Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/14/20

Area Forecast Discussion
National Weather Service Caribou ME
931 PM EDT Fri Mar 13 2020 .SYNOPSIS... Low pressure will move east of the forecast area tonight. High pressure will build toward the region later Saturday through Sunday, then move east on Monday. A frontal system is expected to move into the region on Tuesday. High pressure returns Wednesday. && .NEAR TERM /THROUGH SATURDAY/... 915 PM Update...The the Winter Weather Advisory was allowed to expire. The St. John Valley came out the winner w/this latest storm. The St. Agatha and Madawaska are received 10 and 12 inches of snow respectively. Less amounts as one travels east and to the south. The NWS Office in Caribou measured 4.2 inches of snow. Snow has come to an end as seen on the latest radar loop. Some fog has developed this evening as winds have dropped off significantly and llvl moisture remains. The thickest fog is across the St. John Valley. The fog is expected to lift over the next few hrs as winds start to pick up. Adjustments were made to the hrly temps and snowfall amounts. Slight adjustment to the winds to start them out lighter than previously expected. The 18Z NAM and latest RAP had things handled well. Previous Discussion... The pressure gradient will remain very strong tomorrow between the roughly 990 mb trough off to the north and a 1032 mb ridge over the Ohio River Valley. Clearing and advection of cold air aloft will lead to efficient mixing of winds to the surface during the day Saturday, with gusts very close to wind advisory criteria based on forecast soundings. Self-destruct stratocumulus will develop and could slightly hinder fullest mixing potential. Higher elevation sites could see gusts up to around 50 mph, but most locations should peak around 45 mph. Isolated snow showers are possible over higher terrain favored by the upslope flow. Winds will diminish gradually during the evening as a weak surface inversion begins to form. Blowing snow will be possible across the far north where heavier precipitation ends as snow, but coverage and intensity may be limited by current above freezing temperatures. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... Cyclonic flow conts Sat night into Sun as low departs into the Maritimes. In it`s wake stratocu wl continue ovr the north and west. Cannot rule out a flurry or two over favored areas but does not appear likely given dry airmass moving in. Sfc high pressure wl be building twd the area out of Canada on Sun night and with winds decoupling and skies clearing hv undercut guidance by about 3-5 degrees for the deeper vlys in the North Woods. High builds offshore drg the day on Monday leaving sunny skies along with light swrly winds in the aftn. After a cold start to the day expect that highs wl rise to blo normal values with m/u20s expected over the north and l/m30s for Downeast areas. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... High pressure builds off the coast and return flow wl spread pcpn into the area on Tue, likely starting as snow across the north and a rain/snow mix over central areas as well as rain along the coast. Cold front quickly moves thru Tue night with temps on Wed dropping down to near normal after an above normal day on Tue. A return to high pressure will keep systems at bay on Thursday before an active wx pattern returns next Friday. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: IFR conditions will improve to VFR overnight. Low level wind shear will be possible overnight as winds aloft shift W and strengthen while surface winds decrease. Brief periods of MVFR are possible across the north in isolated -SHSN. SHORT TERM: Sat night-Mon night...VFR at all terminals. KFVE may see MVFR cigs Sat night before improving. NW winds 10-20kts Sat night/Sun with gusts to 20kts. Light winds Mon morning becoming SW around 5kts. Tue-Tue night...IFR due to cigs and rain/snow moving in Tue morning increasing to MVFR/VFR Tue night at Downeast terminals. S 10-20kts and gusty on Tue becoming W late Tue night. Wed...Becoming VFR across the north. W 5-15kts. && .MARINE... NEAR TERM: Gales continue across most of the waters tonight through the forecast period with a very brief break of a couple hours as winds shift from south to west and increase again by midnight. Competing swells will create choppy seas overnight and into tomorrow along with maintaining wave heights over 6 feet. Lengthy SCA conditions are expected over the intracoastal waters after midnight tonight, when gales expire over these waters only. SHORT TERM: Gales drop off to strong SCA conditions Sat evening and below SCA Sun morning. Seas also diminish to blo 5ft Sun morning and remain below until increasing in southerly swell on Tuesday before dropping again Wed. Gales will be possible again on Tue. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Gale Warning until midnight EDT tonight for ANZ052. Gale Warning until 8 PM EDT Saturday for ANZ050-051. && $$ Near Term...Hewitt
Area Forecast Discussion
National Weather Service Cheyenne WY
948 PM MDT Fri Mar 13 2020 .UPDATE... Issued at 939 PM MDT Fri Mar 13 2020 We are sending out another update to expand the Freezing Fog Advisory further east to Pine Bluffs overnight. Latest water vapor loop was showing the potential vorticity anomaly continuing to shift eastward with quite a bit of potential vorticity advection taking place in the central Nebraska panhandle. In fact, Scottsbluff has dropped to 1/4 mile in snow/blowing snow during the last hour or so. As a result, they could pick up a total of 3 to 4 inches of snow before ending. The Pine Ridge could even pickup a little more. Thus, the Winter Storm Warning still looks valid for that area. Meanwhile, the dense fog will persist especially along the Cheyenne Ridge where southerly flow will persist through at least daybreak and perhaps through mid morning Saturday. Overnight shift may need to expand the Dense Freezing Fog Advisory further east into the Nebraska panhandle, due to moist upslope flow. UPDATE Issued at 825 PM MDT Fri Mar 13 2020 We are sending out a quick update to introduce freezing drizzle in portions of the southern Nebraska panhandle. Latest observations from Sidney was reporting freezing rain/drizzle across that area during the past couple of hours. In fact, webcams are showing some icing taking place on them. Latest water vapor loop/IR imagery was showing a dry slot over that region, but it appears to be filling in during the last 30 minutes. Regardless, it will most likely create slick conditions in this region through midnight. Meanwhile, IR imagery was showing some heavier bands of snow developing along and north of a Bayard to Alliance line. We just had a spotter call in just north of Bayard and reported low visibility and blowing snow in this region. The latest Hi-Res models are showing this band of snow exiting the panhandle by around midnight. UPDATE Issued at 340 PM MDT Fri Mar 13 2020 Southeast upslope winds continuing this afternoon. Does not look like they shift through the overnight hours. Latest CYS ASOS reporting 1/4 mile in FZFG. Went ahead with a Freezing Fog Advisory for central Laramie well as the eastern foothills as well as the Summit through 12Z Saturday. Updates have been sent. && .SHORT TERM...(This evening through Saturday) Issued at 220 PM MDT Fri Mar 13 2020 Forecast concerns deal with snow accumulations today through Saturday morning. Currently...Surface low pressure system over eastern Utah and western Colorado this afternoon. Arctic boundary lays across South Dakota into southern Montana. Southeasterly upsloping winds east of the Laramie Range with over running mid level moisture from the southwest low moving into the I-80 Corridor from the southern Panhandle over to Evanston. Getting some banded snow being seen on radar over Cheyenne at this time...but it is shifting north. Latest HRRR and Hires guidance showing a band developing over the northern Nebraska Panhandle late this afternoon...persisting through at least midnight before shifting north of the CWA. GFS...NAM and ECMWF all in good agreement with close to 1/2 inch QPF over the northern Panhandle late this afternoon through 06Z. NAM most bullish still at 3/4 inch. In an earlier update...upgraded advisories to warnings for the northern half of the Nebraska Panhandle. Snow looks to taper off significantly after 12Z Saturday and we may need to cancel the winter headlines earlier than what we have in now. Later shifts can handle those issues. .LONG TERM...(Saturday night through Friday) Issued at 220 PM MDT Fri Mar 13 2020 By the end of the weekend, a broad upper level ridge will be centered over the Central US as an upper level low positions itself off the Pacific NW Coast. The progression of this trough will shape the weather for the upcoming week. For Sunday and Monday, dry weather temporarily returns to the region as areas south of the North Platte River Valley could see temperatures warm up into the mid-50s by Monday afternoon. A cold front will push through during the day Monday resulting in areas to the north remaining colder in the low-40s and upper 30s. This front may trigger a few snow showers early Tuesday morning along the Cheyenne Ridge, however these should remain light. A weak shortwave looks to eject out from the Pacific low Tuesday which could bring another chance for light precipitation Tuesday evening across the southern NE Panhandle and farther east into central Nebraska. Looking ahead, the Pacific low will begin to propagate eastward resulting in a active weather pattern mid- to late-week. Currently, both the GFS and Euro slowly propagate the closed low down the Pacific Coast before interacting with the sub-tropical jet. As the upper low moves inland, models begin to depict strong lee cyclogenesis over eastern Colorado starting Thursday morning. The GFS deepens the sfc low to 994 mb while the Euro is slower and stronger with a 990 mb sfc low slightly farther north. Both solutions have a rather large precipitation field on the NW side of the sfc low over much of eastern Wyoming and Nebraska and strong northerly sfc winds in a rather tight pressure gradient near the NE/CO border. With differences in positioning and timing of the 500 mb low, upcoming shifts will need to keep a close eye in the coming days. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 529 PM MDT Fri Mar 13 2020 Snow showers should become more scattered Rawlins east to Sidney through the evening hours, even though periods of low ceilings and freezing fog could be an issue for those areas, especially 02z-06z before the winds become more southwesterly and downslope. Farther east, periods of snow with visibilities and ceilings down to IFR/LIFR through late evening before starting to taper off toward morning. Low ceilings will likely hold across most western Nebraska Panhandle sites tonight given favorable low level winds, with the exception of Chadron which could see a downslope component late tonight. && .FIRE WEATHER... Issued at 300 PM MDT Fri Mar 13 2020 Minimal fire weather concerns over the next several days. Areas of southeast Wyoming likely to see accumulating snow...especially for the mountains and areas east of the Laramie Range into the Nebraska Panhandle. A low pressure system near the Four Corners area this afternoon will continue to track towards the northeast bringing this widespread snow. Snow ends Saturday morning...but new snowpack will be in place to keep fuels wet. Dry Sunday and Monday as high pressure moves over the area. Next chance for snow looks to be Thursday into Friday next week as a strong low pressure system tracks across northeast Colorado. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Winter Weather Advisory until noon MDT Saturday for WYZ102-108- 112. Freezing Fog Advisory until 6 AM MDT Saturday for WYZ116>118. NE...Winter Storm Warning until noon MDT Saturday for NEZ002-003-021- 095-096. Winter Weather Advisory until noon MDT Saturday for NEZ019-020- 054-055. && $$ UPDATE...REC SHORT TERM...GCC LONG TERM...MB AVIATION...JG FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Des Moines IA
632 PM CDT Fri Mar 13 2020 ...Updated for 00z Aviation... .DISCUSSION.../Tonight through Friday/ Issued at 312 PM CDT Fri Mar 13 2020 Tonight into Saturday...main forecast concern was focused on the light snow potential across the central and southern sections of the forecast area. The latest HRRR/RAP/NAM in decent agreement with timing of the snow starting and location of the high amounts. A slight change to the western portions of the forecast area with higher QPF and thus higher snow amounts. Confident the precip type will be either rain/snow with complete saturation in the dendritic layer. Decent frontogenetical band of forcing sets up from around Denison south-southeast through Des Moines down to Lamoni and this area has a better chance to see the 2-3 inches (isolated 4") of snow by late Saturday morning. This frontogenetical band should be strong enough to overcome the deep dry layer near the surface, but lower confidence with any snow amounts further north, especially northward toward Highway 20 as the forcing remains weak that far north and shouldn`t be enough to overcome the surface dry layer. There looks to be a sharp gradient of snow amounts and generally along and south of Interstate 80. The latest RAP and GFS via Bufkit soundings are a bit concerning with the slightly higher snow amounts in the Des Moines area but did trend up the totals. However, roads temperatures this afternoon range from 60-70F over central to southern Iowa, so there will be plenty of melting before the snow begins to accumulated. Obviously higher totals are likely on grassy and elevated surfaces. The other caveat are the winds as they will increase out of the east Saturday morning and look to be enough to cause some visibility concerns, especially in the aforementioned frontogenetical heavier band. The forcing and moisture quickly move east of the forecast area past 18z Saturday and thus pops rapidly drop off. Enough snow and wind to hoist a wintery weather advisory over the west and south and there is the potential it may need to be extended further northeast to include the Des Moines metro if the snow amounts come in a bit higher. Sunday into Wednesday...large surface high pressure dominates the weather pattern providing a cool and dry period for much of the state. Still looking at a cold front through Monday night, but the bulk of the moisture remains north and kept the forecast dry for now. Thursday and Friday...ECMWF and GFS have come into decent agreement with the timing and location of a fairly strong surface low to eject out of the OK/TX Panhandles. The ECMWF is a bit slower and a shade further south, but overall for 156-180 hour forecast, surprisingly in good agreement. The majority of the forecast are remains the warm sector and provides thunderstorm chances, but there looks be a snow band to set up across the north to northwest portions of Iowa Thursday night into Friday. && .AVIATION.../For the 00Z TAFS through 00Z Saturday evening/ Issued at 632 PM CDT Fri Mar 13 2020 VFR conditions this evening will give way to deteriorating conditions overnight through the day Saturday, primarily at southern sites as snow moves across the state. KOTM/KDSM will see IFR visibility towards sunrise as the heaviest snow arrives, with MVFR cigs. Included a -SN mention at KFOD, however for now have kept at VFR conditions as this will be the far northern extent of the precip. && .DMX WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 1 AM to 3 PM CDT Saturday for IAZ044-045-057-058-070>072-081>084-092>097. && $$ DISCUSSION...Podrazik AVIATION...Hagenhoff
National Weather Service Hastings NE
1055 PM CDT Fri Mar 13 2020 .UPDATE... Issued at 1050 PM CDT Fri Mar 13 2020 Have made some minor adjustments to POP and WX grids based on radar, satellite and model trends. Thoughts below: 1) Have added some drzl/frz drzl. Areas without significant radar returns are probably seeing this due to lack of saturation in DGZ. These areas are transient and given marginal sfc temps near freezing, doubt there will be much impacts. Perhaps some lt glaze on elevated surfaces. 2) We`ve been in a lull late this eve, but models show uptick in QPF in the 06Z- 12Z time frame. Thus, have not made any significant changes to snow amounts. There`s still factors of warm ground and wet snow/low ratios fighting against higher amounts. Still think most areas in advisory will see 3-5", with some isolated areas near 6" still possible. However, so far, impacts to roads has been fairly minimal. 3) Didn`t make any headline changes on this shift, but may very well need to move up the end time as most, if not all, appreciable QPF should be done by ~15Z. Caveat to this could be lingering potential for fzdz. However, even by 18Z will likely see temps rise 1-2 deg, which combined with March sun angle, would be enough to eliminate icing threat. Will let midshift coordinate with neighbors on this potential update. && .SHORT TERM...(This evening through Saturday) Issued at 342 PM CDT Fri Mar 13 2020 Aloft: As has been the case since mid-Nov...mainly zonal flow remains over the CONUS. Aircraft wind obs and RAP dynamic tropopause analyses indicated anticyclonic WSW flow over NEB/KS. A shrtwv trof extended from the UT-CO border down into AZ. This trof will lift NE and cross the CWA late tonight into tomorrow AM. Heights will rapidly rise in its wake...with a broad ridge forming over the Plns in response to the next low diving S along the W coast. Surface: 1050 mb high pres over Wrn Canada extended SE into the Cntrl USA. The cool front that moved thru here Thu AM was over Cntrl TX and the Gulf Coast states. Weak low pres will form along that front tonight into tomorrow...while high pres conts to dominate acrs Srn Canada. That will keep E winds over the CWA thru tomorrow. Rest of this afternoon: Radar mosaic shows predominantly -SN overtaking the CWA. The leading edge is not reaching the ground due to low-lvl dry air. Where temps have climbed into the low 40s...the leading edge of pcpn reaching the ground was falling as -RA. Expect RA/SN to cont advancing NE. NDOT traffic cams indicated snow accumulating on grassy areas along Hwy 136 W of Riverton. Snow is probably accumulating over Gosper/Phelps counties as well. With temps above frzg and concrete/pavement still absorbing insolation...the snow was melting on contact. So roads were just wet attm. Tonight: Snow will overtake the entire CWA. Once the sun goes down and roads and temps cool...snow will begin accumulating on roads. Temps will fall to near 32F and hold steady. The latest blend of mdl QPFs came in a touch higher than prvs fcsts. Snow ratios were capped at 10:1 given near-frzg temp profile. That still resulted in some 6" amts over parts of Dawson/Gosper/Phelps/Furnas counties. Winter Wx Advy conts as posted at 4 AM...but the possibility of 6" amts necessitated upgrading Dawson/Gosper/Phelps/Furnas to a wrng. Given that this is a weak system...and no strengthening expected...and initial melting and compaction due to warm ground...most locations should remain at or below 5". Expect a gradient of 1-5" from SE-NW acrs the CWA with isolated 6" psbl in the warning area. Sat: Snow will taper off and end during the morning from SW-NE. There`s a chance a little snow could linger into early afternoon N and E of I-80...but the accumulating snow will be over. Highs in the 30s. Wind will not be a big issue with this system as there is no sfc low anywhere nearby. E 10-20 mph with some gusts around 25 mph at times. The wet character of the snow will minimize blowing and drifting. After the snow ends...remaining cldy. There is a chance that some patchy drzl could occur. .LONG TERM...(Saturday night through Friday) Issued at 342 PM CDT Fri Mar 13 2020 Aloft: Low-amplitude anticyclonic W-WSW flow will cont over NEB/KS thru a strong low sinks down the W coast...a low remains over Hudson Bay...and a subtropical high remains parked over the Caribbean. The W coast low is fcst to creep slowly inland Wed and this will back winds to SW over the CWA. Some acceleration is psbl Thu as another low dives into the backside of the longwave trof. The last 2-3 runs of the EC/GFS-FV3/CMC are now consistent on lee cyclogenesis Thu night with a new low forming and briefly intensifying over NEB. It is then fcst to weaken on its way into the upr Midwest Fri. Surface: The strong high over Srn Canada will head E Sun. A very wk cool front will form over the Nrn Plns Sun night and it will cross the CWA Mon eve. Behind this front...another big Canadian high will gradually slide ESE into New Eng by Wed. In the meantime...the cool front will become stationary over the Srn Plns. Lee cyclogenesis will begin over CO Wed. This will force the front to lift back N as a warm front. The CO low will intensify Thu. This is still a week there are timing/location diffs between the mdls...but that low is fcst to eject out acrs NEB/KS Thu night into Fri. The warm front will probably lift as far N as the state line. Meanwhile...a Canadian cold front will drop S Thu night and merge with this system...increasing the temp grad. Temps will average at or below normal thru next Fri. The chilliest day will be Sun. Don`t expect much increase in temps before Thu as this entire fcst is looking very cldy. We could see a temporary pop in temps Thu as the warm front gets close...but the cool front will quickly follow Fri. Precip: As with yesterday...NBM has a lot of pops/precip chances that I really don`t think are warranted for large portions of time between Sat night thru Mon night. Am not saying it will be completely dry...but whatever falls will be very light and minor. Changed the character of the precip to drzl as clds will be very shallow and all liquid/no ice. The next legit rain chances will arrive Tue night into Wed and then Thu-Fri. Rumbles of thunder still possible...espcly Thu night. This Thu-Fri system could be a soaker for S-cntrl NEB...espcly W and N of the Tri-Cities. Hvy wet snow will be psbl NW fringe of the CWA. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday) Issued at 653 PM CDT Fri Mar 13 2020 Significant wx: Prolonged period of IFR conditions. Tonight: High confidence for IFR CIGs and VSBYs. Minimum CIGs and VSBYs could drop to LIFR at times during heaviest bands. E winds will gradually incr this eve, with gusts 20-25kt overnight. Expect 2-5 inches of snow accumulations during this time. Saturday: High confidence IFR CIGs through much, if not all of daytime hrs Sat. IFR VSBYs will most likely be ongoing at start of the period in continued -SN. Additional inch or so of accumulation expected 12-18Z. Eventually, expect VSBYs to improve to MVFR levels by mid to late morning as snow decr, but lingering boundary layer moisture and upslope component to winds may allow light fog to continue thru daytime. Expect continued IFR CIGs and return to IFR VSBYs Sat night. && .GID WATCHES/WARNINGS/ADVISORIES... NE...Winter Weather Advisory until 4 PM CDT Saturday for NEZ039>041- 046>049-061>064-074>077-083>086. Winter Storm Warning until 4 PM CDT Saturday for NEZ060-072-073- 082. KS...Winter Weather Advisory until 4 PM CDT Saturday for KSZ005-006. && $$ UPDATE...Thies SHORT TERM...Kelley LONG TERM...Kelley AVIATION...Thies
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
948 PM CDT Fri Mar 13 2020 .UPDATE... Updated for evening discussion. && .DISCUSSION... Only a few light showers over the far north indicated on radar, but not going to rule out a few more overnight overtop the stalled boundary over south MS. Of greater concern will be the fog potential over the southeast after midnight. HRRR has been persistent with areas of dense fog moving into these areas, but at present, closest fog showing up in buoy data well offshore./GG/ Prior discussion below: Tonight and Tomorrow: The front is now lingering along the I-20 corridor this afternoon with all of the precip developing to the north of the boundary. Precip continues to be light and showery throughout those areas. To the south of the boundary, clouds are breaking up and temperatures have risen nicely into the upper 70s and lower 80s. Going into tonight, the showers are expected to diminish as the limited instability decreases even more. Patchy fog will develop along the Gulf Coast overnight and spread northward into our Pine Belt region. The boundary will begin a shift northward early Saturday morning and winds will shift out of the south again. As for Saturday, with the warm front lifting ever farther north into eastern OK to the Mid- Mississippi Valley, only limited rain chances are expected within our CWA. The counties/parishes in our northwest CWA and closest to the boundary may see some showery activity in the morning. With warm air advection picking back up throughout the area, temperatures areawide will warm into the upper 70s to lower 80s. /10/ Saturday night through next week... Chances for showers and isolated thunderstorms remain in the forecast through most of the period. With ridging over the region, the best chances for this activity will remain across the northern part of the forecast area. Ridging will dampen some Saturday night into Sunday as another front drops into the region. This will allow for quasi-zonal flow to be in place, with disturbances passing through every day or couple of days. Again, the best chances for rain will be in the north. During this period, temperatures will be very springlike, especially across the southern sections of the ArkLaMiss, which may not see as much rain. Across northern parts, thanks to clouds and rain, highs will be in the 60s and may reach 70. However, highs will easily reach the 70s and even some lower 80s in the south through the week. Overall, it looks to be a rather wet period through much of the week with multiple disturbances moving through. /28/ && .AVIATION... 00Z TAF discussion: A cold front, south of a TVR-JAN-MEI line, will become stationary this evening and begin moving back to the north Saturday morning. To the north of the front, MVFR ceilings and isolated showers will continue through much of the period as winds stay from the northeast at around 10 knots. To the south of the front, southerly winds around 5 knots early will diminish by mid evening. Thereafter, IFR and LIFR conditions will develop from the south as areas of fog move inland from the Gulf of Mexico. These conditions will continue until mid morning then slowly improve through the afternoon./GG/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 63 80 61 74 / 15 13 24 21 Meridian 61 81 61 77 / 17 7 17 24 Vicksburg 64 80 61 70 / 18 20 27 25 Hattiesburg 61 82 59 83 / 10 5 3 7 Natchez 64 80 62 76 / 10 12 13 17 Greenville 53 75 53 58 / 23 32 79 44 Greenwood 57 77 56 62 / 23 27 73 46 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$
Area Forecast Discussion
National Weather Service Midland/Odessa TX
649 PM CDT Fri Mar 13 2020 .DISCUSSION... Please see 00Z aviation discussion below. && .AVIATION... Sfc winds have increased around 12-15 kts this evening out of the ESE ahead of a strong upper-level system. Isold -TSRA have developed INVOF CNM and PEQ and will continue to migrate ENE through tonight affecting all terminals through 06Z. Currently IFR VIS w/FG has set in behind a cold front at MAF and HOB and gradually improvent is likely tonight as -TSRA move through remaining TAF sites. Some storms could produce hail and gusty erratic winds. CIGS/VSBY should improve to VFR at most terminals between 04-06Z. && .PREV DISCUSSION... /issued 126 PM CDT Fri Mar 13 2020/ DISCUSSION... Kinematic and thermodynamic parameters are setting up for a round severe wx starting late this afternoon as a 130kt 3h jet moves across the area into the overnight. Deep convective initiation will likely be delayed due to limited insolation and thus importance of jet. Initiation on high resolution models is probably a few hrs early, but is expected to occur in the far wrn CWFA. Storms and attendant threats will largely be determined by a cold front that will be located INVOF Pecos River and its potential to move n as a warm front into the overnight. Of course there is some uncertainty WRT the frontal position and therefore temps and CAPES this PM. For now we are most concerned about the discrete supercells in and around Reeves, Winkler, Ward, Pecos, Crane, Midland, Ector, Upton, Reagan, and srn Lea Counties. Concerns could be farther s and w depending on the front and when it starts to move back to the n. Derived severe wx indices/parameters and soundings are indicative of tornadic potential and splitting supercells. 12Z-15Z HRRR simulated radar suggestive of multiple discrete cells with long- lived strong updraft helicity tracks across wrn/srn PB and Pecos County. We have collaborated with SPC/SJT and risk has been increased to enhanced earlier today. Tornadoes are possible today (see SPC TOR probabilities), even a strong tornado cannot be ruled out and the most favored area for a tornado will generally be bound between I-20 and I-10. Storms that move farther n in wake of the front will be elevated, but nonetheless still maintain severe potential, parcels lifted from 85h still result in CAPES around 1000 J/KG. We are also concerned that instability could be maximized in the Lower Trans Pecos and the Big Bend area, there are lots of vacationers down at BBNP and we have increased PoPs there. Sat temps will increase and conditions will dry in wake of the exiting system. The cold front will surge back s late Sat night-Sun AM setting up SUN PM to possibly be much cooler (NAM12 has highs in the 40s for much of the PB!). Another mid-level speed max in the sw flow aloft will attempt to generate some light precip in combo with low-level waa aloft the front. A mid-level speed max will come out of MX Sun night with a cluster of storms moving across Trans Pecos, somewhere from the Davis Mtns-Terrell Co. Cold air may be slow to erode out the PB Mon? Active and probably wet sw flow still advertised Tue-Thur. && .PRELIMINARY POINT TEMPS/POPS... Big Spring 53 74 50 60 / 80 0 20 80 Carlsbad 47 74 48 67 / 10 0 10 50 Dryden 62 82 61 77 / 30 0 10 40 Fort Stockton 54 77 58 74 / 30 0 20 60 Guadalupe Pass 43 63 47 64 / 10 0 0 30 Hobbs 46 72 47 60 / 50 0 10 70 Marfa 46 76 48 77 / 10 0 0 20 Midland Intl Airport 53 76 53 63 / 70 0 20 80 Odessa 53 76 53 64 / 70 0 20 80 Wink 51 77 53 68 / 40 0 10 70 && .MAF WATCHES/WARNINGS/ADVISORIES... NM...None. TX...None. && $$ 24
Area Forecast Discussion
National Weather Service Pueblo CO
542 PM MDT Fri Mar 13 2020 .UPDATE... Issued at 539 PM MDT Fri Mar 13 2020 Based on current observations (CDOT Cams) and a variety of guidance, have issued a dense fog advisory for El Paso County into tomorrow morning. Conceptually, with upslope flow continuing through tonight, moist airmass already in place and trough still to our west, dense fog will be possible and it will likely be widespread. We may also need a dense fog advisory for the far eastern plains later this evening. && .SHORT TERM...(This evening through Saturday) Issued at 333 PM MDT Fri Mar 13 2020 Upper low shearing eastward and weakening across Colorado this afternoon, with main warm advection band and associated precip shifting eastward into KS. Still a good deal of instability driven convection across the area, and even a couple lightning strikes noted along the crest of the nrn Sangres as of 21z. For this evening and overnight, HRRR suggests one last band of heavier precip developing over Fremont/El Paso/Pueblo counties toward 00z, which seems plausible given increasing convection over the Sangres/Wets late this afternoon. Will keep relatively high pops in place over/downstream of the eastern mountains to account for this, then precip fairly quickly fades away after sunset. Not expecting big snow accums, but a few spots along/west of I-25 could get a quick inch or two. Elsewhere, still a few more hours to go of scattered to numerous snow showers, and will hold on to current set of highlights into the evening. Latest look at mid level temps suggests column should stay cold enough for mainly snow this evening, with perhaps a rain/snow mix in areas south of the Arkansas River where surface temps are well above freezing. Some patchy fog likely over nrn El Paso county given continued sely upslope, though soundings and most numerical guidance begin to improve visibility after midnight as flow weakens and some slightly drier air begins to mix in. Expect bulk of any precip to be done by midnight, with just some lingering light snow through the night along the Continental Divide. Clouds may be slower to clear, especially over the plains where ely component to the surface flow persists. On Saturday, mainly dry across the area in the wake of departing trough, with only a few -shsn along the Continental Divide in the afternoon. Max temps will be warmer over the mountains and interior valleys, while temp forecast on the plains is rather problematic with easterly surface flow persisting for much of the day. Still expect I-25 corridor to warm with more sun, while areas close to the KS border where stratus may linger will stay mainly in the 40s. .LONG TERM...(Saturday night through Friday) Issued at 333 PM MDT Fri Mar 13 2020 Much of the extended period appearing to remain active, beginning Saturday night into Sunday morning and again possibly Sunday night into Monday morning. Southwesterly flow expected to remain in place for much of the weekend into early next week. In this pattern, a period of WAA appearing likely across much of the region, especially along the eastern plains. As conditions moisten or remain relatively moist, could first see light precip development Saturday night over parts of the lower elevations and plains especially with low level upslope flow in place. With forecast soundings showing this low level moisture along with some weak ascent, could see some light precip development. Most guidance is indicating this possibility, with developing some light qpf. With some increased confidence for this potential, did add pops to the forecast late Saturday night. At this point, any development is appearing to remain light and did add drizzle wording. With the potential for temps to be around freezing, did also include some freezing drizzle wording. Highest confidence for this potential is over the plains closer to the Kansas border, however, it is possible for this development to reach parts of the I- 25 corridor. Similar setup appearing possible again Sunday night, though upslope flow not expected at this time. Quiet and warm conditions expected on Monday for much of the area, with highs expected to rise into the 60s and 70s. This warmth looking to be brief, as a front expected to drop south across the region late Monday into Tuesday. In it`s wake, guidance showing easterly upslope flow to support our next chances of precip during this time frame, and possibly lingering into early Wednesday. Not as much cold air with this front, so precip should stay mainly rain but can`t rule out a rain snow mix. By the middle of next week, will begin to focus on a potential larger system to move across the western CONUS and towards the region. Definitely some big difference among guidance on overall evolution and timing of this system. However, more widespread precip chances are appearing more probable by middle/late of next week. Not only is wintry precip expected, but potential increases in moisture and instability could support thunder across parts of the area. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 333 PM MDT Fri Mar 13 2020 At KCOS, still some fog and flurries at the terminal late this afternoon, with IFR/LIFR conditions persisting. Still one more period of heavier snow 23z-02z before precip ends later tonight. While model guidance suggest cigs/vis improving to MVFR late this evening, suspect clearing/improvement will be much slower given southeast surface winds, and will hold on to lower clouds until winds weaken toward 12z Sat. VFR then expected Sat. At KPUB, MVFR cigs will persist, with a brief period of IFR cigs/vis due to snow showers possible 23z-02z. Slowly improving cigs then expected late tonight, with VFR conditions on Sat. At KALS, still a risk of a brief shower with MVFR cigs/vis into the evening, before precip ends 03z-06z. VFR conditions then expected overnight into Saturday. && .PUB WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until midnight MDT tonight for COZ068. Dense Fog Advisory until 9 AM MDT Saturday for COZ084-085. Winter Weather Advisory until midnight MDT tonight for COZ073- 075. && $$ UPDATE...HODANISH SHORT TERM...PETERSEN LONG TERM...RODRIGUEZ AVIATION...PETERSEN