Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/28/20

Area Forecast Discussion
National Weather Service Bismarck ND
957 PM CDT Mon Apr 27 2020 .UPDATE... Issued at 957 PM CDT Mon Apr 27 2020 Scattered rain showers continue across portions of southwest and south central North Dakota this evening. Linton and Fort Yates NDAWN stations have both reported a few hundreths of precipitation, and the Linton ASOS also reported moderate rain for a bit, so increased POPs in the south central in line with the better area of radar reflectivity associated with the reported rain. Kept POPs to the west lower since haven`t seen any reports of rain. Went ahead and took out the chance for isolated thunderstorms for the night since it`s been a few hours since we`ve seen any lightning close to the forecast area. Otherwise only minor changes to the forecast with this update. UPDATE Issued at 655 PM CDT Mon Apr 27 2020 Rain was reported at both the Hettinger ASOS and Hettinger NW NDAWN station from 22 to 23Z, so have some confidence that precipitation shown on radar is making it to the ground in at least far south central North Dakota. Our 00Z RAOB shows very dry air up to about 10K feet, but we did see rain on windshields here at the office, so guessing there will still be some very light rain falling in places before the atmosphere becomes more saturated leading to more persistent rain showers. Updated POPs with the latest high- res guidance, but no major changes with timing or location. There was some lightning in northwest South Dakota, so kept chance of isolated thunderstorms in for this evening. && .SHORT TERM...(This evening through Tuesday) Issued at 217 PM CDT Mon Apr 27 2020 A strong frontal passage will bring gusty northwest winds and possibly critical fire weather conditions to much of western North Dakota on Tuesday. Winds gusting up to 50 mph and minimum relative humidity values in the low 20s are expected in the southwest portion of the state. This afternoon, weak surface pressure falls were ongoing over western South Dakota and southwest North Dakota as a surface low deepened in response to a shortwave detected on water vapor imagery over northern Idaho and western Montana. As this shortwave continues to propagate through quasi-zonal this evening, increasing low level convergence should develop precipitation in far southwest North Dakota and move east through the night. Mid- level lapse rates in the 7-7.5 C/km range were advecting into our southwest. Atop a well-mixed and moisture deficient boundary layer instability values will be on the low end, but possibly enough for updrafts to form with lightning potential this evening. In the case that a more rigorous thunderstorm is able to develop, the inverted-V profile in forecast soundings may contribute enough acceleration of descending air parcels to produce some gusty winds. Upstream of the aforementioned shortwave, another mid-level shortwave was detected over the Pacific Northwest. This wave is expected to drop southeast and intensify under the influence of the left exit region of a 120 kt jet nosing in from the northwest. As western North Dakota is placed under the brunt of the post- frontal northwest flow regime, surface winds are expected to increase through the morning as efficient momentum transfer becomes more prevalent in an increasingly mixed boundary layer profile. Wind gusts should be greatest and approaching 50 mph in the southwest portions of the state. Additionally with another passage of dry air relative humidity will be low once again. Blending in RAP dew point guidance, which has performed well in high mix- out expected days, relative humidities down to 20 percent were added to the forecast. However high-resolution ensemble guidance (HREF) shows a healthy potential for even lower dew points and relative humidities. So while a Fire Weather Watch was issued to cover this potential, the coverage and magnitude of critical fire weather conditions certainly has the potential to increase. Scattered showers and possibly thunderstorms should develop as the mid-level low becomes more closed and wrap-around moisture with ongoing lapse rate advection develops instability during the day. 12Z NAM and 18Z RAP guidance advertises 500-1000 J/kg of MLCAPE which seems reasonable. Weak mid-level flow producing low shear values should prevent any severe thunderstorm concern. Between precipitation and the post-frontal air mass, high temperatures will be relatively cooler with temperatures in the 60s expected. .LONG TERM...(Tuesday night through Monday) Issued at 217 PM CDT Mon Apr 27 2020 A warming trend is expected for the middle of the week with highs on Thursday of around 80 possible in the western portion of the state. Chances for precipitation return late in the week through the weekend. A seasonably strong ridge is forecast to build over the Intermountain West by Wednesday morning. Stiff mid-level height rises and subsidence are expected with a surface high forecast to drift over the Dakotas through the day Wednesday. We should expect generally light winds with mostly clear skies and highs in the 60s and 70s. The upper level ridge axis will center over the Northern Plains on Thursday with warm air advection at 850mb and southerly surface flow expected to boost highs to what should be the warmest of the forecast period. Widespread 70s with areas of the west reaching around 80 are forecast. Guidance remains consistent in driving a shortwave trough over the ridging pattern Thursday night through Friday, bringing chances for showers and thunderstorms. With the high pressure pattern locked in to our south it is reasonable to say at this point best chances for precipitation should be in the northern portions of the state, with more uncertainty further south. 12Z GFS/ECMWF do hint at some instability developing ahead of the frontal passage expected on Friday, with potential for stronger thunderstorms dependent on still an uncertain wave timing and amplitude. Deterministic and CIPS ensemble guidance displays mean troughing in place over the Hudson Bay region with northwest cyclonic flow over the Northern Plains through the weekend. A relative cool-down with periodic chances for precipitation will accompany this pattern. Though details are currently fuzzy, guidance is consistent in bringing a stronger low through the region early next week with increased chances for precipitation in the NBM. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 655 PM CDT Mon Apr 27 2020 Scattered showers are expected to continue across parts of southern North Dakota through 12Z, with isolated thunderstorms possible. VCSH included in KBIS/KJMS but overall confidence in timing and location is low. More showers are possible on Tuesday as a cold front moves through the area, with the best chance of showers at KMOT/KJMS Tuesday afternoon. Winds will shift to be northwesterly behind the front, with the strongest winds expected in southwest North Dakota, gusting as high as 40 knots. && .BIS WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Tuesday afternoon through Tuesday evening for NDZ017-018-031>033-040-041-043-044. Wind Advisory from 9 AM to 8 PM MDT Tuesday for NDZ031>033-040- 041-043-044. && $$ UPDATE...MJ SHORT TERM...AE LONG TERM...AE AVIATION...MJ
Area Forecast Discussion
National Weather Service Caribou ME
1040 PM EDT Mon Apr 27 2020 .SYNOPSIS... Low pressure will slowly track well south of the Gulf of Maine overnight. High pressure build southward from Quebec tonight later Tuesday into Wednesday. Another low will approach the area from the west Thursday and cross the region later Friday. && .NEAR TERM /THROUGH TUESDAY/... 1040 PM Update...Pops were adjusted to match the latest radar trend showing some light precip backing into Maine from New Brunswick. The trend was to adjust the higher pops toward the coast. The latest RAP showed precip trends weakening and shifting s overnight w/the convergence weakening. Hrly temps were adjusted for current conditions. Given the clouds, only modest adjustments were made to the overnight temps. Previous Discussion... Steady northeast winds will continue through the night with generally cloudy skies. As the blocking high sets up over the area, the very dry air in northern zones will spread south tomorrow. Temperatures will be warmer without any precipitation and less cloudiness. A deep mixed layer is expected tomorrow which will ensure lower dew points than guidance and stronger winds. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... Sfc low wl be well south of Labrador by the start of the period. Sfc ridge axis wl be building twd the CWA fm Canada with axis bisecting the area by 12z Wed. Skies wl be clearing late and winds near calm may allow for radn`l cooling, especially over the northwest zones with mins dipping into the mid-20s. By Wed morning winds wl veer around to the south ahead of system mvg thru the Great Lks. This system is currently slamming into the British Columbia coast this afternoon. It wl head east thru the srn Prairie Provinces drg the day tomorrow before diving twd the MS Rvr Vly Wed afternoon. H5 ridge pumps up significantly ahd of this deepening low with 500 heights rising to 565+ leading to maxes u50s to nr 60 acrs a fair chunk of the region. Skies wl begin to cloud up as the system approaches on Wed night. By Thur morning all areas wl see cldy skies with pcpn mvg into the far wrn zones by daybreak. May see a rain/snow mix acrs the northwest as temps dip to nr 30F but quickly rebounding and going over to rain by mid-morning. Due to the extensive cloud cover and rain over the entire region high temperatures on Thu will be slightly blo normal with m/u 40s over the North Woods and around 50F over the remainder of the area. LLJ of 35-45 kts wl begin to kick in during the afternoon. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... Strong H8 jet rmns over the region Thu night into Fri. PW values wl be increasing thru the early part of the extndd pd with mid-level moisture mvg straight in fm the Atlantic. Area wl be in the RRQ of upr-lvl jet streak with dynamics likely leading to locally heavy rainfall. Cannot rule out possible thunder as well, which will lead to heavier rainfall amnts. Latest EC is giving widespread 1-1.25 inches amount Friday and Friday night. Expect lingering showers thru Sat night with another quick s/wv zipping acrs the FA thru the end of the pd. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... NEAR TERM: LLWS will affect all sites tonight. Gusty northeast winds will slowly diminish overnight. All sites will be VFR except coastal sites such as BHB and Machias will feature MVFR cigs with tempo IFR vis in snow showers tonight. All sites will be VFR Tuesday. SHORT TERM: Tue night-Thu morning...VFR. Light NE winds Tue night becoming SE Thu morning. Thu...Becoming MVFR all sites during the afternoon. S 5-10kts gusting to 15-20kts. Thu night-Sat...IFR all sites in rain, locally heavy. SE 10-15kts Fri becoming N Sat morning. Possible LLWS Thu night and Fri. && .MARINE... NEAR TERM: Gale conditions will end late tonight and a Small Craft Advisory will be needed in its place into midday Tuesday. The long period southerly swell will slowly diminish tonight. SHORT TERM: Below SCA conditions into Thursday morning before winds begin to increase out of the SE ahead of next system moving in from the west. Seas increase above 5ft in serly swell. SCA conditions through Fri morning. Gales possible during the day on the outer waters but gusts are marginal at this point. Seas remain elevated thru Sat afternoon with SCA likely continuing into Sat. && .FIRE WEATHER... Continued dry conditions in northern zones with low relative humidity and gusty northeast winds raise fire weather concerns for Tuesday. Expect a deep mixed layer which led to reduction of dew points below guidance and increased wind gusts. Temperatures will be a bit warmer into the lower 50s. A wetting rain that occurred today into tonight towards the coast mitigates concern for that area. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Gale Warning until 6 AM EDT Tuesday for ANZ050>052. && $$ Near Term...Hewitt
Area Forecast Discussion
National Weather Service Duluth MN
646 PM CDT Mon Apr 27 2020 .UPDATE... Issued at 536 PM CDT Mon Apr 27 2020 Issued a Marine Dense Fog Advisory along the North Shore and down into the Twin Ports area based on Satellite and web camera imagery. The HRRR keeps the low visibilities around till Tuesday morning. && .SHORT TERM...(This evening through Tuesday night) Issued at 309 PM CDT Mon Apr 27 2020 Isolated showers percolated over northern St. Louis County this afternoon ahead of a weak cool front. As one of the more vigorous showers (35-40 dBZ returns) passed over Orr, the AWOS reported a trace of rain. Cumulus were found over northern parts of the county and much of Koochiching County. Cumulus were smaller and more isolated elsewhere across the Northland. Think a few sprinkles will continue to percolate over northern Minnesota this afternoon ahead of the front. Otherwise, dry conditions are expected overnight. Areas of fog are possible overnight due to the combination of relatively light winds and clear skies, with morning rainfall. An area of low pressure will move eastward out of South Dakota and across northern Iowa and southern Minnesota Tuesday into central and southern Wisconsin by Tuesday evening. A secondary low may take shape over the Canadian Prairies tonight and move into northwest Minnesota on Tuesday. Between these two systems, much of the Northland will see at least a chance of showers. The best potential for rainfall is from the Brainerd Lakes area east into northwest Wisconsin. Rainfall amounts of one- to three- quarters of an inch are possible in those areas with lower totals farther north. With the passing area of low pressure on Tuesday, look for northeast winds over western Lake Superior. The onshore flow will keep temperatures cool along the shore and inland into the I-35 corridor. Precipitation chances will shift eastward as the southern low departs the area early Wednesday. Highs on Tuesday will reach the low and middle 40s near the Lake Superior shore to the middle 60s in Koochiching County. .LONG TERM...(Wednesday through Monday) Issued at 309 PM CDT Mon Apr 27 2020 Relatively quiet for much of the long term with a chance of showers or thunderstorms Friday afternoon through Saturday morning. A few lingering showers will depart Wednesday morning as a surface low over southern Wisconsin departs to the east. Cold air advection and cyclonic flow aloft may touch off a few isolated sprinkles Wednesday afternoon. High pressure settles over the region Wednesday night through Friday morning with quiet conditions expected. Temperatures will trend warmer for Thursday with highs in the 60s to low 70s except near the Lake Superior shore and portions of northwest Wisconsin where temps will be limited to the 50s. Onshore winds will be less of an issue for Friday and temperatures should be in the upper 50s to low 60s for most areas, except low to upper 50s along the North Shore. A compact shortwave trough will move across the Canadian Prairies and into northwest Ontario Friday and Saturday. A cold front will accompany the low and will set the stage for showers and thunderstorms over northern Minnesota Friday afternoon through Saturday morning. Temperatures will be similar on Saturday with highs in the 60s for most areas, except 50s along the North Shore and possibly a few 70s in the St. Croix River Valley. A few degrees cooler on Sunday as another cold front sags south across the Northland. There may be a few showers associated with that front. Highs will be in the upper 50s north to middle and upper 60s south. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 645 PM CDT Mon Apr 27 2020 VFR conditions to start the forecast off. Fog can be observed over Lake Superior and the light winds out of the east are gradually bringing it inland. Along the eastern portions of the Arrowhead a saturated surface combined with light mixing winds will stir up fog conditions overnight and into the morning hours. Look for DLH/HIB to have visibility reductions to IFR and possibly LIFR. Fog is expected to stick around into the later morning hours when the sun begins to disperse the low cloud, visibilities will then rise to MVFR. Tomorrow a low pressure system makes its way across the Midwest with its northern precipitation field clipping central MN and NW WI. Light rain showers are forecasted for BRD/HYR with ceilings dropping to MVFR in the afternoon for HYR. && .MARINE... Issued at 536 PM CDT Mon Apr 27 2020 A northeast wind continues to impact Lake Superior. Dense fog clouds can be seen on satellite beginning to migrate along the North Shore and down into the Twin Ports area. A dense fog advisory has been issued until Tuesday 10am. Winds will begin to pick up Tuesday afternoon with sustained winds between 10-20kts and gusts upwards of 25kts. With this increase in winds a Small Craft Advisory may be needed for portions of the southwest arm of Lake Superior. && .PRELIMINARY POINT TEMPS/POPS... DLH 37 47 36 55 / 10 50 30 20 INL 36 62 37 61 / 0 20 20 0 BRD 43 55 40 62 / 10 80 40 10 HYR 40 57 38 55 / 10 90 80 30 ASX 36 48 36 50 / 10 70 50 30 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. LS...Dense Fog Advisory until 10 AM CDT Tuesday for LSZ140>145. && $$ UPDATE...Britt SHORT TERM...Huyck LONG TERM...Huyck AVIATION...Britt MARINE...Britt
National Weather Service Hastings NE
650 PM CDT Mon Apr 27 2020 .SHORT TERM...(This evening through Tuesday) Issued at 328 PM CDT Mon Apr 27 2020 Forecast concerns in the near term revolve around precipitation chances and fire weather concerns on Tuesday. Tonight, a shortwave and associated cold front will approach the area from the northwest. This may allow a few showers and perhaps a weak thunderstorm or two to develop after midnight tonight through daybreak on Tuesday. That said, most spots will only see sprinkles, at best. Even the HRRR (which is usually on the higher end of QPF) only has a trace through Tuesday morning. As the front passes through the area on Tuesday, we will see gusty northwest winds develop behind it. Sustained winds will average around 25 MPH with gusts to around 40 MPH during the afternoon. For more information on the fire danger, see the fire weather section below. Models have now latched on to the idea that we will have some lapse-rate driven showers and possibly an isolated thunderstorm or two Tuesday afternoon and early evening. Severe weather is not expected, but additional mixing from any showers may provide localized enhancement to the already strong northwest winds. This activity should end by late evening, allowing skies to clear and temperatures to fall into the 40s. .LONG TERM...(Tuesday night through Monday) Issued at 328 PM CDT Mon Apr 27 2020 The bulk of the long-term forecast is relatively quiet. Wednesday will bring another day of fire weather concerns, albeit with lighter winds than on Tuesday. With high pressure overhead, Wednesday night will be the coldest night of the forecast period. Lows are expected to drop into the upper 30s to low 40s. Winds will then switch around to the south for Thursday and Friday as upper level ridging amplifies over the western half of the CONUS. By Friday, high temperature should push into the mid 80s to low 90s across the area. For now, its not looking like we`ll get to record-breaking territory, but it is a very warm start to May nonetheless. The ridge begins to break down as a weak perturbation moves in on Friday. As it does so, the GFS tries to generate some light showers in the area. That being said, better chances for rain and thunderstorms won`t arrive until Saturday or Sunday as a more substantial trough breaks down the ridge. Temperatures will trend cooler and closer to climatological normals through the weekend and into early next week. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday) Issued at 629 PM CDT Mon Apr 27 2020 VFR conditions are expected through the period although the period will not be uneventful with very gusty winds anticipated during the daytime hours Tuesday along with a small chance of thunderstorms late tonight and again during the afternoon hours Tuesday. While light and variable winds and VFR CIGS are the norm across the local area this evening...expect a cold front to bring additional cloud cover and a shift in winds to the local area overnight. Thunderstorm chances are expected to remain mainly north of both terminals overnight...but did include a VCTS at both sites aft 28/08Z just in case. After daybreak...expect winds to really ramp up out of the northwest...with gusts to 35KTS+ expected during the afternoon hours. In addition...a second disturbance will also bring back a small chance for thunderstorms late in the day Tuesday...and included an additional mention of a VCTS at both sites to account for this. && .FIRE WEATHER... Issued at 328 PM CDT Mon Apr 27 2020 Although we are starting to see a green-up across the area, there is still an abundance of dead grasses from the very wet 2019 season. These fuels will still support a wildfire threat given sufficiently strong winds or low RH. This threat is exacerbated by how dry we have been recently. Satellite-derived greenness data shows that our green-up is lagging a bit slower than normal, and observations across the area supported this...especially west of Highway 281. On Tuesday, the strong northwest winds will make any fires that develop very difficult to control. Therefore a RFW was issued for Highway 281 westward. Relative humidity may not be low enough to reach the 20 percent criteria across northern portions of the area, but it will still be dangerous fire conditions, nonetheless. Winds may also become erratic if any thunderstorms develop in the afternoon. Another round of fire weather concerns are possible on Wednesday. Winds will start to taper off in the afternoon, but humidity will likely be lower...possibly around 15 percent in southwestern portions of the area. && .GID WATCHES/WARNINGS/ADVISORIES... NE...Red Flag Warning from noon to 8 PM CDT Tuesday for NEZ039-040- 046-047-060>062-072>075-082>085. KS...Red Flag Warning from noon to 8 PM CDT Tuesday for KSZ005-006- 017-018. && $$ SHORT TERM...Mangels LONG TERM...Mangels AVIATION...Rossi FIRE WEATHER...Mangels
Area Forecast Discussion
National Weather Service Grand Rapids MI
1018 PM EDT Mon Apr 27 2020 LATEST UPDATE... Update .SYNOPSIS... Issued at 324 PM EDT Mon Apr 27 2020 - 7-day Forecast Overview - Tonight`s Rain - Mid Week Rain...possibly heavy...Tuesday night - Thursday - Few showers on Saturday && .UPDATE... Issued at 1018 PM EDT Mon Apr 27 2020 Have added areas of fog to the forecast later tonight as latest RAP fcst soundings indicate considerable low level moisture developing after the current light rain and mid clouds move out. The fog may become dense, but confidence too low at this time to go with a Dense Fog Advisory. Since the moisture will be shallow, expect any fog that develops to mix out rapidly early Tuesday. With enough sun, highs could easily top 70 but that will depend on extent of mid and high cloudiness. && .DISCUSSION...(This evening through next Monday) Issued at 324 PM EDT Mon Apr 27 2020 -- 7-day Forecast Overview -- We are looking at a fairly active pattern over the course of the next 7 days. A zonal flow in place to start the forecast tonight, quickly becomes amplified into mid week as a shortwave currently in the Pacific Northwest dives through the Northern Plains. By Wednesday the upper low is closed off and moving through the Great Lakes. Widespread rain that may become locally heavy is the main story in the forecast. The flow becomes zonal again over the weekend. Temperatures through the period will be fairly seasonable. Normals are highs around 60 and lows around 40 and we will not be far off from those numbers. The exception will be on Thursday when we will be solidly colder than normal with clouds, rain and a north flow. Highs may end up being around 50 or 10-15 degrees below normals. -- Tonight`s Rain -- The rain has already spread into West Central Lower Michigan as of 300pm. We are still thinking this rainfall will be on the order of 0.10 to 0.30 inches with a few higher streaks possible. The rain is associated with a quick moving shortwave in the northwest upper flow. The rain should come to an end overnight, probably around 300am. -- Mid Week Rain...possibly heavy...Tuesday night - Thursday -- The main show this week is the low pressure system that moves right through the forecast area. See hydro discussion below for the details, but a widespread soaking rain appears to be in the offing. We cannot rule out a rumble of thunder at times, especially Tuesday evening, but this will be more of a rain event as opposed to something that is highly convective. Both the GFS and the ECWMF deterministic runs have a sub 1000mb low moving through the area that will be interacting with PWATS that will be up towards 1.25 inches. The heaviest rain should come Tuesday night which is when an 850mb LLJ impinges on a warm front aloft over our area. These type of events seem to be predisposed to overperform, so we shall see. The upper low slowly spins through the area from Wednesday into Thursday as showery upper low precipitation turns into wrap around deformation zone precip. Suffice it to say we look wet from Tuesday evening into Thursday. -- Few showers on Saturday -- After Thursday conditions dry out considerably for the remainder of the forecast through next Monday. The exception is on Saturday when a moisture starved front pushes through the region. We are not expecting anything too heavy with this front. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 751 PM EDT Mon Apr 27 2020 Despite rain moving through the area this evening, VFR conditions are prevailing with cig heights around 5000 ft. The pockets of heavier rain are producing MVFR vsbys of 4-5 miles at times. All of this rain moves out later this evening, then the concern becomes the formation of low stratus clouds and fog overnight. Will feature a period of IFR/LIFR cigs/vsbys late tonight into early Tuesday, with the lowest conditions/vsbys expected west of LAN and JXN. The stratus and fog will mix out rapidly on Tuesday morning, leaving VFR weather. Some showers and perhaps a tstm may develop south of I-96 after 21-22Z Tuesday, but have left that out for now since timing and coverage of the next batch of rain is low confidence at this time. && .MARINE... Issued at 324 PM EDT Mon Apr 27 2020 Conditions on the big lake look to be spring like, which is to say fairly tame from Tonight through Tuesday night. Normally this time of year winds and waves are lower due to the fact that the cold water acts as a "bubble high" and does not allow winds to mix to the lake surface. It takes a low pressure system, especially one tugging down cold air from the north to kick up winds and waves. One such system materializes mid week with a low tracking through the Lower Great Lakes from west to east. On Wednesday into Wednesday night northerly winds begin to fill in across Lake Michigan. The latter half of the work weeks looks rough. Gale force winds look likely in a north-northwest flow Wednesday night through at least Thursday. I can see stronger north winds, if not gales, persisting into Thursday night. Gale Watches may be needed for Wednesday night and beyond. Waves of 6 to 10 feet look likely, especially south of Grand Haven. The worst of the erosion given the flow regime will be south of Holland. && .HYDROLOGY... Issued at 324 pM EDT Mon Apr 27 2020 Several wet days are coming up for West Michigan. The good news is that its been fairly dry lately, and our rivers are generally starting things out with some space to give. In fact, many of our rivers have slipped below the long-term average values in the last week or so. Additionally, the trees and vegetation are starting to leaf out and use more water this time of year, so that will help, too. Nevertheless, the soils are not as dry as you might think, and still cant hold as much as they could in some other years. This will lead to increased runoff efficiency into the rivers for any rain that falls over the next few days. General expectations are for 1-2 inches of rain across the area between this evening and Thursday afternoon, with a few areas higher and a few areas lower. The rain will come in multiple waves, spaced out by 12 hours or so, which will actually limit the rises on the rivers. We are expecting most of our rivers to once again rise to near bankfull, but unless our widespread rain totals trend higher than the 2 inch mark, we should avoid significant flooding, especially on the larger rivers. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ UPDATE...Meade SYNOPSIS...Duke DISCUSSION...Duke AVIATION...Meade HYDROLOGY...AMD MARINE...Duke
Area Forecast Discussion
National Weather Service North Platte NE
1057 PM CDT Mon Apr 27 2020 .SYNOPSIS... Issued at 341 PM CDT Mon Apr 27 2020 H5 analysis this morning had a fairly benign pattern across the CONUS. A shortwave trough was located over the Mid- Atlantic with a second strong shortwave noted over northern Minnesota. Another shortwave was located over southwestern Kansas. Further west, a strong shortwave trough was off the coast of British Columbia with weak embedded waves extended from southwestern Oregon into northern Montana. At the surface, a weak surface trough extended from east central Nebraska into south central Nebraska. East of this feature, winds were southerly, while west of this feature, winds were generally from the west or northwest, however, some locations had some variable winds at under 10 MPH. Under clear skies, 2 PM CDT temperatures ranged from 75 degrees at Gordon to 80 degrees at North Platte. && .SHORT TERM...(This evening through Tuesday night) Issued at 341 PM CDT Mon Apr 27 2020 The main forecast challenges over the next 24 to 36 hours is fire weather concerns and the small threat precipitation tonight and again on Tuesday afternoon. For tonight: The shortwave, currently over northern Montana, will approach the western Dakotas around 00z this evening. Increasing mid level warm air advection and steep lapse rates, will lead to increasing chances for showers and possibly a thunderstorm tonight. Forcing remains strongest north of the forecast area with the best chances across the Dakotas. Across northern Nebraska, decided to limit pops to slight chance to low end chance tonight. This forecast was based on the QPF forecast from the HRRR and GFS solns. The GFS and HRRR develop very little precipitation in northern Nebraska tonight. The NAM12 and NAMnest solutions are more favorable, developing more pcpn across northern Nebraska overnight. Feel more confident in the GFS and HRRR solutions, based on their depiction of where the current shortwave trough is upstream in Montana. Lows will be mild tonight due to expected cloud cover with readings in the mid 40s to the lower 50s. On Tuesday, a secondary, stronger shortwave, currently off the coast of British Columbia, will dive southeast from southern Saskatchewan into the eastern Dakotas Tuesday. This system will have a lot of cold air aloft with very steep lapse rates noted Tuesday afternoon. This will lead to an increased threat for isolated showers, especially in the north and northeast Tuesday afternoon. In addition to the threat of isolated showers, strong NW winds will develop on the western and southwestern periphery of the system Tuesday afternoon. Bufkit soundings this morning, indicate high potential for mixing and inverted V type soundings during the afternoon. In some cases, mixing occurs well above 700MB and in some cases, it reaches above 600MB. Winds at these levels is in the 40 to 50 KT range tomorrow afternoon. This equates to gust potential of 40+MPH Tuesday afternoon. The strong winds will lead to critical to near critical fire weather conditions, which is highlighted below in the fire weather section. Highs tomorrow will reach the upper 60s to lower 70s. The latest GFS and NAM12 solns indicate a corridor of high H85 winds from north central into south central and southeastern Nebraska Tuesday evening with winds around 50 KTS noted. This will keep wind speeds elevated through the evening hours. .LONG TERM...(Wednesday through Monday) Issued at 341 PM CDT Mon Apr 27 2020 Winds will shift around to the south from west to east Wednesday afternoon. In the transition, winds will be fairly light across western Nebraska. With minimum RH forecasted to be in the 15 to 20 percent range, the lighter winds will probably alleviate the need for a red flag warning Wednesday. On Thursday, winds will increase from the south as a surface trough of low pressure deepens along the front ranges of Colorado and Wyoming. Minimum RH falls off to 15 to 20 percent Thursday afternoon, and with winds expected to be in the 15 to 25 MPH range Thursday afternoon, we may end up needing some sort of fire headline if forecast trends continue. Friday will be the warmest day of the period with readings touching 90 in the far southwest. Fortunately, winds will be light friday with a surface trough anchored across the forecast area. The pattern aloft will begin to transition more to west southwesterly aloft this weekend and remain in place through Tuesday. This will make for a more active pattern across the area with increased chances for precipitation and thunderstorms. The latest GFS solution is indicating some meager moisture return to the southwestern and western forecast area Sunday with H85 dew points approaching 8-10C. A strong shortwave approaches the central and northern plains Monday into Monday night. With the degree of moisture return, and the strength of this shortwave in the current model solution, this could be the first threat for strong storms this season. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) Issued at 1053 PM CDT Mon Apr 27 2020 VFR conditions expected to persist through the forecast period. A frontal boundary currently moving through the area will bring an abrupt shift in winds to the west-northwest with gusts approaching 25 knots. Sporadic gusts of 40 knots are possible but confidence in occurrence at either terminal is too low to mention at this time. Winds will increase quickly after sunrise on Tuesday with gusts approaching 40 knots for north central Nebraska including the VTN terminal. Elsewhere further south and west, winds will be gusty but limited to around 30 knots or less. As winds subside by late afternoon Tuesday, LLWS is expected to develop and linger through the end of the forecast period. && .FIRE WEATHER... Issued at 341 PM CDT Mon Apr 27 2020 Very strong northwesterly winds of 20 to 30 MPH with frequent gusts to 45 MPH are expected Tuesday afternoon. These winds will be in association with a strong shortwave trough of low pressure, which will slide across the eastern Dakotas into Iowa. Minimum relative humidity tomorrow afternoon will reach 20 to 30 percent across the forecast area. Realize these RH`s are above the threshold for RFW criteria, however, given the strong winds and fuels which are ready to burn (per conservations with fire partners this morning), feel it prudent to hoist a RFW for tomorrow afternoon into the early evening hours for all of the forecast area. Minimum RH will be low each afternoon for Wednesday, Thursday and Friday. Winds will be strongest on Thursday in areas where the RH is closest to RFW criteria, so Thursday afternoon has the best potential for a RFW given the way the forecast stands right now. One final note, RH recovery is only 50 to 65 percent for Wednesday morning and Friday morning. && .LBF WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from noon CDT /11 AM MDT/ to 8 PM CDT /7 PM MDT/ Tuesday for NEZ204-206-208>210-219. && $$ SYNOPSIS...Buttler SHORT TERM...Buttler LONG TERM...Buttler AVIATION...Jurgensen FIRE WEATHER...Buttler
Area Forecast Discussion
National Weather Service Topeka KS
549 PM CDT Mon Apr 27 2020 ...AVIATION UPDATE... .SHORT TERM...(This evening through Tuesday) Issued at 338 PM CDT Mon Apr 27 2020 Weak disturbance that brought a few showers and thunderstorms to the area this morning has slid off to the southeast, leaving clear skies across northeast Kansas this afternoon. With the clear skies and large scale subsidence in place, temperatures have warmed into the mid and upper 70s. Continued southerly winds into tonight and some early morning clouds will keep overnight lows in the mid 50s. Heading into tomorrow, intensifying ridging over the West Coast will cause a shortwave trough initially over Montana to quickly dive southeast into the Plains, eventually carving out a rather deep trough over the central CONUS. This digging shortwave will push a cold front southeast across the region, passing through northeast Kansas in the late morning and afternoon. This timing, along with increasing moisture out ahead of the front, will favor the potential for thunderstorm development during the mid-afternoon, though there is still some uncertainty. The bulk of this uncertainty lies in the possibility of some morning clouds and weak thunderstorms ahead of the front, which may delay the main round of afternoon convection until after the front has moved south of the area. However the majority of short-term models do have enough heating ahead of the front to develop storms by 2-3pm. With steep lapse rates of 7-8 C/km aloft and moderate shear of 35-40 kts, large hail would be possible with any storms. Damaging winds would also be possible given some drier air in the lower levels resulting in higher DCAPE values. Any tornado threat would be non-zero but would be limited by veering winds and quick linear growth along the front. Given the likely frontal position by mid-afternoon, places along and south of I-35 will be most likely to see severe weather, with storms moving south and east of the area by early evening. .LONG TERM...(Tuesday night through Monday) Issued at 338 PM CDT Mon Apr 27 2020 After the initial cold front, a secondary vorticity maximum will drop into the area Tuesday night, driving a secondary cold front southeast again. Moisture will be limited with this, but very favorable dynamics and some weak elevated instability may be enough for a second round of showers and a few rumbles of thunder. Guidance seems to be just starting to pick this up, but have increased PoPs anyways given the favorable dynamics. Wednesday into the start of the weekend, a period of dry and increasingly warm weather will take hold as the strong western US ridge shifts eastwards over the Plains. Temperatures by Friday and Saturday should reach the 80s for most of the forecast area. By the second half of the weekend, more zonal flow will set up across the Plains as moisture gradually increases. With an east/west oriented frontal boundary developing somewhere nearby, and several weak disturbances moving through the zonal upper flow, shower and thunderstorm chances will be present late Saturday into Monday. Exact details are uncertain this far out, dependent on the exact position and timing of various disturbances. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday) Issued at 549 PM CDT Mon Apr 27 2020 Biggest question is whether stratus develops ahead of the front Tuesday morning. The NAM and GFS have been consistent in saturating the boundary layer and the RAP suggests moisture will be to shallow. Given a southerly low level wind has already set up and there isn`t any dry air upstream to advect in, am leaning towards stratus developing. Although confidence is marginal because of the RAP soundings. So will keep CIGS MVFR for now, but there is some potential CIGS could be lower than 1000 feet. Models continue to show the better probs for TSRA development along the front after it has passed the terminals. So will only include a VCTS in the forecast for some possible post frontal showers and storms in the afternoon. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Reese LONG TERM...Reese AVIATION...Wolters