the CWA. Winds will weaken but remain gusty and also return to a more SSW`ly direction over the eastern plains by later in the night with drier air moving back in. Tomorrow... Southwesterly winds will continue to increase again tomorrow morning. There is some model guidance such as the HRRR suggesting that there is the potential for winds to strengthen to near High Wind Warning criteria by around Noon over northern and southern El Paso County and southern Pueblo County (due to a gap flow), and therefore this warning may need to be issued for a few hours for both of these counties. The NBM 4.1 highlights these areas the best. Very dry air is going to continue to also advect over with very low dewpoint temperatures, which some models such as the HRRR are suggesting could drop to around -25 to -30 degrees in certain areas and result in extremely critical fire weather conditions over areas of the plains, where RH values could be as low as 3 percent. With the stronger winds early in the late morning hours and throughout the early afternoon, there could also be areas of blowing dust. By later in the afternoon, as winds weaken, this should allow for some of the dust to have settled. The latest HRRR smoke model run also keeps the smoke plume coming from the wildfires in New Mexico over the southeastern portion of the CWA. As winds continue to shift more to the westerly direction by later in the day, this should allow some of the smoke in the lower levels to move out of the area. Winds will also decrease a bit but remain strong and gusty as they become more westerly. The more westerly winds behind the trough will also allow for cooler max temperatures tomorrow, closer to the seasonal average for this time of year. -Stewey .LONG TERM...(Thursday night through Wednesday) Issued at 322 PM MDT Wed May 11 2022 Key Message: 1) Critical fire weather conditions remain likely for Friday, especially along and west of the I-25 corridor. Thursday Night and Friday Winds will continue to decrease with clearing skies and some slight cooling in the wake of the departing trough on Thursday night. Ensemble guidance shows good agreement that a transition to zonal flow will set up for Friday, with temperatures of about 10 to 15 degrees above normal for this time of year. Daytime highs in the low 80s in the lower terrain and 70s in our mountains are expected for Friday afternoon. We will remain dry, especially in the mountains, where moisture recovery overnight appears dismal from Thursday night into Friday. Our mountain ranges and the San Luis Valley will see relative humidities falling back into the single digits by noon on Friday, but zonal flow will help to clear any remaining smoke out of our eastern plains. Winds will still be high enough to lead to fire weather conditions on Friday afternoon, especially along and west of the I-25 corridor. Friday night-Sunday...Westerly flow aloft continues to moderate and become more west to northwest through the weekend, as upper level ridging builds across the Rockies. The will keep dry weather in place across the region, with lesser expected winds through the weekend. However, there will likely be enough mixing through the afternoon hours to support areas of critical fire weather conditions across the region, mainly along and west of the I-25 Corridor. Temperatures through the weekend look to remain above seasonal levels, with highs mainly in the 80s across the plains and in the 60s and 70s across the higher terrain. Monday-Wednesday...Extended models do indicate more westerly flow developing across the region as minor embedded waves move through the Rockies into the middle of next week. Timing of said waves remain in doubt, however, there look to be some increases in available moisture to support some convection across the Rockies through the period, along with continued areas of critical fire weather conditions. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 322 PM MDT Wed May 11 2022 VFR conditions are expected at all three TAF sites, KCOS, KPUB and KALS, for the next 24 hours. Strong southerly winds have set in at KCOS and KPUB, and will not be weakening at all until after 03Z this evening. Expecting winds to stay fairly gusty overnight as well. Right now visibilities look to remain VFR at all three terminals, but, with southerly winds, smoke from fires burning in New Mexico could effect visibility from this afternoon until tomorrow morning, especially in the vicinity east of KPUB and KCOS. Thunderstorms developing east of KCOS and KPUB this afternoon could also lead to outflow winds and virga on the plains, but right now we`re not expecting any impacts to terminals. Diurnal wind trends will try to set up overnight, causing a period of low level wind shear to be possible from about 05Z-12Z at KCOS and KPUB and 11-15Z at KALS. Mixing will begin early, as strong westerlies set in for tomorrow between 15-18Z. Areas of blowing dust could impact terminals tomorrow morning, as early as 14Z, but have left mention of this possibly out until confidence is higher. && .PUB WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 10 PM MDT this evening for COZ220>237. Red Flag Warning from 7 AM to 10 PM MDT Thursday for COZ220>237. && $$ SHORT TERM...STEWARD LONG TERM...ERH/MW AVIATION...EHR/MW