Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/21/20

Area Forecast Discussion
National Weather Service Grand Forks ND
942 PM CDT Mon Apr 20 2020 .UPDATE... Issued at 942 PM CDT Mon Apr 20 2020 Clear sky has developed as high pressure builds into the region. Winds will continue to diminish and should be light and variable at some point after midnight. Watching the incoming guidance for Tuesday weather impacts. Not much change to the previous thoughts. Large temperature gradient across the region with a couple shortwaves quickly moving across the baroclinic zone should lead to to periods of snow/rain. At this point predictability is still low with details as the main forcing mechanism is Fgen and the upper waves in the northwest flow are not strong. Every solution is slightly different and will stick with the previous messaging. UPDATE Issued at 618 PM CDT Mon Apr 20 2020 Was able to allow the Red Flag Warning to expire at 6pm. Will be able to allow the wind advisory to expire at 7pm. One last area of scattered showers now across the central Red River Valley expected to continue to propagate south/southeast but diminish in the next hour or two. Still expect high pressure to build into the region this evening with sky clearing and winds diminishing. No impacts expected through tonight. && .SHORT TERM...(This evening through Tuesday night) Issued at 308 PM CDT Mon Apr 20 2020 Winds and shower activity will continue to be the main challenges for the period. Scattered showers continue across the forecast area, mainly from peak heating as the main shortwave has move southeastward into MN. Several of the model solutions from this morning show a lot of momentum transfer across most of our area this evening. So far the gusts have mostly been staying below 40 mph except for Valley City and Cooperstown at times, which is in the wind advisory. Some of the model soundings show the boundary layer mixing all the way to 700mb, which would bring 50 to 60 mph gusts. The RAP even shows the possibility of 65 or 70 in some places. Cold air advection is helping with some mixing, and there could be enough clear spots in the shower activity this afternoon to mix a bit more. Not sure we will get to 700mb, but at least 925 to 850mb where winds are around 35 kts. Will continue to keep the wind advisory going in our southwestern counties where there has been the most consistent high gusts, and will keep an eye on the other counties through this evening. Conditions will be much more quiet after sunset with weak surface high pressure building in and showers dissipating with the loss of heating. Temps should get pretty cold tonight with 20s and even some upper teens in NW MN where dew points are pretty low. Northwest flow aloft continues into tomorrow, and there will be a jet streak digging down that will put northwestern MN into the right entrance region of the feature. Frontogenesis is strong, especially at 850mb, as a warm front lifts into the CWA with 60s in southeastern ND and upper 30s/low 40s. Synoptic lift is not quite as strong, and although some models are indicating some banding potential, there is also the question of temperatures. Even with some cooling thanks to precip evaporating into dry air, think that any snow showers will mostly melt as they fall during the day on Tuesday. Maybe a dusting of snow as temperatures drop at night. A few of the CAMs try and break out a narrow band of higher QPF values and even some mixed precip is not out of the question. Given all the uncertainty will just continue to keep an eye on things as conditions develop tomorrow. .LONG TERM...(Wednesday through Monday) Issued at 308 PM CDT Mon Apr 20 2020 The chance for impactful weather is low within the long term period. Still expecting a warming trend to temperatures near normal, ie lows in the 30s and highs in the 50s to 60s. While the pattern is looking to become more active towards mid to late this week, significant precipitation is not forecast within the long term period. Wednesday starts cool with temperatures in the 20s and 30s with a small chance of very light precipitation, possibly a wintry mix for Minnesota locations. Warmer temperatures aloft should be in place by the start of Wednesday behind Tuesday`s system as the upper pattern remains northwesterly to zonal flow. This should allow highs to reach into the 50s and 60s, again cooler into northwest Minnesota. Upper pattern begins to shift Thursday and beyond with troughing favored over the Upper Midwest mid to late this week. This will bring period chances for light precipitation, especially on Thursday as a system is progged to develop out of the central or northern Plains into the Upper Midwest. Temperatures should remain warm enough that all rain is favored as the precip type. Still too early to comment on total QPF from this system as an uncertain track dictates this detail. With general troughing starting to build near the area, extensive cloudiness may moderate diurnal temperature swings with highs in the 50s and lows in the 30s generally expected. After this weekend, upper ridging or at least a breakdown of the troughing is forecast which would indicate warmer temperatures possible. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 618 PM CDT Mon Apr 20 2020 Scattered VFR cigs will dissipate quickly this evening leaving clear sky. Winds will also diminish and will be light and variable at some point tonight. Clear sky and light winds will continue until later Tuesday morning. Anticipate southerly winds along with VFR cigs at some point Tuesday afternoon. There is the low chance for a band of precipitation somewhere within the region, but at this time not sure where that will exist. && .HYDROLOGY... Issued at 942 PM CDT Mon Apr 20 2020 Pembina and Drayton remain at major flood stage. Pembina is expected to remain in major flood stage until the weekend. Drayton is expected to fall into moderate flood stage early Wednesday. Satellite continued to indicate a flood area generally east of I-29 from Manvel northward to Pembina ND. Road closures and overland flooding remain in and near this flooded area. Oslo continues at moderate flood stage and was the only forecast point at moderate flood stage. Fargo and East Grand Forks were at minor flood stage. East Grand Forks is expected to remain at minor flood stage until the weekend. Fargo is expected to fall below flood stage until early Thursday. Hallock, Abercrombie, Kindred, Harwood, Mapleton, and the West Fargo Diversion were at a high water stage. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. River point flood warnings continue across portions of the region. Refer to the latest flood warnings and statements for detailed information on specific locations. && $$ UPDATE...TG SHORT TERM...JR LONG TERM...CJ AVIATION...TG HYDROLOGY...JH
National Weather Service Hastings NE
826 PM CDT Mon Apr 20 2020 ...Fire Weather Update... .UPDATE... Issued at 825 PM CDT Mon Apr 20 2020 The bottom line: The Red Flag Warning was allowed to expire on time for our entire Nebraska coverage area (CWA) at 8 PM, as the last of the gusty winds from the afternoon hours are steadily diminishing and relative humidity (RH) values will continue a steady rise from currently 20s/30s to well into the 40s to around 50 percent over the next 1-2 hours. For more fire weather info (including a recap of today and a peek at "near-critical" potential tomorrow, please refer to the separate FIRE WEATHER section below... && .SHORT TERM...(This evening through Tuesday) Issued at 410 PM CDT Mon Apr 20 2020 Upper air analysis reveals NW flow across the central Plains due to troughing over E third of CONUS and ridging over W third. Visible sat has blossomed w/ diurnally driven cld cover over the past couple of hrs, aided by deep cyclonic flow on the backside of potent vort max S of Hudson Bay and deep mixing. The deep mixing allowed temps to quickly rise late AM along with momentum xfer of gusts 35-40mph. But w/ some areas now experiencing broken cld cover, temps have leveled off or even dropped a few deg. Fire weather issues in the very near term are discussed below. After sunset this eve, winds and lingering CU/Stratocu will quickly diminish as sfc ridge axis moves in from the NW. Mostly clr skies and relatively dry airmass should allow for cool low temps in the mid 30s to around 40. If winds really fall off, usual cold spots and low lying areas could fall to near freezing. Tuesday looks to be a much more pleasant day compared to today as temps will be warmer and winds much much lighter. The upper level flow will flatten some as the NE trough shifts E. After coordination w/ neighbors, decided to incr Tue highs above guidance, closer to extended RAP values. NBM and MOS blends have been consistently too cool as of late, and don`t see why Tue would be any different given copious amounts of sunshine expected. This gives highs in the mid 70s. As mentioned above, winds will be much lighter out of the south around 5-15mph, with maybe some gusts closer to 20mph for the aftn. All in all, a very nice day! May see some incr clds late in the day over the far SW, ahead of our next disturbance. There`s a slight chc some shwrs could sneak into Rooks and Philips Co by sunset, but overall, best chcs remain further S/SW until Tue night. .LONG TERM...(Tuesday night through Monday) Issued at 410 PM CDT Mon Apr 20 2020 A bit of a "messy" pattern in the extended w/ multiple pcpn chcs, but overall not very wet, and a mix of seasonably warm and cool temps. The upper pattern will continue the transition towards a flatter/more zonal look thru midweek. A progressive shortwave trough will shift E thru the Plains Tue night into Wed, but it looks like the brunt of this upper energy will slide by to our S. Wed night into Thu looks quiet, before another disturbance arrives in the zonal/NW flow later Thu in Fri, w/ perhaps another wave sometime around Sat. Then it appears upper ridging will build Sun into early next week. POPs have generally been reduced for the Tue night into Wed time frame as models suggest the core of upper energy remains largely across KS/OK. NAM remains the most aggressive w/ pcpn coverage/intensity along its N shield, but tend to favor ensemble/EC which keeps the N shield more muted. Have 20-30 POPs mainly along and S of the state line. Chcs appear a little better Wed aftn w/ some daytime heating along and ahead of a weak cold front. Modest CAPE values suggest some thunder potential, but shear values are weak. Highs look to range from upper 60s to mid 70s, coolest across KS zones where cld cover will be thickest. Thu looks to be another mild day ahead of next cold front and weak disturbance. This front may eventually spark off some shwrs or tstms Thu aftn/eve into the overnight, but it doesn`t look like anything too organized. Best chcs will be over the E half of CWA. Temps will cool off behind this system, with mainly 60s expected for Fri and Sat. Current 20-30 POPs for Fri may be overdone, as latest EC suggests mainly dry day. A shortwave in the NW flow could spark off some mainly diurnally driven shwrs on Sat, but again, nothing too heavy or organized. So again, extended is littered with several pcpn chances, but would not expect much QPF out of these given their origin and the upper pattern, and some places may miss these altogether. Ensembles are in good agreement for a warming trend Sun into early next week, with 80s a good possibility for at least portions of the CWA. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday) Issued at 654 PM CDT Mon Apr 20 2020 General overview: High confidence in VFR ceiling/visibility and rain-free weather through the period, with only limited mid-level "fair weather" stratocumulus mainly right away this evening, and then again perhaps Tuesday afternoon. That leaves winds as the primary issue, as gusty northwesterly speeds right away this evening will quickly die down overnight, before somewhat-breezy southerly speeds kick in for Tuesday afternoon. Read on for more wind-related details if interested... Wind details: The last of pronounced afternoon northwesterly gustiness will steadily subside this evening, but not before providing at least 1 more hour of gust potential to roughly 25KT. Already by 02Z, sustained speeds should be under 10KT, with a light/variable- direction regime then taking hold through much of the late- night/early morning hours as surface high pressure translates through. By mid-morning Tuesday southerly breezes will start to become established again, and most of the afternoon will feature a steady south-southwesterly wind frequently gusting 15-20KT. && .FIRE WEATHER... Issued at 825 PM CDT Mon Apr 20 2020 Follow-up on Monday`s Warning: There are very FEW "fire weather afternoons" during the spring/fall where conditions end up being "better"/less-severe than anticipated, but this was actually one of those rare cases where most of the Warned area struggled to consistently drop to 20 -percent-or-lower RH. Despite this "verification technicality", still feel the Warning was largely warranted from an impact-based standpoint given that RH values were "close enough", and especially given that northwest winds were every bit as strong (if not a bit stronger) than anticipated, as most areas notched peak gusts of 35-40+ MPH. We also had (unofficial) word of at least one grass fire that got out of hand for a time in our far western CWA. Looking ahead: Will defer to overnight shift to make the "final call" whether it`s worthy of introduction to our Hazardous Weather Outlook, but technically we are now forecasting parts of our Nebraska CWA to realize "near-critical" fire weather Tuesday afternoon (meaning overlap of RH 25 percent-or-less and wind gusts 20 MPH-or- higher). However, unlike today, south winds tomorrow should not be nearly as strong, precluding critical conditions and the need for a formal Warning. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...Pfannkuch SHORT TERM...Thies LONG TERM...Thies AVIATION...Pfannkuch FIRE WEATHER...Pfannkuch
Area Forecast Discussion
National Weather Service Wichita KS
1032 PM CDT Mon Apr 20 2020 .SHORT TERM...(This evening through Thursday) Issued at 331 PM CDT Mon Apr 20 2020 A weak cold front continues to push south across the forecast area this afternoon, with remnants from last nights convection over eastern KS dropping southeast into SW MO. Latest RAP does show some SBCAPE around 100 j/kg over extreme SE KS this afternoon, but the RAP also shows most of the moisture transport focusing the better moisture into SW MO. But as the front pushes SE, still could see a brief window for an isolated storm to develop over extreme SE KS for late this afternoon, as convergence increases and lapse rates steepen. Will keep a low pop in for a few hours late this afternoon, before any convective chances shift further E-Se into OK and SW MO. For the rest of the evening and overnight hours, expect mostly clear skies, as a weak area of high pressure rapidly drops southeast over the area. Expect seasonal temperatures for overnight lows. Weak ridging will remain in control for most of the daylight hours on Tue, as the ridge moves slowly east-southeast into the Ozarks. Attention then turns back to the west, as the next shortwave in the NW to zonal flow pulls out of the southern Rockies and into the plains for Tue afternoon. Latest models suggest that this shortwave will come into the plains in two pieces, with the initial impulse increasing lift and moisture transport for Tue afternoon for SW KS. Think scattered showers and some thunder will slowly shift east into south central KS by Tue evening, or possibly as late as overnight Tue. Not alot of instability as this initial impulse comes out, so think scattered showers and possibly an isolated storm or two will be the main concern. Second and stronger impulse looks to move out into the plains for early Wed, with a low pressure area developing over the OK panhandle. Some uncertainty on the track of this low, with the GFS taking it straight east across northern OK, while the ECMWF takes the low further south along the Red River. Both models seem to agree that the main mid level impulse and mid level frontogenesis associated with it, will move along the KS/OK border. This secondary shortwave has better moisture transport and increasing instability for early Wed morning. Think the rainfall amounts Wed morning will become more widespread than late Tue night. Bulk shear and elevated instability suggests possibly some strong to marginally severe storms for early Wed morning for areas south of highway 54, and certainly closer to the KS/OK border. Expect the heaviest rainfall amounts, around an inch, to be across southern KS and areas east of the KS Turnpike. Expect the showers and embedded storms to continue off and on across southern and SE KS for a good portion of the daytime hours on Wed, before gradually ending from west to east by Wed evening. Am a little concerned with the GFS showing the shortwave deepening over SW MO for Wed afternoon, which may lead to heavier rainfall amounts of 1.5 to 2 inches over extreme SE KS by Wed evening. This could lead to some localized flooding over SE KS if it materializes. Expect another lull in shower/storm chances for late Wed thru early Thu, as weak mid level ridging moves across the area. Good downslope flow will lead to max temps on Thu, climbing well above normal into the upper 70s, and possibly into the low 80s for portions of central KS. Ketcham .LONG TERM...(Thursday night through Monday) Issued at 331 PM CDT Mon Apr 20 2020 The dry conditions will be short lived, as another shortwave in the NW flow will drop SE across the forecast area for late Thu night as a cold front drops south. Could see scattered showers and thunderstorms for Thu evening into Thu night, with post frontal showers lasting into early Fri for much of southeast KS as well. Some uncertainty on how the weekend will play out, as NW flow will lead to a rapid succession of weak shortwaves dropping southeast. The next small chance looks to drop southeast for Sat. Ketcham && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) Issued at 1030 PM CDT Mon Apr 20 2020 VFR conditions will prevail across central and southern Kansas with light and variable winds switching to the southeast tomorrow. Showers and storms look to develop over northern Oklahoma and southwest Kansas which could push into central/south central Kansas by Tuesday evening. && .FIRE WEATHER... Issued at 331 PM CDT Mon Apr 20 2020 Widespread rainfall rainfall expected for Tuesday and Wednesday will lead to grassland fire values remaining low. Ketcham && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 49 75 52 64 / 0 0 50 70 Hutchinson 45 75 51 63 / 0 0 50 60 Newton 46 73 51 62 / 0 0 40 60 ElDorado 46 74 51 64 / 0 0 50 80 Winfield-KWLD 47 75 53 65 / 0 10 60 80 Russell 43 76 48 68 / 0 10 40 40 Great Bend 43 75 48 66 / 0 10 50 40 Salina 42 76 50 65 / 0 0 40 50 McPherson 43 74 50 62 / 0 0 40 60 Coffeyville 46 75 52 64 / 10 0 50 90 Chanute 45 73 51 62 / 10 0 40 80 Iola 44 73 50 62 / 10 0 30 70 Parsons-KPPF 47 74 52 63 / 10 0 40 80 && .ICT WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Ketcham LONG TERM...Ketcham AVIATION...CDJ FIRE WEATHER...Ketcham
Area Forecast Discussion
National Weather Service Lubbock TX
632 PM CDT Mon Apr 20 2020 .AVIATION... Showers across the northern half of the Texas Panhandle should stay north of the terminals. VFR conditions expected through much of the night with stratus expected to develop again late tonight toward dawn Tuesday. Models now focusing more on KLBB and KPVW for ceilings near high end IFR and low end MVFR with KCDS more questionable regarding extent of low cloud. Improvement expected early to mid afternoon Tuesday. && .PREV DISCUSSION... /issued 245 PM CDT Mon Apr 20 2020/ SHORT TERM... Afternoon RAP 500 mb analysis and water vapor imagery indicates an open wave pivoting into the Sierra Nevada Mountain range, along with a substantially weakened mid-level ridge oriented across the Rocky and Cascade Mountain region. At the surface, a weak, stalled front is draped across central New Mexico into central Texas. A surface low will begin to develop this evening across east-central New Mexico, with a pseudo-warm front that will drift north across the CWA overnight. As this happens, boundary-layer moisture will increase and a shallow stratus deck is forecast to develop during the mid-morning hours across the region in addition to localized patchy fog. Moisture return will continue throughout the morning and into the early afternoon hours, with a nose of strong theta-e advection orienting itself across the northeastern Rolling Plains Tuesday afternoon. Advected Layer Precipitable Water (ALPW) imagery indicates a modest EML across the Desert Southwest, and this EML will continue to advect east into the forecast area during the overnight hours. Strong ML theta-e advection, identified on ALPW imagery and modified 1200 UTC RAOBs from Flagstaff and Albuquerque, will result in the development of stout convective inhibition across the forecast area tomorrow afternoon. Beneath the EML, a moist boundary-layer will exist, characterized by a 60 deg F isodrosotherm and mean mixing ratios near 11-13 g/kg draped across the northeastern Rolling Plains. Backed surface winds will aid in localized surface convergence; however, surface-based parcels will likely fail to reach their LFCs due to strong CINH. The erosion of CINH should be rather slow during the early part of the day until the stratus deck mixes out. However, vertical thermodynamic profiles are supportive for the development of an isolated, high-based supercell or two across the central areas of the extreme southern Texas Panhandle and northeastern Rolling Plains Tuesday afternoon. This remains quite conditional despite the presence of an EML characterized by MUCAPE near 1,000-1,500 J/kg and favorable deep-layer shear. Should convective initiation occur, the orientation of the deep- layer shear profile (i.e. relatively straight, long hodographs) will favor strong precipitation ventilation in updrafts given anvil-level storm-relative winds in excess of 50 knots. LP supercells will be the primary storm mode with broad, mid-level mesocyclones supporting an attendant risk for hail production of 1-2" in diameter. Storms that do develop will have a residence time of several hours as they move along the southern Panhandle due to the increase in the low- level jet coincident with the arrival of the mid-level jet streak and associated wave. Chances for storms will begin to diminish after dark and upon passage of the cold front. Sincavage LONG TERM... Overall a quiet pattern is expected through the weekend. The axis of the upper trough will be across our western FA border by Wednesday morning and will push to our east by the afternoon. Some light showers and thunderstorms will be possible as the trough moves across the FA. A weak cold front will follow behind the upper low with highs getting into the low 70s to low 80s. Northwesterly flow will dominate going into late week. An embedded shortwave is progged to push across the central US Thursday evening/Friday morning bringing a slightly stronger cold front as the airmass source region is central Canada. This results in highs only in the 60s and 70s on Saturday. Winds are expected to quickly return to the south by Sunday. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 07
...Updated Aviation Forecast Discussion...

.DISCUSSION... Issued at 256 PM CDT Mon Apr 20 2020 Our Monday afternoon has been a breezy one, but still plenty warm despite the gusty northwest winds across the region. Temperatures are in the upper 60s to lower 70s with winds gusting 30-40 mph at most locations. Humidity fell into the 17-28 percent range as expected, with additional decreases likely in the next few hours, and the resulting very high to extreme fire danger will persist through approximately 7 PM today. One interesting feature at the moment is the southwesterly extension of a short wave trough as the trough axis is moving across the forecast area this afternoon. Ahead of the trough axis have seen an increase in shallow cumulus cloud cover at the top of the mixed layer near 10k feet AGL. There are a few weak returns showing up on radar, but with the high cloud bases and RH around 20 percent it is very unlikely that precip will reach the surface. Behind the trough, subsidence is evident in WV imagery over SD and now moving into far northern NE. This has helped to increase wind gusts a bit to 40 kts or stronger. Northeast NE may experience a few of these stronger gusts in the late afternoon hours as well, but should see a general decrease in the intensity as we approach sunset. Surface high pressure builds over the region tonight with winds becoming light by morning. This will offer an efficient radiational cooling night once the winds die down, and have adjusted temperatures a bit cooler than most guidance especially in northeast NE. Tuesday will feature a return of light southerly flow and warm advection. Model guidance has been persistently much too cool and moist with surface T/Td predictions in similar days this spring so have gone several degrees warmer and a good amount drier than almost all guidance...leaning close to a RAP solution. This will result in another day with RH potentially at or below 20 percent, but winds will be light enough that there is no extreme fire danger expected. Rather, it will probably be a "Top 10 day" with widespread upper 60s to mid 70s, sunshine, and light winds. Expect a bit of low-level moisture return on Wednesday in advance of a weak cold front. This could be sufficient to spark showers and a few thunderstorms along the advancing front in the afternoon. At this time, instability appears minimal and surface convergence along the front is not clearly strong enough to initiate convection so strong storms are unlikely. A better chance of rain arrives late Thursday into early Friday with a strong storm system and attendant cold front. Once again, instability is weak and while thunderstorms are possible it appears unlikely to pose any organized severe threat at this time. A few areas may pick up a half inch of rain or so. Will have some cold advection behind this system with Fri/Sat/Sun highs in the 60s. For the most part, morning lows should be around 40, but IF high pressure and clear skies should time themselves to arrive around sunrise on any given morning could see temperatures approach freezing. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 716 PM CDT Mon Apr 20 2020 No significant aviation impacts are expected through 00Z Tuesday. Conditions should be VFR, with light and variable winds tonight becoming light southerly winds between 15 and 20Z Tuesday. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Barjenbruch AVIATION...Albright
Area Forecast Discussion
National Weather Service Nashville TN
725 PM CDT Mon Apr 20 2020 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... A weak cold front is situated to our northwest early this evening and will swing across Middle Tennessee later tonight. In spite of relative dry air in place, the front should be able to gather up enough moisture to squeeze out a few light showers during fropa. The latest HRRR does show scattered light echoes from late this evening until early Tuesday morning, but all precipitation should be gone by 12Z. Then we`ll get back to mostly sunny skies tomorrow and pleasant temperatures. Hourly grids are in good shape for now. No forecast changes are planned this shift. && .AVIATION... 00Z TAF DISCUSSION. Conditions will stay VFR for the next 24 hours. A quick moving clipper system will move through the terminals overnight, but 00z OHX sounding shows ample dry air in the low levels. A couple light showers or sprinkles could impact the terminals, but cigs should stay VFR. Winds behind the system will shift to the NW and remain around 10 kts. Winds will become gusty by mid morning with gusts to around 20 kts for the remainder of the day. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......08 AVIATION........Reagan
Area Forecast Discussion
National Weather Service Pueblo CO
344 PM MDT Mon Apr 20 2020 .SHORT TERM...(This evening through Tuesday) Issued at 344 PM MDT Mon Apr 20 2020 ...More Active weather expected for Tuesday... Orphaned upper trof over the western U.S. will get picked up by Pacific jet energy and will translate eastward under the ridge and across CO on Tuesday. Ahead of this system this evening...high based showers and thunderstorms will be possible, particularly across the mountains and adjacent plains and southern border areas through this evening. CAPE is rather limited as low level moisture remains main threat with thunderstorms this afternoon and evening will be erratic gusty winds to around 40 mph or so. Thunderstorms should range from isolated to scattered in coverage at best. Activity winds down this evening, but with the approaching system will see shower chances increase again across the southwest mountains after midnight, spreading northeastward with time across southern portions of the southeast plains towards dawn. By morning should see fairly widespread rain and embedded thunderstorms spreading northward across the plains as moisture advection and overrunning sets up across the plains north of the front across NM/TX. Question will be how much instability there will be for strong to severe afternoon thunderstorms and how far north these ingredients will spread. Majority of the high res models keep stronger activity to the south, with 12z experimental HRRR the most optimistic model in bringing potential for marginal severe storms into Baca and Las Animas counties in the afternoon. 18z run seems to be shifting focus southward. To some extent moisture return tonight and amount of heating on Tuesday will be the primary driver of severe potential tomorrow. If all goes well, up to 1000 J/kg of CAPE could be lurking along the southern border with deep layer shears running around 40 kts or greater. This would lead to the potential for one or two strong to severe storms with hail the primary threat. However morning convection could also serve to stabilize things too much which would limit activity across southeast CO and place focus farther south. Either way, it appears there will be a good chance for some wetting rains across much of southern Colorado, and will carry high pops. Have leaned the forecast towards a more southward focus for severe potential, but this could change with later model runs. Higher elevations will also see a good chance of snow late tonight through Tuesday, with snow levels wavering between 9-10Kft. Snow accumulations of 2-5 inches will be possible across the higher elevations above 10000 feet. The higher peaks and passes along the Continental Divide will likely see slushy to snowpacked conditions at times under the heavier snow showers. Will have to watch the burn scars in the southeast mountains, particularly Spring and perhaps Junkins burn scar for heavy rainfall on the lower elevations of the burn scar. But for now think snow levels may be locally driven down lower and or small hail/graupel with any stronger embedded convective elements should help offset flash flood concerns. -KT .LONG TERM...(Tuesday night through Monday) Issued at 344 PM MDT Mon Apr 20 2020 Not many adjustments required from previous longer term meteorological reasoning as additional upper disturbances impact the CWA into late this week. Initially, scattered to numerous showers as well as isolated to scattered thunderstorms(some on the stronger to potentially severe side over the far southeastern Colorado Plains and also capable of producing locally heavy rainfall) ongoing late Tuesday afternoon/evening as an upper disturbance(per PV analysis) continues to impact primarily southern locations. Also, have depicted additional 12 hour snow amounts up to 3 inches over favored higher terrain locations from 6 PM MDT Tuesday to 6 AM MDT Wednesday. A brief lull in activity is expected over the CWA from Wednesday afternoon into Wednesday night in advance of next system producing generally isolated to scattered pops(including thunderstorms and higher terrain snow) from Thursday into at least Friday night. Then, drier and warmer conditions are still expected to develop over southern Colorado(especially from later in the weekend into early next week) as upper ridging builds into southern Colorado. Minimal fire weather concerns are expected continue over the majority of the CWA into the weekend, with increasing fire potential developing by early next week. In addition, it still appears that the highest potential for more widespread gusty winds over the CWA during the longer term should be realized over primarily eastern locations from Tuesday night into Wednesday and then again from Thursday evening into Friday night. Finally, coolest temperatures during the longer should still be noted Friday, with warmest temperatures expected Sunday and especially Monday(with maximum temperatures on Monday expected to climb into the 80s over many eastern locations). && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 344 PM MDT Mon Apr 20 2020 VFR conditions expected at the TAF sites with high based showers and isolated thunderstorms this evening. Main threat will be gusty erratic winds up to 30 kts near high based showers this evening along with brief VFR CIGS. CIGS will lower overnight but predominantly remain VFR at all three TAF sites (KCOS, KPUB and KALS). A wave of showers will lift northward bringing the chance for some -SHRA at KALS early Tues morning, spreading northward into KPUB and KCOS by mid day. Some local MVFR cigs will be possible under the heavier showers and isolated embedded thunderstorms during the afternoon. Mountain areas will see mtn obscurations spread in late tonight along the Continental Divide spreading eastward into the southeast mountains on Tuesday. Expect IFR to LIFR conditions over the mountains above 10000 feet with periods of SHSN. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
Area Forecast Discussion
National Weather Service Las Vegas NV
845 PM PDT Mon Apr 20 2020 .SYNOPSIS...An area of low pressure will slowly move across the area and bring another round of showers and isolated thunderstorms to parts of the region. Impacts are expected to be low but a few lightning strikes and gusty outflow winds are possible where storms develop, mostly off higher terrain. Dry and much warmer weather is on the way for the latter half of the week and lasting into the weekend. Expect plenty of sunshine to go along with the warmer weather and occasional breezy winds. && .UPDATE...The area of showers and thunderstorms that brought record rainfall to Las Vegas this afternoon continues to shift northeast this evening and are currently moving out of Clark County and into northern Mohave County. With loss of afternoon heating these showers and storms have been gradually weakening with just a couple of lightning strikes over the past hour. Rainfall rates have also decreased significantly with just a few hundredths reported. There have been a few pop up isolated showers across southern Inyo and eastern San Bernardino Counties this evening, but overall these will remain weak and produce additional light rain amounts. Forecast in good shape and no updates planned. && .AVIATION...For McCarran...Outside of a light shower overnight, conditions are not expected to be impactful overnight. Light diurnal winds and mid-level clouds are expected. Winds will likely turn northward Tuesday morning with a frontal passage. North winds may approach 10-12 knots at times. Shower activity is not expected in the valley, but cannot rule out outflow winds from showers that develop over the terrain. For the rest of southern Nevada, northwest Arizona and southeast California...Shower activity will be widely scattered overnight across the Mojave Desert and southern Great Basin. Most sites should remain dry; however, light showers cannot be ruled out in the Owens or Las Vegas valleys. With showers, temporary lower ceilings are possible otherwise ceilings will stay between 8-12 kft. Winds are expected to be light and favor diurnal trends up until a frontal passage tomorrow (Tuesday) which will redirect winds northerly. && PREV DISCUSSION 231 PM PDT Mon Apr 20 2020 .SHORT TERM...through Tuesday. Latest HREF and HRRR trends continue to show showers and isolated thunderstorms developing after this afternoon out west off the higher terrain of Inyo County and around 00Z farther east as the weak low moves over the region. While this low will produce a similar low end PoP/Thunder chance for this evening to what we`ve seen over the last several days, this activity will be largely driven by instability and lack dynamic support. Thus feel fairly confident that initiation will be largely tied to higher terrain areas such as the Springs, Sheep Range, and possibly Black Mountain. That being said, RAP instability shows some impressive CAPE values and with the cooling 500 mb temps and increasing surface moisture this evening, can`t argue with the trend upward. So included thunder over a larger area than previous forecasts, now encompassing much of Clark County. DCAPE values look meager compared to previous days but can`t rule out some gusty outflow winds up to 30 mph with thunderstorms either. The low is progged to center itself over southern Nevada by early tomorrow morning and shift east moving into the afternoon so PoP potential lingers through the overnight period but looks looks less likely after 12Z Tuesday and should be more confined to .LONG TERM...Wednesday through the Weekend. A much more benign weather pattern is in store through the rest of the period. The biggest news for the long term period is the prospect for the first 90+ degree day for the LV Valley and 100+ day for Death Valley which looks like it will be Thursday before a brief cool down Friday and Saturday and return to 90+ highs by Sunday according to the latest NBM. The first broad, significant amplitude ridge looks to build over the eastern Pacific as our current low pushes east and will shift to the west coast by the late week. This should serve to finally push the overall flow well to the north and keep any new shortwaves across the northern US or Canada. Looking all the way through 240hrs, there is good agreement in the 12Z deterministic long range models and diving into ensemble analysis, this only question seems to be how deep will it get and thus how much warmer will get in the 8-10 day time frame. NBM seems to be fully on board with such agreement so no changes were made at this time to the long term. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ DISCUSSION...TB3 AVIATION...Kryston For more forecast information...see us on our webpage: or follow us on Facebook and Twitter