Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/30/23


Area Forecast Discussion
National Weather Service Columbia SC
741 PM EDT Sat Apr 29 2023 .SYNOPSIS... A strong low pressure system deepens as it moves towards the area from the Gulf Coast region tonight into Sunday, bringing periods of rainfall to the area. Dry conditions and cooler than normal temperatures expected early next week as troughing dominates the weather over the eastern CONUS. && .NEAR TERM /THROUGH TONIGHT/... Strong upper shortwave currently moving through the Lower Mississippi Valley, ahead of which some upper energy currently approaching our region in a SW flow aloft, leading to moisture increase and a batch of showers and some thunderstorms currently approaching our FA from the SW. This activity will move NE into the W FA this evening, and across the remainder of the FA later tonight. A surface low is progged to develop over the N GOMEX and track NE into our FA late tonight, leading to some additional precipitation affecting our FA late tonight into early Sunday. Limited instability but significant shear leads to some severe weather concerns. The southern half of our FA is outlooked in a MRGL risk of severe weather per latest SPC Day 1 outlook. && .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... Sunday: Activity associated with the aforementioned cold front should be ongoing as day breaks. The limited severe threat shifts to the northern half of the forecast area, particularly the northeastern portions for the mid morning hours as the cold front progresses northeastward. A third round of precipitation associated with the passage of the upper low is expected for midday into the afternoon. Activity with the upper low passage could also produce some stronger storms, with damaging wind and large hail being the main threats. Like with the earlier morning activity, confidence is low in any severe weather occurring. Behind the outgoing system, gusty west to southwest winds are expected to develop. Winds are anticipated to gust to 25 to 30 mph at times from mid morning into the evening, which has prompted a Lake Wind Advisory. Sunday night: Cold advection will spread over the region Sunday night in the wake of the departing upper trough. High pressure will build in from the west as another expansive closed upper low establishes itself over the eastern Great Lakes and Ohio Valley region. Much drier air will move into the region with PWATs falling below a half inch. Winds should remain breezy through the evening with a bit of a pressure gradient and deep mixing with strong low level westerly winds. Despite clearing skies the mixed boundary layer with winds staying up should limit radiational cooling but cold advection looks to support lows in the upper 40s to lower 50s. Monday through Tuesday night: Sensible weather should be relatively benign this period with a continued dry and stable air mass in place. Ensemble guidance continues to show a persistent upper closed low over the eastern part of the country with PWATs remaining below a half inch, so no precipitation is expected. Winds will be the main concern both Monday and Tuesday during the day as 850mb winds will be from the west around 35-40 knots and with deep mixing expected each day, breezy conditions are expected. Surface winds should be 15 to 20 mph with gusts as high as 35 mph both days and a lake wind advisory may be needed. Depending on total rainfall through the weekend, there could be some fire weather concerns developing by Tuesday due to significant dry air and breezy conditions if fuel moisture lowers enough. Below normal temperatures expected this period with highs ranging from the upper 60s to mid 70s and lows in the 40s. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... Ensemble and deterministic guidance in reasonable agreement with the overall pattern. A shortwave will round the base of the lingering upper low over the eastern part of the country pushing a dry reinforcing front through the region late Tuesday night and Wednesday morning. The upper low will then shift eastward off the New England coast as flat upper ridging occurs over the Plains states allowing some shortwave energy to move into the region in northwesterly flow aloft by Friday into Saturday, bringing an increase in chances of rain. Dry weather is expected Wednesday and Thursday with cooler than normal temperatures on Wednesday and moderating temperatures back closer to normal on Thursday with continued warming on Friday. No significant weather expected at this time. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... VFR into this evening before IFR becomes likely overnight. Regional radars showing area of rainfall just south of the CSRA terminals of ags/dnl at issuance time. This is right in line with the latest hrrr and near term models for the most part. Guidance consistent with bringing rainfall northward and near cae/cub/ogb by 01z, with the rain then overspreading all taf locations through 06-07z. Some rumbles of thunder possible along with the rain, so mentioned cb when the heavier more persistent rainfall moves into the area. After 07z, there may be a break overnight in the rainfall, with another batch then moving in closer to 12z. Drier air not expected to really move until early Sunday afternoon. Until then, plenty of cloud cover will remain. Conditions start off vfr, then do drop down to mvfr after 07z when the first batch of rain moves out. A continued lowering to ifr will be possible towards 12z with the next round of rainfall. A return to vfr conditions should occur by 19z at all locations as drier air moves in and winds increase mixing. In addition to the rain and clouds, can not completely rule out low-level wind shear towards daybreak. Due to low confidence though, will not include at this time. As the activity begins to wind down on Sunday, west to southwest winds gusting to 20 to 25 kts become likely. EXTENDED AVIATION OUTLOOK...Sunday night, dry air begins to limit chances for restrictions lasting through the end of the forecast period with the exception of early morning fog at OGB and AGS. && .HYDROLOGY... Runoff from recent widespread heavy rain, with totals around 3 to 5 inches, Wednesday through Thursday night, across the Upstate and Piedmont of SC, and the Foothills and Western Piedmont of NC, will continue to flow downstream and provide river flooding at several forecast points along the Enoree, Saluda, and Congaree Rivers. Details available on our website. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...Lake Wind Advisory from 8 AM to 8 PM EDT Sunday for GAZ040- 063>065-077. SC...Lake Wind Advisory from 8 AM to 8 PM EDT Sunday for SCZ016-018- 020>022-025>031-035-037-038-041-115-116-135>137. && $$
Area Forecast Discussion
National Weather Service Indianapolis IN
926 PM EDT Sat Apr 29 2023 .Forecast Update... Issued at 926 PM EDT Sat Apr 29 2023 - Chance for showers overnight. - Cool Surface analysis late this evening shows deep low pressure over the UP of Michigan. From this low, a cold front extended southeast across MI and then southwest across Northern Indiana to Central IA. An area of showers and clouds was found in the wake of the front over IL and NE MO. Cyclonic flow remained across Central Indiana. GOES16 shows waves of clouds, some of which have showers, pinwheeling around the nearby upper low. Cool westerly surface flow was in place across Central Indiana, with temperatures in the 50s. Stronger NW flow with a tighter pressure gradient was found in the wake of the cold front over IA and WI. Tonight the upper low is expected to sag southward across MI, keeping cyclonic flow in pace across central Indiana. This flow will aid the progression of the cold front across Central Indiana, as it will pass across the forecast area during the overnight. Rain showers and cloud cover associated with the cold front, as seen over western IL, are expected to pass across the forecast area in the wake of the cold front. HRRR is on board with this, showing showers moving across the area. Forecast soundings and time heights also are on board, showing lower level saturation as these features pass. Thus will aim for some chance pops for light precipitation as the cold front passes. Precipitation amounts should be light, with the best coverage in place across the northern half of the forecast area. Given the temps in the wake of the cold front, lows in the lower to middle 40s will be on the mark. && .Short Term...(This evening through Sunday) Issued at 248 PM EDT Sat Apr 29 2023 As of this afternoon, a large trough is diving down out of Canada and is expected to be the primary factor determining our weather for the next few days. At the surface, southwesterly flow ahead of this feature has allowed temperatures to warm up to near 70. That will be short-lived, unfortunately, as a cold front associated with the trough advances southward. Showers and thunderstorms are possible today, primarily focused near and along the front. Very steep low-level lapse rates and sufficient moisture should allow enough instability for a few thunderstorms capable of briefly gusty winds. Severe thunderstorms are not expected, though a few gusts to 45mph are certainly possible. Any lingering shower or storm should come to an end as the front exits into Ohio. Behind the front, winds become northwesterly and cold air advection takes hold. Temperatures within the core of the upper-level low are expected to be rather chilly, roughly between 0C and -5C for the next few days. As such, expect cooler than normal weather through tomorrow. Lows tonight should dip into the low 40s and rebound into the low to mid 50s tomorrow before rapid stratocumulus development. A vort max rotating around the trough should swing through tonight, bringing a secondary round of showers. Instability is very limited, so not expecting thunder with this. Thunder chances return after sunrise, however, as diurnal heating generates modest amounts of CAPE given the very cold air mass aloft. Thermal profiles suggest that graupel or small hail may be possible within some of the stronger showers or storms. Additionally, steepening lapse rates should allow efficient downward momentum transfer tomorrow, leading to wind gusts reaching 25 to 30kts at times. && .Long Term...(Sunday night through Saturday) Issued at 248 PM EDT Sat Apr 29 2023 The beginning of the long term will be heavily influenced by a nearly cutoff upper level low, of which will remain within the perifery of Indiana through Tuesday. Synoptically, an Omega Block pattern will set up over the CONUS, reinforcing ridging over the Mountain-West. This will elongate and stetch upper level troughing east of the Mississippi River leading to below seasonal temperatures for much of this area. Central Indiana will origonally be within a martime polar-like air mass as moisture wraps around the stagnant low. This should lead to cool, semi-wet conditions. Forcing will be marginal, but sporatic light showers within low cloud cover are likely Monday and Tuesday. Prolonged cloud cover will limit diuranl temperature swings, keeping surface temperatures between the upper 30s and mid 50s, witfh a few SW locations in the upper 50s. By Tuesday night, slight progression of the ridge will allow for a drier airmass to advect over the region. This should allow for skies to clear sometime Tuesday night, leading to more effeceint diurnal cooling and colder temperatures Tuesday night into Wednesday f morning. Freezing temperatures Wednesday morning will be possible. Winds will be fairly strong within a fairly steep pressure gradientf over the area, although a suppressed PBL should limit gusts slightly. The second half of the week should slightly warmer as the ridge begins to influence the Great Lakes Region. Temperatures will still be slightly below seasonal within NW flow, but the mostly dry air mass will create near dry adiabatic PBLs within high downwelling SR of early May. Isolated showers are possible Friday into Saturday associated with a weak low level disturbance. Expect highs in the mid to upper 60s with overnight lows closer to the dew point in the upper 30s and low 40s Wednesday through Saturday. . && .Aviation...(00Z TAF Issuance) Issued at 701 PM EDT Sat Apr 29 2023 Impacts: * Waves of showers with isolated thunderstorms tonight and again Sunday afternoon. * Mainly VFR conditions tonight with MVFR conditions Sunday. * Gusty winds around 25kts on Sunday. Discussion: Radar shows and area of convective showers pushing to the southeast of the Taf sites. These showers are expected to end/exit within the first few hours of the TAF period due to the loss of daytime heating and propagation. Broad cyclonic flow will remain across the TAF sites through this TAF period due to the deep upper low found over WI. This feature is expected to remain across the Great Lakes through the TAF period, allowing waves of upper support to pinwheel across the TAF sites within the next 24-36 hours. Models suggest a wave pushing through overnight. Precipitation over IA at the moment is associated with this wave. We have included a period of VCSH overnight with low VFR cigs as this passes. In the wake of this system MVFR Cigs are expected to arrive on Sunday, with another wave suggested to pass on Sunday afternoon. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ Update...Puma Short Term...Eckhoff Long Term...Updike Aviation...Puma
Area Forecast Discussion
National Weather Service North Platte NE
1047 PM CDT Sat Apr 29 2023 ...Aviation Update... .SYNOPSIS... Issued at 236 PM CDT Sat Apr 29 2023 Key Messages: Key Messages in short term: *Critical fire weather concerns continue this afternoon and tomorrow *Gusty winds remainder of this afternoon and north central NE Sunday Key Messages in the long term: *Above normal temperatures Wed. and Thu. *Elevated to near critical fire weather concerns through mid-week && .SHORT TERM...(This evening through Sunday night) Issued at 236 PM CDT Sat Apr 29 2023 Did do some minor tweaks to the rest of the afternoon forecast. Adjusted temperatures a few degrees warmer and increased winds slightly across the south where felt there could be some better mixing through early evening that would mix down some stronger gust. For Sunday, did trend winds toward the 90 percentile to blend more closely with the RAP and NAM models, mainly across southwest into north central Nebraska, where there was a slight increase. Don`t expect to see the amount of mixing or the strong winds aloft, as seen today, however it will still remain fairly breezy across north central Nebraska back into portions of southwest Nebraska, with the potential for gust of 35 mph or greater. The cooler air mass behind the front will keep temperatures cooler on Sunday with highs in the mid 50s to low 60s, which is below normal. Despite the cooler temperatures Sunday there is still the potential for near-critical to critical fire weather concerns, see fire weather discussion below for additional information. .LONG TERM...(Monday through Saturday) Issued at 236 PM CDT Sat Apr 29 2023 The High Plains will continue to see a upper level northwest flow as they are wedged in between a strong upper level low to the east across the Great Lakes Region and a ridge to the west across the Rockies into the Canadian Prairie for the beginning of the week. As the upper level low across the Great Lakes continues to move eastward, the ridge to the west begins to expand east into the High Plains region, with temperatures reaching the 70s by Tue. and 80s by Wed. Temperatures will remain above normal for Thursday as well with highs in the mid to upper 70s. The airmass on Tuesday and Wednesday and even into Thursday will be fairly dry and thus will present some elevated to near- critical fire weather concerns for those days, will need to continue to monitor. A weak disturbance may move through Wed. night into Thu. bringing the potential for some light showers. However, although there will be some return flow of moisture with the system, would not expect any wetting rains, but could see some spotty light rain showers, at this time confidence is low to see much coverage in precip. There will be another potential for precip towards the end of the period as the upper level low spinning across the west coast earlier in the week finally moves ashore and into the central CONUS, again though, confidence is low at this time in the way of precip coverage for the area, but spotty showers may be possible. && .AVIATION...(For the 06Z TAFS through 06Z Sunday night) Issued at 1046 PM CDT Sat Apr 29 2023 VFR conditions will continue to prevail the rest of tonight and through the day Sunday. Winds will go down some tonight but then pick up again from the north to northwest Sunday. Gusts Sunday afternoon will again be in the 25-35 kt range. && .FIRE WEATHER... Issued at 236 PM CDT Sat Apr 29 2023 The combination of strong winds, warm temperatures and low humidity will result in the near-critical to critical fire weather concerns to continue through the remainder of this afternoon into the early evening. For the overnight hours, the recovery will be poor across western and southwest Nebraska where overnight humidity values will range from 55% to 65% percent. This will then result in setting up another day of critical fire weather concerns with the combination of poor overnight recovery, low min RH and gusty winds for Sunday afternoon and early evening. Critical fire weather concerns will generally be across fire weather zone 219, with near-critical concerns across fire weather zones 210 and 209. A Red Flag warning has been issued for Sunday, for fire weather zone 219, as confidence is greatest for this zone to meet RFW criteria. Winds in this area will be around 20 mph or more out of the north northwest, with gust up to 30 mph, in combination of low RH values as low as 14 percent. && .LBF WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from 1 PM to 8 PM CDT Sunday for NEZ219. && $$ SYNOPSIS...Gomez SHORT TERM...Gomez LONG TERM...Gomez AVIATION...Taylor FIRE WEATHER...Gomez
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1005 PM EDT Sat Apr 29 2023 .SYNOPSIS... High pressure will briefly build into the area today bringing quieter conditions to the region before another strong and wet storm system moves up the East Coast Sunday into Monday. Drier and cooler weather is then expected through mid next week as high pressure builds into the Eastern CONUS. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... As of 8:15 PM Saturday...All is quiet across the FA with CAMs in agreement for the first round of convection to start in our southern counties and offshore waters between 3-6Z. The 00Z sounding shows impressive values of CAPE, shear, and SRH. Near the time of convective initiation, RAP analysis shows 500-1000 J/kg of MLCAPE, 45-50 kts of effective bulk shear, and SRH values around 100 m2/s2. These conditions could be favorable for supercells and/or organized convection with strong updrafts through the early morning hours. The potential for isolated tornadoes, damaging wind gusts, hail, and heavy rain are all on the table. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... As of 10 PM Saturday...Only minor tweaks to lower the PoPs behind the first round of showers and thunderstorms. As stated in the previous discussion, this could allow instability to rebuild for the second round of potentially severe storms tomorrow afternoon. Previous Discussion...As of 1630 Saturday...Vigorous shortwave becomes negatively tilted while pivoting around broad cyclonic flow over the eastern CONUS, driving rapid surface cyclogenesis over the Carolinas and mid- Atlantic on Sunday posing multiple hazards. Heavy rain and thunderstorms, particularly over the Outer Banks, will be ongoing tomorrow morning as the surface low lifts along the I-95 corridor. Widespread model consensus shows showers and tstorms likely ongoing during the morning, especially in the vicinity of the surface low as it lifts north. It is during this period that severe potential will be maximized as surface CAPEs surge north of 1000 J/kg, coupled with effective shear of 40-60 kts thanks to stout 850mb and 500mb jets. This will also be the most favorable time for potential tornado development with any discrete cells. SPC has our area in a Slight Risk of severe thunderstorms with an isolated tornado and damaging winds being the main threat. Have lowered PoPs behind this initial wave of precip when some clearing is possible, which would allow instability to rebuild for the next round of convection in the afternoon and evening. The next wave of convection, driven by the cold front behind the low, is expected to cross the region from west to east during mid- afternoon. Some instability will likely linger across the region despite considerable atmospheric turnover with the morning low, and a few strong thunderstorms are again possible. By this time, low- level wind profiles will be more unidirectional favoring damaging winds as the primary hazard but there will be a nonzero threat for an isolated tornado or hail should the stronger instability and cooler air aloft be realized. Outside of convection, a brief but potent surge of south to southwesterly winds is expected, especially in the afternoon as the low lifts north. Gusts pushing 40+ mph are probable across portions of the Outer Banks. The surge, while brief, could lead to some minor soundside flooding issues north of Cape Hatteras. A coastal flood advisory has been issued for these areas. See the TIDES/COASTAL FLOODING section for details. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... As of 1645 Sat...The low that impacted the area SUnday occludes and lingers over the Great Lakes for the first half of the work week before high pressure eventually wrestles back control, leaving eastern North Carolina cooler and drier for the remainder of the period. Monday through Friday...Primarily dry and cooler than average conditions hold over eastern North Carolina through the rest of the period as the surface low occludes over the Great Lakes and meanders over the region through Wednesday. While the low stays in place, healthy southwest to westerly winds are expected during the afternoons with gusts up to 25 kt. The strongest winds are likely on Tuesday ahead of a surface trough pivoting around the low, with gusts to 25-30 kt possible over the coastal plain. When coupled with much lower dew points in the upper 30s to low 40s, RHs will fall well into the 30% range raising fire weather concerns. By Thursday, the surface low will have lifted out over the North Atlantic allowing high pressure to take more dominant control, quickly shifting offshore and aiding in moist southerly return flow. By the end of the week, temperatures will have rebounded to seasonal norms after days of being 5-10 degrees below average. The next system to watch will be at the end of the week as weak low pressure zips along a stalled front. Typical model differences preclude mentionable PoPs in the forecast for this cycle. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... SHORT TERM /through 00Z Monday/... As of 8:15 PM Saturday...All TAF sites expected to remain at VFR until showers and thunderstorms start to develop near 06Z causing a drop to MVFR CIGs. During heavier rain, some visibilities could briefly drop to MVFR/IFR. A second round of rain and thunderstorms is expected tomorrow afternoon along with gustier SW winds around 25 kts. LONG TERM /Sunday through Wednesday/... As of 400 AM Sat...Low pressure continues to lift across the area tomorrow bringing multiple waves of showers and thunderstorms and extended periods of sub-VFR conditions. A few strong thunderstorms are possible particularly in the morning and early afternoon. By late Monday, the low departs with VFR conditions returning and remaining dominant for the rest of the period. && .MARINE... SHORT TERM /through Tonight/... As of 1645 Saturday...High pressure resides over the waters through this evening before a strong area of low pressure approaches the waters from the SW late tonight and produce strong winds, building seas, and tstorms. Light and variable winds, predominantly out of the SE currently become SSEerly 10-15 kt through this evening with seas generally subsiding through the evening, 5-6ft N of Ocracoke Inlet, 4-5 S. SCAs in place for linger 6ft seas continue stepping down, Nern waters 0Z, Central waters 6Z. As strong low pressure approaches late tonight Serly winds over the Sern and Central waters will increase to 15-25 kt with seas rebuilding to 5-7 ft 9-12Z Sunday, kicking off an extensive period of hazardous marine conditions, particularly for coastal waters. Strong low pressure will continue to lift across the region tomorrow afternoon with a surge of Serly to SWerly winds. Sustained winds of up to 30-35 kt are expected with gusts as high as 40 kts at times. Within passing showers and thunderstorms, higher winds are possible. This will rapidly build seas, up to 10-13 ft for Raleigh Bay and outer Onslow Bay by sunset on Sunday. North of Cape Hatteras, seas of 8-11 feet are anticipated particularly beyond 10-15 nm. Existing Gale Watches have been upgraded to Gale Warnings and SCAs have been issued for all remaining inland waters. LONG TERM /Sunday through Wednesday/... As of 1645 Sat...Persistent SCA winds will continue at least through Wednesday as the surface low lingers over the Great Lakes keeping the pressure gradient tight over the waters. Beyond tomorrow, the strongest winds are expected on Tuesday ahead of an approaching coastal trough with southwesterly winds gusting up to 30 kt. This will keep seas up to 6-8 feet particularly south of Oregon Inlet, through Wednesday afternoon. && .FIRE WEATHER... As of 1700 Saturday...Behind strong low pressure system Monday morning, cooler and drier high pressure will move into the area through most of next week. While this occurs, a large and occluded low pressure system will sit over SE Canada, and keep a strong pressure gradient intact across the Carolinas through Wednesday. RH values will drop to at least 30%-35% each afternoon, while winds remain strong at 15-20 mph with gusts 25-30 mph. The strongest winds are expected Tuesday afternoon ahead of a surface trough pivoting around the parent low. Deep mixing may promote even stronger wind gusts at times. && .TIDES/COASTAL FLOODING... As of 1700 Saturday...A brief but potent surge of southerly to southwesterly winds is expected late Sunday morning into the afternoon as strong low pressure lifts across the coastal plain. Gusts could reach as high as 40 mph particularly along the Outer Banks. Despite the short duration of the winds, some minor soundside flooding of 1 to 2 feet is possible with the most vulnerable areas being the Outer Banks north of Cape Hatteras. Coastal Flood Advisories have been issued for these areas. In addition to flooding, dangerous surf conditions are likely to develop on Sunday and linger into Monday. The most vulnerable beaches will be Sern facing beaches, predominantly from Cape Hatteras south, and could lead to overwash and dune erosion. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...Beach Hazards Statement through Sunday evening for NCZ195-196- 199-203>205. Coastal Flood Advisory from 8 AM to 10 PM EDT Sunday for NCZ195-196-199. High Surf Advisory from 11 AM Sunday to 5 AM EDT Monday for NCZ195-196-199-204-205. Coastal Flood Advisory from 11 AM Sunday to 2 AM EDT Monday for NCZ203-205. MARINE...Small Craft Advisory from 11 AM Sunday to 7 AM EDT Monday for AMZ131-230. Gale Warning from 2 PM to 8 PM EDT Sunday for AMZ135. Small Craft Advisory from 8 AM to 8 PM EDT Sunday for AMZ136- 137-231. Small Craft Advisory from 9 AM Sunday to 10 AM EDT Monday for AMZ150. Small Craft Advisory until 2 AM EDT Sunday for AMZ152-154. Gale Warning from 10 AM to 10 PM EDT Sunday for AMZ152-154. Gale Warning from 10 AM to 9 PM EDT Sunday for AMZ156-158. && $$ SYNOPSIS...MHX NEAR TERM...CEB/OJC SHORT TERM...MS/CEB/OJC LONG TERM...SGK/MS AVIATION...CEB/OJC MARINE...MS/CEB FIRE WEATHER...MHX TIDES/COASTAL FLOODING...MHX
Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
1057 PM CDT Sat Apr 29 2023 .DISCUSSION...(This evening through Saturday) Issued at 254 PM CDT Sat Apr 29 2023 KEY MESSAGES: - Rain is expected to change over to snow overnight in western WI, with minor accumulations on grassy and elevated surfaces possible. - Strong northwest winds, with gusts to between 40 mph and 50 mph will be possible Sunday west of the Mississippi River. - Next week continues to look dry and mild, with highs in the 70s possible west of the Mississippi River on Wednesday. While stratiform cloud cover and light rain continue to plague portions of western WI, clearing to the west has allowed a cumulus field to develop in MN. Radar imagery shows scattered diurnal showers present within this cumulus field that will move south- southeast as the afternoon progresses. Only the central portion of MN is shower-free where the stronger subsidence that was mentioned in this morning`s discussion has been realized. Thus, expect scattered showers into this evening basically everywhere aside from central to southeastern MN. CAMs forecast these showers dying off this evening with the loss of daytime heating. Our pesky low pressure system will continue to spin over the Upper Great Lakes through Sunday and, just when you think it couldn`t get any more annoying, deepen. Another jetstreak will round the base of the trough and the accompanying lift ahead of it will allow for mass evacuation within the low. This will do 2 things: 1. Wrap-around precip to the west of the surface low (eastern MN and WI) will restrengthen tonight and persist through most of Sunday. While surface temperatures will be above freezing tonight (mid 30s), very cool thermal profiles should allow for snow to mix in the eventual rain. This is most likely as one heads farther east into central WI where the coldest air will reside. Here, 1 to 2 to perhaps up to 3 inches of snow may accumulate on elevated on grassy surfaces by Sunday morning. Snowflakes will be less likely into eastern MN but cannot rule out a flake or two as winter`s last gasp occurs. Precip should change over to all rain and slowly trudge east as Sunday`s temperatures warm into the mid to upper 40s. 2. Northwesterly winds will greatly increase due to the strengthening pressure gradient. Sustained surface winds on Sunday will be at least 20 knots across the entire region with strongest winds in western MN (25-30 knots). With gusts at least another 10 knots on top of sustained values, a Wind Advisory may be needed for portions of MN Sunday. One possible complication is that RAP forecast soundings show maximum boundary layer lapse rates (strongest daytime heating) don`t coincide with the timing of the strongest LLJ. Thus, winds may not reach their full potential. Chances for rain showers (mixing in with some snow) continue Monday night in western WI as lows fall to the low to mid 30s area-wide. Monday`s weather will be similar to Sunday`s, albeit with shower chances slightly farther east, highs warmer in the upper 40s to mid 50s (warmest west), and winds slightly weaker. We should finally be rid of the low pressure system by Tuesday with a warm up towards more seasonable temperatures following. Guidance suggests Wednesday will be the warmest day with highs exceeding 70 for most of MN. For the rest of the period, highs should generally be in the upper 50s to mid 60s and lows in the 40s. As for precipitation, NBM PoPs are very low the remainder of the period as a rex block pattern unfolds. Blocked ridging over the central CONUS and Canada should keep any strong synoptic systems from encroaching the Northern Plains. Thus, any precipitation will likely have to come from small-scale features which tend model predictability tends to degrade greatly with in respect to time. && .AVIATION...(For the 06Z TAFS through 06Z Sunday night) Issued at 1057 PM CDT Sat Apr 29 2023 Light snow will has developed over northeast WI and will build southwestward overnight to EAU by 08Z, RNH by 09Z, and possibly MSP by 11Z. Biggest impact will be to visibilities which could drop to IFR levels. Strong northwest winds will develop late tonight and early Sunday morning with gusts of 35-43 kts expected west of the Mississippi River through the day. KMSP...Another round of light precip as rain/snow should move in between 11-14Z. Then, scattered showers likely continuing for the rest of the day. Winds should increase markedly as the precip moves in late tonight. /OUTLOOK FOR KMSP/ MON...VFR. Chc MVFR cigs. Wind NW 15-20G30kts. TUE...VFR. Wind NW 10-15G20kts. WED...VFR. Wind SW 5-10kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...CTG AVIATION...Borghoff
Area Forecast Discussion
National Weather Service Pocatello ID
133 PM MDT Sat Apr 29 2023 .SHORT TERM...Tonight through Sunday night. Upper ridge axis sharpens and shifts overhead during the day Sunday. Southerly flow develops during the day Sunday and continues into Monday. The GFS and Hi-Res derivatives show mid level moisture streaming into the central mountains and potentially the Magic Valley, with the HRRR also showing a slight hint of convective development. At this time, believe this is overdone with little support in the NAM and other high-res model solutions and thus also the HREF, though wouldn`t be surprised to see a sprinkle or two and locally gusty winds. Temperatures and subsequent ongoing snow melt remain the main concerns, with temperatures surging into the 70s and 80s across many lower elevation areas and temperatures remaining above freezing overnight especially in lower elevations. DMH .LONG TERM...Monday through Saturday. Omega block in place for first half of the week. Our weather will be mainly dominated by a ridge which will produce temperatures roughly 15 degrees above normal. This will likely accelerate snowmelt with worsening flooding conditions likely. A low pressure area stationed near the central California coast will push enough moisture into central and east Idaho to fuel isolated showers and thunderstorms. This will remain the case until late week when the ridge weakens and the low is able to move further inland. Nearly all model solutions show this occurring but differ significantly in how this will occur. So confidence in cooler (closer to normal) temperatures with widespread precipitation late week is high. However, confidence with regard to timing, precipitation amounts and how that will factor into the flooding situation is low. 13 && .AVIATION...VFR conditions likely today with mainly upslope/upvalley winds today becoming downslope/downvalley tonight. A few models are indicating an isolated dry shower or thunderstorm near KSUN this afternoon. Will continue to monitor to see if this develops, but at this point confidence is not strong enough to mention in TAF. 13 && .HYDROLOGY...Strong warming trend continues into next week. Overnight lows will remain above freezing for most lower elevations, even up to some mid slope areas, and daytime highs will remain very warm. Runoff is expected to increase into creeks and streams, and flooding of low-lying fields and flood-prone areas is likely. Snowmelt forecasts from NOHRSC indicate around or over an inch of snow-water melt through tonight, then another inch on Sunday. Temperatures jump significantly Monday, and the forecasted snow-water melt from NOHRSC jumps to 2" in some areas. River forecasts continue to show a strong response. The Big Wood at Hailey remains within or very near action stage and could reach flood stage as early as Monday night. The Little Wood above High 5 Creek continues to flirt with flood stage every night with minor flooding upstream, and is trending upwards. The Portneuf River remains a significant concern, already into minor flood with a very high probability of reaching moderate flood Sunday evening. Latest projections give the Portneuf at Pocatello a roughly 60% chance of exceeding MAJOR flood Stage. Additional concerns are starting to reach the Portneuf further upstream at Topaz, which may necessitate stretching the Flood Warning further upstream from the current polygons. The Bear River at Border currently looks to reach flood stage Monday. Existing FLOOD ADVISORY and FLOOD WARNING products will remain in place currently, with potential for further upgrades and additions depending on how the rivers react overnight to today`s temperatures. Otherwise, the AREAL FLOOD WATCH remains in place with one addition. Have added the Stanley area to the FLOOD WATCH in anticipation of potential concerns along Valley Creek and further upstream into the Stanley Basin. If temperatures rise warmer than anticipated, flooding risk may continue to escalate area-wide. DMH && .PIH WATCHES/WARNINGS/ADVISORIES... Flood Watch through Tuesday afternoon for IDZ056>059-061>068-072-075. && $$
Area Forecast Discussion
National Weather Service Raleigh NC
918 PM EDT Sat Apr 29 2023 .SYNOPSIS... Low pressure over the lower Mississippi Valley region will track NE across NC Sunday morning. The associated cold front will track east across NC Sunday afternoon and evening, then offshore Sunday night. High pressure will bring drier and much cooler conditions early to mid week. && .NEAR TERM /THROUGH TONIGHT/... As of 918 PM Saturday... The latest data analysis indicated an arc of showers (thunderstorms mostly offshore of the SC coast) associated with the old MCV/convective complex to our south. The showers extended from Atlanta to Charleston moving north-northeast. In addition, the cold front and surface low pressure were located over the lower MS valley extending into AL. Although the dew points have been coming up and the boundary layer moisture increasing, central NC remained stable this evening with a thickening of high cloudiness. It appears the HRRR is doing a better job with the arc of showers to our south that is expected to push northward across our region later tonight. The stronger convection is expected to remain along the coast or in the Gulf Stream just offshore. Low pressure is expected to translate to central or SE GA late tonight, then track NE across SC/NC Sunday morning into the early afternoon. It appears that HRRR and operational models are honing in on a warm front to push into the Coastal Plain later tonight and early Sunday as the first band of showers moves north and brings a lull in activity here. Additional convection is expected to form near and along the low pressure track Sunday morning. Bottom line, this first band of showers/iso thunder is not expected to have severe weather associated with it. We will have to wait until the next round arrives mid to late morning for the severe potential to increase. The warm frontal position will be critical to the placement of severe storms Sunday. The Coastal Plain and Coast appear to be most at risk, with the Piedmont possibly too stable. We will simply bring the chance of showers in a bit quicker with this update tonight. Otherwise, the forecast rational has not changed. Lows in the upper 50s to mid 60s. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... As of 250 PM Saturday... ...There is a Slight Risk for severe weather on Sunday across eastern NC... On the larger scale, a compact shortwave rounding the base of the upper low over MN/WI, and its associated surface low will lift north across the central NC on Sunday. Multiple rounds of storms are possible late tonight through Sunday afternoon. The first will be associated with a convective impulse lifting out of the Gulf Coast states today, followed closely by the northward/inland push of the warm front associated with the aforementioned surface low and then then upper shortwave and trailing cold/effective front. With strong deep layer shear and forcing for ascent, the limiting factor will be destablization during the day on Sunday. First, it appears the MCV will race north across the area tonight and exit to he northeast well before 12z. It is possible that the subsidence in the wake of the MCV and any associated convection could help to initially limit storms in the 12-15Z time frame when the warm front and more theta-e rich are poised to surge into the coastal plain, and hodographs are most strongly curved. Given this, confidence in the early morning severe threat is low, but this is likely when any low-end tornado threat would be greatest. Additional destablization from daytime heating is also questionable through Sunday afternoon given widespread early cloud cover, only minimal intrusion of dry air ahead of the shortwave, and muted dewpoints in the upper 50s to lower 60s...except for areas east of I- 95 where dewpoints are progged to reach the upper 60s. Models generally suggest 1000-1500 MLCAPE near and east of US 1. That said, the surface low is forecast to strengthen to near 990mb over central NC as the shortwave becomes negatively tilted. The most vigorous pressure falls are forecast as the low lifts toward the northern coastal plain, so if there is an area where elongating hodographs and gradual destablization overlap with the best deep layer lift, it may be northeast of the Triangle after 15Z. The primary threat during the day will be damaging straight line winds and large hail. Convection should be departing the northeast CWA by 21Z, with the trailing cold front forecast to swing through the area between 00Z and 06Z Monday (Sunday evening). Cannot rule out some isolated showers with the front, but deep layer lift won`t be as strong and moisture will have moved off to the northeast as well. Modest pressure rises in the wake of the departing low should maintain some decent wind gusts of 20-25kt well on into the late evening and early overnight period before finally dying off Monday morning. Lows in the upper 40s and lower 50s. Regarding flooding potential...a couple rounds of showers and storms in the east, with another batch of precip in the western Piedmont likely during the day as the upper wave crosses the area should produce another 0.5" to 1.5" of rainfall, with some likely higher amounts. The western Piedmont received over an inch of rain early Friday, so those areas are a bit primed, but any risk of flooding should be tied to multiple rounds over one location or training of storms, so the flood threat is generally low. && .LONG TERM /MONDAY THROUGH SATURDAY/... As of 300 PM Saturday... ...Cool and Windy for the First Half of the Work Week... Omega block over the CONUS will maintain an amplified upper low over the Great lakes through mid-to-late week, resulting in below normal temperatures and generally dry conditions under westerly flow. It`s possible that a rippler or two rounding the base of the upper trough could bring some periods of cloudiness and light showers or sprinkles, especially around midweek as a reinforcing cold front is forecast to push into the area, but areas east of the Appalachians are forecast to remain mostly dry in the absence of better deep moisture. The upper jet will be positioned overhead during this period and should translate to gusty winds east day and perhaps some fire weather concerns by Wed after a couple days of drying out. Highs will be in the mid 60s to lower 70s Mon-Wed, warming Thu/Fri with the a lot of uncertainty as to whether another system with precip will reach the area Fri/Sat or not. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... As of 704 PM Saturday... VFR CIGS will lower as showers move into the southern part of NC late this evening and through the region overnight. Expect IFR to LIFR conditions later tonight through mid-morning Sunday with showers/fog. Another round of showers and isolated thunderstorms is expected Sunday morning through the early afternoon, then scattered thunderstorms ahead of the cold front Sunday afternoon and early evening. Beyond 00Z Monday: A return to VFR conditions are expected Sunday night. These conditions should late though much of the upcoming work week. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Badgett NEAR TERM...Badgett SHORT TERM...BLS LONG TERM...BLS AVIATION...Badgett
Area Forecast Discussion
National Weather Service Salt Lake City UT
347 PM MDT Sat Apr 29 2023 .SYNOPSIS...High pressure will bring warming temperatures more reminiscent of early summer through early next week. A cooler, unsettled pattern is expected to develop Thursday, and continue into next weekend. && .DISCUSSION...An expansive mid level ridge encompasses much of the western CONUS this afternoon, which is allowing for sunny skies and a considerable warming trend. RAP 700mb analysis shows temperature ranging from 6C across northern and eastern UT, to 8C across the southwest. Mixing this warmer air mass to the surface has allowed temps to reach the mid to upper 70s along the Wasatch Front this afternoon, and around 90 in the St George area. This ridge will shift east slightly on Sunday, allowing 700mb temps to approach 10C across northern UT, and 11C across the south. This will push max temps in to the low to mid 80s along the Wasatch Front, while a more muted warming trend across southern UT pushes max temps 2-4 degrees warmer. This warming will continue to fuel snowmelt across the area, allowing rivers, creeks and streams to continue running cold and swift. Flood watches remain in effect for mainstem rivers forecast to approach or exceed flood stage heading into early next week. The mid level ridge axis will shift east of the forecast area early next week, as an upper low currently spinning off the Pacific coast begins to spread inland. Increasing southerly flow ahead of this low will result in windy conditions Monday afternoon across western UT, and mid level moisture coupled with weak large scale lift will bring a small threat for high based convection across northern UT Monday afternoon and evening. Otherwise the air mass across the forecast area will remain very warm, with 10C 700mb temps maintaining 80 degree temps across the Wasatch Front, and near 90 around the St George area. The upstream upper low is forecast to slowly spread inland during the latter half of the upcoming week, allowing a couple of shortwaves to lift across the forecast area. The initial wave ejects across the eastern Great Basin Thursday bringing cooler temperatures and a band of precipitation along the associated baroclinic zone. A second wave follows late Friday through Saturday bringing a re-enforcing shot of cooler air along with another chance of precipitation area-wide. && .AVIATION...KSLC...Mostly clear conditions will last through much of the evening with scattered high clouds overnight. Northwest winds will transition to southeast around 03Z. .REST OF UTAH AND SOUTHWEST WYOMING...Mostly clear conditions will transition to scattered high cloud cover with light winds through the overnight. Southwest winds gusting around 25 knots are likely throughout southern Utah by around 18Z. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...Flood Watch through Friday morning for UTZ107. WY...None. && $$ Seaman/Wilson For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity