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

Area Forecast Discussion
National Weather Service La Crosse WI
1015 PM CDT Thu Mar 19 2020 .SHORT TERM...(This evening through Friday) Issued at 216 PM CDT Thu Mar 19 2020 Water Vapor imagery this afternoon depicts two distinctive upper- level systems - a positively tilted shortwave trough over the Central Plains and a large scale trough located over Manitoba. The southern stream system is responsible for the widespread rain/storms we are experiencing this afternoon as a surge of moisture transport, precipitable water values of 0.75 to 1.00 inch, and warm air advects northward ahead of it. This surface low will continue to lift into the the Great Lakes Region tonight, bringing with it continued chances for showers and some storms, mainly south of Interstate 90. As the low progresses further north, the northern stream trough will dive southeastward and push the southern stream system eastward while they phase together. Deterministic models started to agree on the eastward shift yesterday, with high res models jumping on board today. Because of this, the threat for strong to severe storms continues to be shunted further east. The latest RAP runs and 19.12Z HREF are also on board with this as they continue to nudge the better ingredients further south and east of the local area where the warm sector will be located. MUCAPE values on the order of maybe 200-400 J/kg at best look to just barely reach portions of far northeast Iowa and southwest Wisconsin this evening. This, paired with mid-level lapse rates of 6-7 C/km and some influence from the left exit region of an upper-level jet may be just enough to produce a strong storm or two, with hail and lightning being the main threats of concern. However, confidence continues to increase that the threat for a strong storm or two is rather low. Per collaboration with SPC, have shrunk the slight risk to only cover extreme southern parts of CWA. Our taste of springtime rain showers and storms on the first day of Astronomical Spring will be brief as the northern stream system plows through the area tonight, bringing with it colder temperatures and some mid-March snowfall. Precipitation will transition from rain to snow as temperatures cool and a strong low to mid-level frontogenetic band develops. Generally around 1-2 inches of snowfall look likely across areas near and north of Interstate 90, with lesser amounts further south. The 19.12Z HREF continues to have a few members depicting some isolated higher amounts across parts of southeast Minnesota, which seems possible with the strength of the frontogenetic band. However, exact placement of said higher amounts will need to be refined once the band of snow develops later this evening. Although the entire area may not see accumulating snowfall, any residual moisture on roadways from the widespread rainfall today may flash freeze as temperatures rapidly cool tonight. This may result in slippery spots and travel impacts for the Friday morning commute. Additional liquid accumulations from this afternoon into tonight look to range between 0.50 and 1.00 inch. This on top of what has fallen over the last few days will lead to rises on area rivers. .LONG TERM...(Friday night through Thursday) Issued at 216 PM CDT Thu Mar 19 2020 The upper level flow will become quasi-zonal after the passage of the system tonight. The models have been advertising a northern stream short wave trough dropping out of western Canada and moving across the Upper Midwest and the 19.12Z model suite continues this trend but has sped up the timing. This wave now looks like it cross the region Saturday night into Sunday and come with enough forcing to possibly produce some light precipitation. Because of the zonal flow, the moisture return ahead of the wave will be very limited and thus only some very light snow looks to be possible with this system. This system will then usher in a period of on/off precipitation chances that will continue through much of next week. The next system in the northern stream looks to primarily stay across Canada with the southern tip of the troughing coming close enough to the Upper Midwest to possibly produce some more light precipitation Sunday night and Monday. After the passage of this system, the overall agreement between the models starts to decrease on timing/placement/strength of subsequent systems. The general idea is that an upper level low over the Pacific this weekend will move onshore and weaken as another system drops south out of the northern Pacific. The remains of this system should then move across the Midwest somewhere in the Monday night through Tuesday night time frame. The precipitation chances look to be higher with this system as the forcing will be stronger and should have more of a direct impact on the area. Behind this system, the upper level flow looks to become southwest as the norhtern Pacific system continues to drop southeast into Desert Southwest. The models are suggesting that various short wave trough coming out in the this southwest flow will maintain the precipitation chances into late next week. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 1015 PM CDT Thu Mar 19 2020 IFR conditions with a period of -SN is expected at KRST with -RA changing to -SN at KLSE. Lingering snow should exit by 09 to 11Z with conditions trending VFR during the day with clearing skies. Winds will gust to 25-35 kts into early Friday before slowly diminishing. && .HYDROLOGY... Issued at 216 PM CDT Thu Mar 19 2020 The system moving across the region tonight still looks to have the potential to produce some widespread rainfall amounts of 1 to 1.5 inches. A good share of this rain should be turned into runoff from still partially frozen ground and what is thawed, being saturated from earlier rains Tuesday night. Given this set up, expect rises to occur on almost all area streams and rivers with the possibility of flooding occurring. Right now, the highest probabilities for flooding look to be for the tributaries across western Wisconsin and maybe a few in northeast Iowa. Most of this should be minor flooding, but contingency forecasts with maximum potential rainfall indicate moderate flooding is not out of the question. The mainstem of the Mississippi River will also see rises with some minor flooding possible next week. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...NMB LONG TERM...04 AVIATION...JM HYDROLOGY...04
National Weather Service Hastings NE
140 PM CDT Thu Mar 19 2020 ...WE ARE NOW MONITORING RADAR AS SCT TSTMS ARE DEVELOPING... .SHORT TERM...(This evening through Friday) Issued at 140 PM CDT Thu Mar 19 2020 Plan to keep this brief to maximize availability for monitoring radar. Be sure to follow SPC SWOMCD`s and any Watches as svr tstms could occur before sunset. Aloft: RAP tropopause analyses/WV imagery/aircraft wind obs indicated a trof over the Wrn USA with a ridge over the GlfMex. A potent shrtwv trof was embedded within the Wrn trof over CO and lifting NE into NEB/KS. This trof will cross the CWA this eve. Behind this trof...a minor shrtwv ridge will arrive by dawn Fri with low-amplitude WSW flow evolving overhead Fri. Surface: 998 mb low pres was along the CO-KS border with a strong warm front extending ENE thru Srn NEB into IA. This front does bisect the CWA just N of the KS state line. A strong cold front was over the Nrn plns. This front will move S this afternoon. The 2 fronts will merge and the combined front will accelerate SE away from the area this eve. The push will be provided by a strong 1040+ mb high over Cntrl Canada which is sinking S. This will strengthen the pres grad over the rgn tonight. The low will weaken and a new low will evolve over the GtLks tonight...while the high sinks into the Nrn Plns. The high will remain there tomorrow. Rest of this afternoon: Cldy N of the front and mostly sunny to the S. Expect sct tstms to form espcly near the front. Some storms could be svr. This will be a low CAPE/higher shear scenario. Mainly looking like a hail and gusty wind type event. The risk of a tornado is low as winds will be unidirectional in the warm sector. Best shear will be on the cold side of the front. Tonight: Rain changes to brief 3-6 hr period of snow as cold air slams in here. Snow will essentially be done by midnight or shortly thereafter. Windy! N winds 25-35 mph with G50. Rapid clearing from N-S after midnight. Fri: Sunny. Cold. Diminishing winds. .LONG TERM...(Friday night through Thursday) Issued at 140 PM CDT Thu Mar 19 2020 Aloft: No change in the longwave pattern we`ve seen since mid Nov...with a trof over the Wrn USA and a ridge over the E. This will generally translate to continued low-amplitude WSW flow over NEB/KS. A wk shrtwv trof is fcst to cross the rgn Mon night into Tue. The last 2 runs of global mdls are in good agreement that the flow will amplify some late next wk...with the flow turning SW Thu as the Wrn trof becomes mobile and gets closer. Surface: The Nrn Plns high will gradually move E thru the wknd with return flow developing here. A wk cool front is fcst to move thru Sun night. Multiple lows will then form over the Cntrl US/Can Tue-Wed. The two that will probably affect the CWA will be Mon night into Tue...with no cool air behind it...and then Wed night and there will be a cooldown behind that low. Temps: Normal daytime highs are low 50s. Temps will be at or above normal thru next Thu...mostly above normal. Precip: A couple chances for very light wintry mix or shwrs with embedded non-svr tstms. Am holding off on much elaboration due to impending tstm development this afternoon. && .AVIATION...(For the 18Z KGRI/KEAR TAFS through 18Z Friday) Issued at 140 PM CDT Thu Mar 19 2020 Significant Wx: IFR with sct +TSRA this afternoon. This afternoon: IFR CIGs and variable VSBYs between MVFR and IFR. Sct +TSRA are developing. Not sure either terminal takes a direct hit...but it`s psbl. NNE-N winds gradually incrs 25-35 kt. Confidence: Medium Tonight: IFR CIGs/VSBYs as rain changes to snow. Some wet accum psbl before ending around midnight. De-icing will be required. N winds increase to around 30 kt with G40-45 kt at times. Rapid clearing and becoming VFR after midnight. Confidence: High Fri thru 18Z: VFR. No clds at or below 10K ft. N winds gradually diminish to 10-20 kt. Confidence: High && .GID WATCHES/WARNINGS/ADVISORIES... NE...Winter Weather Advisory until 7 AM CDT Friday for NEZ039>041-046- 047-060-061. KS...NONE. && $$ SHORT TERM...Kelley LONG TERM...Kelley AVIATION...Kelley
Area Forecast Discussion
National Weather Service Grand Rapids MI
813 PM EDT Thu Mar 19 2020 LATEST UPDATE... Update/Aviation .SYNOPSIS... Issued at 236 PM EDT Thu Mar 19 2020 - Marginal risk of severe weather overnight - Windy and colder Friday && .UPDATE... Issued at 814 PM EDT Thu Mar 19 2020 The threat for severe storms seems to be decreasing from what we though earlier. If there were a threat it would be south of a arc from Holland to Battle Creek (more or less). I have just called SPC and they agree that the severe storm threat has decreased over Lower Michigan. The latest RAP model shows 2200 j/kg of mix layer cape where the storms currently are in Iowa, by the time that area gets to Michigan it`s more like 200 to 400 j/kg of Mixed layer cape. The trend in the SREF of the conditional probability of severe storms which on the 06z run had 20 pct into Southern Van Buren county, has now fallen with the 15z run to 5 pct over southern Van Buren County. The only thing to watch is the track of the surface low may be close enough to this area that we may see a few strong storms even so. My bottom line is the threat seems to be higher closer to I-80 than I-94. && .DISCUSSION...(This evening through next Thursday) Issued at 236 PM EDT Thu Mar 19 2020 - Marginal risk of severe thunderstorms overnight First batch of rain moves through this evening with some embedded thunderstorms in limited elevated instability. Then the dry slot moves in but surface based instability in the warm sector could help development of a line or small clusters of thunderstorms between midnight and 4 am, shown by some runs of the NMM, and ARW convective allowing models. Given strong shear profiles, any persistent and organized storms have the potential to produce wind damage. - Windy and Colder Friday Cold advection behind the front on Friday will mix down some winds in the 30 to 40 mph range and temperatures will tumble into the 30s with wind chills below freezing by afternoon. Some lake effect snow showers are possible across the northwest. Active wave train continues next week but any threat of significant impacts from severe or winter weather looks low. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 814 PM EDT Thu Mar 19 2020 Expect IFR conditions most of the night due to low ceiling and low visibilities. Once the cold front comes through for the most part MVFR cigs and gusty winds will prevail most of Friday during the day. There is the threat of a few thunderstorms between 03z and 08z but that threat is not all that high. I removed the VCTS from JXN and LAN and it`s questionable at MKG and GRR. If any of our TAF sites were to see thunderstorms, it would seem AZO and BTL would have the greatest risk. Even there the SPC SREF has between a 20 and 30 pct chance of a thunderstorm between 03z to 06z. A classic early spring storm is tracking through the Great Lakes this evening. The warm front has brought rain across our TAF sites with IFR conditions in rain, fog and low ceilings. The rain band will lift north of the TAF sites but scattered showers will likely continue through the evening. A area of convective showers is likely in the 03z to 08z time frame as the cold front moves through but based on the HI RES models that threat is more so over the southwest CWA than anywhere else. Once that is done expect low clouds and breezy conditions with strong wind shear near 2000 ft agl. Three is a risk the snow showers trailing the system could get as far south as MKG and GRR by mid morning Friday but the threat did not seem high enough to put in the TAFs. && .MARINE... Issued at 258 PM EDT Thu Mar 19 2020 No changes to the Gale Warning as gusts to 35 knots are expected Friday morning then decreasing in the afternoon. The Gale Warning could probably be downgraded to a Small Craft Advisory in the afternoon. Minor beach erosion and flooding is expected Friday morning but conditions should be improving as the winds decrease and begin to shift offshore during the afternoon. && .HYDROLOGY... Issued at 258 pM EDT Thu Mar 19 2020 We still expect about one half to three quarters of an inch basin wide average QPF tonight which would cause some rises to near bankfull on the mainstem rivers the next few days. At this point it does not appear that flooding is likely except in areas where some training of thunderstorms occurs. The potential for this is greatest in the Kalamazoo River Basin. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Lakeshore Flood Advisory from 8 AM to 8 PM EDT Friday for MIZ037- 043-050-056-064-071. LM...Gale Warning from 8 AM to 8 PM EDT Friday for LMZ844>849. && $$ UPDATE...WDM SYNOPSIS...Ostuno DISCUSSION...Ostuno AVIATION...WDM HYDROLOGY...Ostuno MARINE...Ostuno
Area Forecast Discussion
National Weather Service Gray ME
1015 PM EDT Thu Mar 19 2020 .SYNOPSIS... Low pressure passes off the New England coast tonight continuing light rain and drizzle. Rain showers and a few storms are possible tomorrow, then a cold front crosses late in the evening into the overnight hours. High pressure with colder and drier air arrives for the weekend through the start of next week. Rain or snow is possible late Monday into Tuesday morning. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... 1015 PM Update...Just a few minor adjustments to the going forecast as it remains on track. 745 PM Update...Little change to the going forecast for the next several hours. Areas of fog and drizzle will be the rule for most of the forecast area this evening and overnight. Have added a little bit of freezing rain to the western ME mountains as temperatures in some spots are hovering around 32F around 2000 FT in elevation. Not expecting anything more than patches of it, so not advisory at this time. Previously... Humid and dreary weather continues through the evening and overnight hours as low pressure lingers off the New England coastline. At the current hour, RAP analysis places the center of low pressure just south of Nantucket with model consensus bringing it ENEward through the Gulf of Maine overnight. This keeps onshore flow going with light rain and drizzle over the coastal plain, aided by a 40kt h925 LLJ. While the temperature inversion keeps most of the energy well aloft, a few gusts around 20 kts are possible along the immediate coast this evening. Looking at the broader picture, column thickness continues the days-long upward trend as strong southwest flow increases aloft. Upstream, a trough extending from the Hudson Bay region down into the southern Plains tracks a surface low across the northern Great Lakes basin tonight. Warm frontal forcing ahead of it brings the next round of rain showers into our area from the west just before dawn. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... Late Friday morning, a surface warm front pushes north across New Hampshire and into southern Maine with scattered shower activity. The front is forced north by a surging mid-level jet of around 50-60 kts at h850. In spite of afternoon temperatures rising well into the 60s to near 70 in the warm sector, BUFKIT soundings suggest strongest winds aloft remain above the mixed layer in the warm sector. A few wind gusts in the 20-30 kt range are possible should breaks in the clouds allow the surface to warm, but in general momentum transfer in convection would be the best bet to mix strong wind gusts to the surface. Regarding convective chances...low-topped storms are possible with both warm frontal forcing and eventually with cold frontal passage. In general storms won`t be widespread, and I`m certainly not expecting widespread strong storms. Though, there is plenty of wind energy aloft to drive lines of gusty showers with some rumbles of thunder. Heavy rainfall is also likely in convection as PWAT tops 1.25" over much of the area. Surface low pressure tracks into eastern Quebec by the end of the day, dragging a cold front across New England late in the evening, ushering in a dry trend after what may be one last line of showers and storms. In general though storm chances decrease with the diurnal trend. Cold advection behind the front will allow for better mixing of gusty winds to the surface, maxing out on the order of 25-30 kts. Upslope rain showers switch to a brief bout of snow showers over the mountains before drying entirely by dawn. && .LONG TERM /SATURDAY THROUGH THURSDAY/... The 500 MB hemispheric pattern is poised to provide something we haven`t seen much of over the winter, downstream blocking over the NO Atlantic and Europe, although it maybe too far downstream to have a significant effect on nrn New England. Still, it will provide several rounds of precip, and temps bouncing between normal and abv normal, once the cold sfc high moves out after the weekend. The weekend will be mainly sunny and cold as high pressure moves in behind the low exiting to our NE across maritimes. IT`ll still be breezy on saturday, but winds should subside somewhat on Sunday. Highs on Saturday will be in the 30-35 range in the mtns and 40-45 in the south. Sunday, although less windy, will be a little cooler, as mixing will be limited with highs in the low to mid 30s N, to around 40 in the south. Monday should start off decent, but approaching compact 500 MB wave should produce low pressure offshore. System is potent but small, and will be fast moving, so QPF looks light, but p-type could be an issue Mon night into Tuesday morning, especially in inland areas of ME and central and nrn NH. Should see a brief break on Wed as high pres builds in with temps warming up some. The end of the looks unsettled attm, as several waves move through lightly cyclonic flow aloft. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... Short Term...Onshore flow keeps low ceilings into into tonight with -RA/BR/DZ/FG reducing visibility especially along the Maine coast. CIGS will tend to fill in and lower to IFR and LIFR, especially as a warm front approaches from the south Friday morning. A strong jet aloft brings a warm front from south to north late Friday morning while also producing a period of SWerly LLWS into the afternoon. Scattered showers and a few storms are possible Friday, then a cold front crosses late in the evening with gradual improvements overnight, except for at HIE where upslope flow continues MVFR into the morning hours. Long Term...Mainly VFR conditions expected Sat-Mon. Could see some flight restrictions in RA/SN Mon night into Tuesday. && .MARINE... Short Term...Low pressure off the New England coast increases seas over the waters and Casco Bay to 5-10 ft with wind gusts 20-30kts. Conditions briefly improve as low pressure pulls away Friday with scattered showers and a few storms possible, then a cold front crosses Friday evening with winds turning offshore and increasing seas again. Expect SCAs to persist through the entire short term period. Long Term...SCA winds/seas likely to persist through Saturday, but will begins to diminish Sat night, and should stay blo criteria into Monday. May need SCAs again Mon night or Tue. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 4 PM EDT Friday for ANZ150-152>154. && $$
Area Forecast Discussion
National Weather Service Marquette MI
747 PM EDT Thu Mar 19 2020 .SHORT TERM...(This evening through Friday) Issued at 456 PM EDT THU MAR 19 2020 A strengthening storm system will track from the Central Plains this afternoon into the Upper Great Lakes tonight as light rain transitions to wet, and at times, heavy snow this evening continuing into Friday morning, with several inches of wet heavy snow likely over the west and central U.P. tonight. Water vapor imagery and RAP analysis show a split flow pattern over western N America. In the southern stream, a mid-upper level trough is situated over the West Coast with a very well-defined shortwave moving through the Central Plains which will be the feature of interest for our forecast area tonight into early Fri as it races ne ahead of a northern stream shortwave dropping se toward the Upper Lakes. As the central Plains shortwave and associated sfc low lift into WI and then toward the Mackinac Straits tonight, winds will shift to the north and CAA will drop temps through the column, transitioning precip to snow across the region. Coupled upper jet structure with one jet max over northern Ontario and northern Quebec and another nosing into the mid-Mississippi Valley/Midwest will lead to strengthening fgen especially during the evening hours across the U.P. This strong forcing along with ample moisture should enhance pcpn totals in the late afternoon/evening hours. Widespread liquid equivalent precipitation of 0.75 to 1.00 inches is expected by Friday morning. Models have trended slightly farther east with the best area of heaviest synoptic pcpn moving through the central U.P. this evening. The challenge with the forecast will be determining when the changeover to snow occurs as models the last few runs have trended a bit colder with low level temps, and it looks like the change over to snow appears to be a few hours earlier this evening, supported by strong lift and adiabatic cooling. The window for heavy synoptic snow is relatively short, mainly this evening, over a 4-5 hour period. Current indications are for the changeover to snow to occur 23-00Z from MQT to Crystal Falls and west, then slowly change over from west to east over the remainder of the U.P late tonight through Fri morning. Lake enhancement will also play a key role tonight as strong northerly winds advect cold air with 850 mb temps lowering to around -16C by Fri morning over Lake Superior. Models indicate some lingering synoptic forcing over the lake into Fri morning which should enhance lake effect snow totals. The combination of snow, strong winds and blowing snow will continue to warrant winter weather headlines. Snow and wind will make travel difficult and also concerns for isolated power outages with the snow being very wet early on, weighing down trees and powerlines. Forecast snow amounts are generally 2 to 4 inches over the interior, 3 to 7 for the snowbelts and up to 8 in the highlands. Given the trend for heavier qpf to shift slightly farther east will keep winter weather advisories going over the west and south central counties, but have decided to upgrade advisories to winter storm warnings over Baraga, Marquette and Alger counties to account for the moderate to possibly heavy snow, gusty north winds 35-45 mph causing blowing snow and poor visibility later tonight into Friday. The Friday morning commute will probably be pretty miserable with the lake enhanced snow and blowing snow, especially for Highway M-28 from Marquette eastward. Will continue lake shore flood advisories/warnings as wave heights reach 12 feet in the west and 18 feet central late tonight into Friday, expect beach erosion along ice free shorelines and flooding in typical problem areas. Ice could also be pushed onshore. .LONG TERM...(Friday night through Thursday) Issued at 308 PM EDT THU MAR 19 2020 Over the next 7 to 10 days, strong positive height anomalies/ridging will be present over the N Pacific with the max anomalies varying btwn the Gulf of Alaska and the Aleutians, but mostly over the Aleutians. This will force troffing in the mean generally in the vcnty of the W Coast. Meanwhile, late season bitter cold air will expand across northern Canada under a large, deep mid-level low settling s into n central Canada. At this point, medium range guidance suggests upstream ridging will never become amplified enough to force this cold air s toward the Great Lakes. In any event, should be an active pattern across the Lower 48 as shortwaves round the N Pacific ridging into the western trof and then eject e and ne across the U.S. while other shortwaves swing around the large mid-level low dropping into n central Canada. One system will track ene across the area later today thru early Fri, bringing rain/snow. In its wake, strong high pres will provide a dry weekend. A little -ra/-sn will be possible early next week as a weak shortwave swings along the U.S./Canada border region. A stronger wave will eject from the western trof heading into the midweek period, but it should pass far enough s of the area so that the main pcpn shield passes by to the s of Upper MI. During the late week period, recent days model runs have at times indicated that another wave ejecting from the western trof would track into the Upper Lakes, providing the potential of significant pcpn, rain and/or snow. Will be something to monitor down the road. In the meantime, models will struggle with timing of ejecting waves out of the western trof, the amplitude/timing of shortwaves swinging around the deep Canadian mid- level low, and the potential interaction btwn the 2 streams of flow. As for temps, blo normal temps will follow the system passing tonight with Fri the coldest day. Temps will moderate back toward normal for Sun. During next week, temps will likely be a little above normal on most days. Beginning Fri night, strong sfc high pres over the Northern Plains will shift east toward the western Great Lakes. Low-level n to nw flow ahead of the high and 850mb temps of -15 to -18C across Lake Superior support the potential of LES, but only into the eastern fcst area under longer fetch and colder air. Typical for late season LES, fcst soundings show a fairly pronounced inverted-v look (a negative for LES) due to the building mixed layer that occurs during the daytime upstream of the lake. Since the DGZ occupies the total cloud layer, capped by an inversion around 5kft, should be able to generate some flurries or a few -shsn from near Marquette eastward Fri night and perhaps lingering into Sat morning. To the w, potential is there for a cold night. If lake clouds are limited, combination of a dry air mass with precipitable water around 30pct of normal and winds diminishing toward calm will allow for a strong radiational cooling night. Opted to drop temps toward the bias corrected CMC which is normally a superior performer in radiational cooling situations. So, fcst reflects lows around zero in that area. If it ends up being a clear night, temps could easily drop to -10F. High pres moves across the area on Sat and shifts to southern Quebec on Sun, providing a dry period. Highs in the mid 20s to the lower 30s on Sat will rise to the lower 30s to around 40F on Sun. Shortwave swinging along the U.S./Canada border will bring a chc of -shsn Sun night and -shsn/-shra on Mon. There will be a couple more opportunities of some rain/snow next week. Fcst currently reflects rather broad coverage of chc pops due to timing uncertainties, but right now it appears Wed night/Thu has the best chc of some pcpn. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 737 PM EDT THU MAR 19 2020 KIWD and KCMX have already switched over to snow, with snow mixing in, if not already entirely switched over at KSAW by the time this is read. For the duration of the night, the main issues for aviation interests will be the reduced ceilings, the reduced visbys, and soon to move in, the increased northerly winds that will produce noteworthy gusts, especially closer toward daybreak. Expect some improvements after sunrise on Friday, although snow showers will still linger in and around the terminal areas. By later in the afternoon, conditions across the board will improve. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 456 PM EDT THU MAR 19 2020 Low pres will streak from Colorado today, across the Straits of Mackinac tonight and into southern Quebec on Fri. With strong high pres building into the Northern Plains in the wake of the low, N gales of 35-45kt will develop from w to e across Lake Superior tonight, continue into Fri morning, then diminish to blo gale force from w to e Fri aftn thru early Fri evening. The strongest winds will occur across a wide swath of central Lake Superior. Not out of the question that few a storm force gusts could occur late tonight/Fri morning. Along with much colder air surging into the area, expect hvy freezing spray for all but far western Lake Superior on Fri. Winds will become light for Sat, under 15kt, as high pres passes across the area. S to SE winds will then increase to 15-25kt across much of Lake Superior Sun into Sun night as the high exits and a weakening low pres trof approaches. Winds will then diminish some on Mon as the trof dissipates while crossing Lake Superior. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Winter Weather Advisory until 2 PM EDT /1 PM CDT/ Friday for MIZ001>003-009-084. Lakeshore Flood Advisory from 2 AM to 2 PM EDT Friday for MIZ001>003. Lakeshore Flood Warning from 5 AM to 8 PM EDT Friday for MIZ005- 006. Winter Storm Warning until 5 PM EDT Friday for MIZ004>006. Winter Weather Advisory until 7 AM CDT Friday for MIZ010-011. Lake Superior... Heavy Freezing Spray Warning from 6 AM to 8 PM EDT Friday for LSZ243>245-248>251-263>267. Gale Warning from 7 AM to 8 PM EDT Friday for LSZ251-267. Gale Warning from 2 AM to 8 PM EDT Friday for LSZ245>250-265-266. Gale Warning from midnight tonight to 8 PM EDT Friday for LSZ243- 244-264. Gale Warning from midnight EDT /11 PM CDT/ tonight to 4 PM EDT /3 PM CDT/ Friday for LSZ240>242-263. Gale Warning from midnight EDT /11 PM CDT/ tonight to 11 AM EDT /10 AM CDT/ Friday for LSZ162. Lake Michigan... Gale Warning from 7 AM to 8 PM EDT Friday for LMZ221-248-250. && $$ SHORT TERM...Voss LONG TERM...07 AVIATION...lg MARINE...Voss
Area Forecast Discussion
National Weather Service Pueblo CO
926 PM MDT Thu Mar 19 2020 .UPDATE... Issued at 922 PM MDT Thu Mar 19 2020 Updated to take down highlights across the Pikes Peak region... Heavier snow has come to an end and visibility has improved in web cams across northern El Paso county. Therefore have taken down the Blizzard and Winter Storm Warning at 9 PM. Light snow continues to fill in across the southeast mountains and adjacent lower slopes as low level flow shifts around to the northeast. Not much showing in web cams yet along I-25 and Highway 160 over La Veta Pass, though VTP sensor is showing pretty low vis in +SN in the past hour. Will maintain winter weather advisories for the Sangres for a bit longer to account for some patchy heavier snow. HRRR has this diminishing towards 06z so suspect that highlights will be taken down around then. -KT UPDATE Issued at 605 PM MDT Thu Mar 19 2020 Updated package to allow headlines out west to expire. Still snowing out that way, but visibility in web cams have improved and additional snowfall will be light. -KT && .SHORT TERM...(This evening through Friday) Issued at 303 PM MDT Thu Mar 19 2020 ...Storm to continue into this evening... Currently... Major winter storm affecting parts of the region at this hour. So far the biggest winner has been Woodland Park with 10 inches. USAFA has observed blizzard conditons, with general 4-6" amounts in parts of N El Paso county. Radar at 2 pm continues to show heavy snow falling across far N El Paso county, with snow intensities decreasing a bit farther south due to downsloping winds off the Palmer Divide. Over the remainder of the plains, it was quite windy although the winds have slackened off a bit from earlier today. Far southeast CO mostly sunny and relatively mild, albeit it was windy. Temperatures were in the 60s over far southeast CO while they were in teh U20s over N El Paso county. San Luis Valley (SLV) had temps in the 40s. Rest of today into tonight... Blizzard conditions will likely continue across far N El Paso county (crest of Palmer Divide) into the evening hours, with heavy snow and wind gusts in the 35 to 40 mph range. Snow farther south will gradually decrease as downslope component overcomes synoptic lift associated with the cyclone. Another area of concern will be the east slopes of the S mtns as guidance shows some decent upslope developing later today into tonight, and we will likely see a few inches of new snow this evening. As for winds, winds will transition from strong NW to modest northerly flow over the plains tonight, with northeasterly winds closer to the mtns. Temps tonight will fall into the upper teens to L20s across the plains and valleys and single digits and 10s in the mtns. Over the remainder of the high terrain, unsettled conditions will continue with the trough lagging back, and this will keep a chance of snow showers over the higher terrain through the night. Tomorrow... Plains should be primarily dry through the day, although I cant rule out some snow showers rolling off onto the adjacent plains during the afternoon. Temps over the lower elevations tomorrow will be cool, with readings in the 30s and 40s. With high pressure building down the High Plains, a synoptically induced upslope flow will develop. Over the mtns it will be more active. With troughieness still to our west and the jet just to our south, weak upward vertical motion will occur within a rather moist airmass. This should allow snow showers to continue across the region, especially across the mtns along the CONTDVD. A few inches of new snow will be possible tomorrow over the higher terrain. Temps over the valleys tomorrow will be in the 40s valleys and 20s mtns. /Hodanish .LONG TERM...(Friday night through Thursday) Issued at 303 PM MDT Thu Mar 19 2020 Friday night-Sunday...Moderate west to southwest flow aloft progged across the region through the weekend with the latest models continuing to indicate an embedded short wave translating across the southern Rockies through the day Saturday and another embedded wave translating across the northern Rockies on Sunday. With that said, isolated to scattered showers over and near the higher terrain Friday afternoon to diminish and end through the evening, with more afternoon showers across the higher terrain expected Saturday afternoon, with a showers, and a few possible thunderstorms, developing across the southern I-25 Corridor through the far southeastern plains Saturday afternoon and evening. On Sunday, drier conditions expected across most of the area, save for shower chances across the central mountains Sunday afternoon. Should see temperatures warming back to near seasonal levels through the period. Monday-Thursday...Moderate westerly flow aloft progged to continue across the region into the middle of next weak, with a few embedded short waves translating across the region. This will keep isolated to scattered pops across the higher terrain, especially along the ContDvd, with mainly dry and breezy conditions across the plains. With temperatures expected to be at and slightly above seasonal levels, could see near critical fire weather conditions at times across the plains. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 303 PM MDT Thu Mar 19 2020 Unsettled conditions are expected tonight over the greater southern Colorado region and this will keep clouds and snow showers possible, along with occasional low cigs at the taf sites. The strong gusty winds at the taf sites will decrease this evening, with flow becoming upslope late tonight. This may induce some lower cigs over KCOS and KPUB late tonight. Snow showers over KALs tonight may bring in some brief periods of MVFR. For tomorrow, morning MVFR/IFR conditions at KCOS and KPUB should give way to VFR by mid to late morning. Passing snow showers will be possible at KALS tomorrow. && .PUB WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until midnight MDT tonight for COZ072>075. Winter Weather Advisory until 6 AM MDT Friday for COZ058>061-063. && $$ UPDATE...KT SHORT TERM...HODANISH LONG TERM...MW AVIATION...HODANISH
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Friday) Issued at 324 PM CDT Thu Mar 19 2020 The region undergoes a rapid change from summer to winter weather in the next 24 hours. As of 20Z, still monitoring far northern and northeastern Kansas near the triple point of an rapidly advancing dryline and warm front for convective development. The warm front current extends from near Hebron to Nebraska City, with the leading edge of the dryline extending southeastward from Republic to Lyon counties in low-level water vapor imagery. There is only a few more hours remaining before the warm, moist air is pushed east of the forecast area, and much of the severe weather with it. The west- to-east oriented CU field along and south of the warm front has become increasingly agitated in the last hour, with multiple convective cells developing and tracking northward over the front and into Nebraska. Despite ample destabilization in the warm sector ahead of the dryline, the veered wind profile ahead of the boundary minimizes the amount of convergence ahead of it. The lack of any appreciable CU along this boundary is a strong indication of just how little lift it is providing. Will continue to monitor the dryline as it moves through, but with continuing runs of the HRRR devoid of any significant convective signatures and satellite signatures very unimpressive, any threat along this line is INCREDIBLY conditional. The best severe threat is more likely closer to the warm front in southeast Nebraska. The overall warm sector CAPE/shear environment would support supercellular structures, if any storms do manage to form. Did cancel the eastern portion of the wind advisory for this afternoon given that the deepest mixing should be confined to areas along and west of the Flint Hills. The going wind advisory for this afternoon will likely be ended around 23 or 00Z depending on how fast conditions improve ahead of the approaching cold front. A very high fire danger also exists along and west of the Flint Hills this afternoon owing to deep mixing and RH values falling to 25 to 30 percent. As the upper level pattern shifts eastward, the surface low responds by advancing across the forecast area, dragging a sharp cold front across the region early tonight. Southwest winds lessen ahead of the front, but quickly increase out of the north to 20 to 30 mph with gusts over 40 mph at times through the night. Did issue a wind advisory for tonight with the combination of a strong pressure gradient and differential CAA through the BL keeping winds going throughout the night. Temperatures nose dive behind the front with the decaying deformation zone drifting through overnight as well. Can`t rule out some light precip as this band of moisture moves through, but impacts should be negligible. Wind chills by Friday morning fall into the single digits to teens and temperatures only recover into the 20s to low 30s during the day. .LONG TERM...(Friday night through Thursday) Issued at 324 PM CDT Thu Mar 19 2020 After a cold start to the weekend, a moderating pattern settles in through the middle of the week with multiple rounds of precipitation possible. The mean west coast longwave trough characteristics vary over the course of the extended period, but for the most part the trough remains in place for the forecast period. This will promote both a moderating west to southwest flow pattern and a series of energy lobe ejections that will bring chances for precipitation. The first such system arrives Saturday night into Sunday, and the next Monday into Tuesday. The details of these systems are still a bit too uncertain to hash out at the present time. Highs rebound back into the 40s and 50s for Sunday, reaching back into the 60s early in the week and even possibly the 70s by midweek. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 721 PM CDT Thu Mar 19 2020 Expect VFR conditions at across the terminals for most of the evening hours. a Surface cold front will move across the area after 3Z and stratus with MVFR ceilings of 1000 to 1500 feet will over spread the terminals during the late evening hours towards 6Z FRI. There may be low-level windshear of 30 KTS ahead of the front early this evening. Behind the front, north winds will increase to 20 to 30 MPH with some gusts of 30 to 40 MPH. && .TOP WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 5 AM CDT Friday for KSZ008>012-020>023- 034>036. && $$ SHORT TERM...Skow LONG TERM...Skow AVIATION...Gargan