Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/08/17

Area Forecast Discussion
National Weather Service Bismarck ND
933 PM CDT Sat Oct 7 2017 .UPDATE... Issued at 925 PM CDT Sat Oct 7 2017 Did pick up a trace of rainfall here at the Bismarck airport earlier this evening with the very light rain showers across the southwest and south central. The CAMs through the 01 UTC HRRR seem to have a good depiction of this area of light precipitation and will follow their solutions which continue the very light rain chances through around 10 UTC across the James River Valley. UPDATE Issued at 640 PM CDT Sat Oct 7 2017 Little change with this update other than for observed trends through 23 UTC. Isolated showers are possible across the Turtle Mountains for the next 1-2 hours in association with weak impulses along the international border. UPDATE Issued at 440 PM CDT Sat Oct 7 2017 Sustained winds and/or wind gusts not meeting wind advisory criteria, thus will cancel it. Updates to text products coming shortly. UPDATE Issued at 439 PM CDT Sat Oct 7 2017 Sustained winds and/or wind gusts not meeting wind advisory criteria, thus will cancel it. Updates to text products coming shortly. && .SHORT TERM...(This evening through Sunday) Issued at 402 PM CDT Sat Oct 7 2017 A cold frontal passage with an ongoing wind advisory into early this evening is the main highlight of the short term period. Cold front stretched from southern Manitoba into the Turtle Mountains and across central/western ND. Temperatures are in the upper 60s with lower 70s south central. Bismarck VAD wind profile shows 30kt winds between 3kft and 8kft above the ground. BUFKIT soundings show mixing heights to around 8kft south central ND. Wind advisory is marginal but will keep it going this afternoon since a couple sites have manage to achieve criteria, and possible some more before sunset. Latest suite of satellite imagery and surface observations show an elongated 300mb 130kt jet stretched out along the US/Canadian border/north central ND, west to the British Columbia coast. Model/satellite data confirms a couple of jet streaks within the strong corridor of winds aloft. Latest regional radar shows increasing showers in southern Saskatchewan, close to our northern border associated with the nose/left exit region of 130kt jet mentioned above. Other showers were forming in north central MT and moving east with time. Through 06z Sunday, it will be a combination of jet dynamics, multiple mid level shortwaves, and low level instability contributing to upward vertical motion and isolated showers. Low level instability/steep lapse rates will continue through the evening as a cold pocket of air at 850mb, reflection the cold front aloft, begins to push across northwest ND. The 850mb front then slides into south central ND and into the James River Valley by 06z Sunday. With a variety of model solutions on location/timing/longevity of potential showers, have favored an areal coverage mentioning isolated showers across the south versus scattered at this time. The evening shift can monitor for changes and adjust. Cooler Sunday with highs in the 50s and northwest winds 10 to 20 mph. There could be a brief shower or two in the north cental and northwest during the afternoon, along and ahead of a secondary cold front. Current gridded forecast has this in there, dry elsewhere. .LONG TERM...(Sunday night through Saturday) Issued at 402 PM CDT Sat Oct 7 2017 Will likely need a freeze warning west and most of central ND Sunday night/early Monday morning, and all of western and central ND Monday night/early Tuesday morning. Based on current forecast low temperatures early Tuesday morning, some areas will see a hard freeze, while others will not. For a hard freeze, temperatures will have to reach at least 28F or colder for 3 hours or more. Columbus day Monday will be cold. Normal high temperatures are around 60F for western/central ND; expect highs in the mid to upper 40s with northwesterly winds 10 to 15 mph. The weather pattern is active in terms of temperature swings, but not in precipitation potential. A warmup Tuesday and Wednesday with highs getting into the upper 50s Tuesday, then upper 50s/lower 60s Wednesday. A cold front sweeps across western/central ND during the day Thursday with cooler air for Friday and Saturday. Perhaps better chances for precipitation by Saturday. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 925 PM CDT Sat Oct 7 2017 VFR conditions are forecast across western and central North Dakota for the 00 UTC TAF cycle. Very light rain showers are possible across southern North Dakota tonight. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...PA SHORT TERM...KS LONG TERM...KS AVIATION...PA
Area Forecast Discussion
National Weather Service Cleveland OH
934 PM EDT Sat Oct 7 2017 .SYNOPSIS... A cold front will move east across the area tonight. A ridge of high pressure from the mid Atlantic states will extend northwest into the area Sunday. The tropical remnants are expected to move northeast out of the Gulf of Mexico toward the Tennessee Valley region by Sunday night. This feature will bring a swath of more rain to the local area Sunday night into Monday morning. High pressure will build east across the northern Great Lakes from the northern plains states by midweek as yet another low pressure system moves north out of the deep south toward the area. && .NEAR TERM /THROUGH SUNDAY NIGHT/... Minor adjustments to pops with the late evening forecast update, otherwise no major changes. Previous forecast thinking remains largely on track, as thin line of showers and a few rumbles of thunder tracks into NW OH. Upstream wind reports have still been on the low side, with up to 40 kts reported, but mainly in the 35 kt range. Latest hi res model trends point to the initial line spreading northeastward into the area, currently from near Cincinnati up to just south of Toledo. This may become the dominant precip maker, associated with a fairly potent low level jet max surging northeastward. The latest HRRR shows this jet feature increasing to around 75 kts as it moves NE into NW OH and western Lake Erie over the next two hours. Will continue to monitor for the potential of strong convective wind gusts, and an SPS may be needed to handle the threat. Not anticipating any widespread severe gusts at this point, and the weak tornado potential seems to be confined to southwest OH at this point, where the greatest instability and effective SRH max is located. Previous discussion... Focus is shifting to convective potential this evening, as gradient winds have subsided just a bit. Broken line of rather intense showers w/ scattered thunder continuing to track east through Indiana. So far, upstream wind reports are yet to exceed 40kts, although low level jet and moisture return will continue to increase ahead of the line for another couple of hours. It`s becoming diurnally unfavorable for widespread wind damage with the line, but these high shear/low CAPE setups often ignore this convention. Will continue to monitor upstream evolution and still anticipate a low end threat for some strong/severe wind gusts with the line. These setups are also conducive for low end/short lived spin up tornadoes along the leading edge of the storms. So far, no tornado activity has been reported, and radar trends are yet to show an increased threat. Will continue to monitor for this potential with the increasing shear over the next couple of hours. Forecast wise, updated pops to reflect current radar evolution and latest hi-res model trends. Limited thunder mention to chance at this point given upstream lightning trends and the scattered/isolated nature of the lightning activity. Cold front will sweep moisture out of the area Sunday and then another big surge of moisture will lift northeast across the eastern portions of the area as the tropical system moves northeast out of the Gulf of Mexico. QPF amounts in Akron-Canton to Youngstown could approach 1 inch with this surge so that will have to be monitored for heavy rain potential. Temperatures for Sunday will be a few degrees colder today with the cool air mass following the front. Otherwise, overnight lows tonight will still be in the lower to middle 60s in the warm air advection ahead of the front in most areas and then upper 50s in the west behind the cold front. Cool air behind the front lifts northeast of the area Sunday night allowing warmer air to push back into the area. Looking at lows in the lower to middle 60s once again. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... Some of the models continue to track the remnants of Nate farther west and north than the official forecast track. The forecast will follow the NHC/WPC track and Nate should slide off to the east on Monday. Rain will likely linger, mainly in the morning, across northeast OH and northwest PA. Clouds may keep temps suppressed for a while across NE OH and NW PA but the air mass will be warm. Will forecast mid/upper 70s northwest Ohio and upper 60s to mid 70s elsewhere. High pressure will build across the Great Lakes Monday into Tuesday. I suspect the high will be a bit dirty and dew points will remain rather high. Patchy fog and perhaps some stratus could form Monday night and Tuesday morning. Whatever clouds and fog form will likely burn off on Tuesday and thinking that Tuesday will turn out to be a decent day with unseasonably warm temps in the 70s. The models are more in agreement with the timing and track of an upper low ejecting from the southwestern states midweek. The models still have have a variety of solutions on the strength of the surface system. Will not go all out on the rain forecast since the low level flow is down slope east southeast. Will forecast 30-50 percent pops by Wednesday. Even with the clouds and chance of showers, it should remain relatively warm with highs from the mid 60s to the lower 70s. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... Some lingering showers in the East Wednesday night into Thursday morning as Upper level trough begins to shift east of the forecast area. GFS continues to be the faster of the two models with this transition. After that surface high pressure moves across the forecast area. The high shifts off the East Coast Saturday allowing a low pressure system to track into the Great Lakes on Sunday. Still doubts as the the track and timing of the low this far out so will leave weekend forecast dry. && .AVIATION /00Z Sunday THROUGH Thursday/... Showers and thunderstorms are expected ahead of a cold front that will push east through the terminals through the first half of the period. A broken line of TSRA is possible, with some brief periods of MVFR ceilings and visibility, perhaps a brief IFR vis reduction in any stronger showers. Activity will become more scattered east of KCLE and KMFD late in the overnight. After 12Z, little sensible wx concerns with FEW/SCT low clouds and increasing cirrus ahead of the next system from the south. Winds will continue to be strong out of the south, then will veer southwest behind the front through the overnight. Some gusts up to 35-40 kts are possible with the line of showers/frontal passage. Winds will decrease rapidly after daybreak Sunday, with less than 10 kts expected through the day. OUTLOOK...Non-VFR possible Sunday night into Wednesday. && .MARINE... Lots of changes on Lake Erie coming up in a relatively short period of time. South winds will continue to increase this evening. Wind speeds will spike up as a cold front crosses the lake from west to east, roughly from 11 PM (03Z) at Maumee Bay to 5 AM (09Z) at Buffalo Harbor. Winds will shift to southwest with frontal passage and remain enhanced for about 6 hours or so after frontal passage. Winds speeds will approach gale force but the large majority of the wind is expected to stay below gale criteria. A small craft advisory will remain in effect. A low water advisory will be issued for western Lake Erie for the early and mid morning hours Sunday as water levels will drop below the critical mark for navigation during the strong southwest winds. Winds will diminish relatively quickly Sunday late morning and afternoon as high pressure slides across the lower Great Lakes. Water levels will recover rather quickly by late Sunday morning. Winds will back to south and southeast by Sunday night and then shift to the northeast and northwest on Monday as the remnants of Nate cross the Ohio Valley and high pressure builds across the western Great Lakes. Winds will back to the east and southeast by midweek as low pressure tracks across the midwest. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...Low Water Advisory until 10 AM EDT Sunday for LEZ142>144- 162>164. Small Craft Advisory until 4 PM EDT Sunday for LEZ147>149. Small Craft Advisory until 10 AM EDT Sunday for LEZ142>146. && $$ SYNOPSIS...Lombardy NEAR TERM...Greenawalt/Lombardy SHORT TERM...Kosarik LONG TERM...DJB AVIATION...Greenawalt MARINE...Kosarik
Area Forecast Discussion
National Weather Service Green Bay WI
1056 PM CDT Sat Oct 7 2017 Updated aviation portion for 06Z TAF issuance .SHORT TERM...Tonight and Sunday Issued at 234 PM CDT Sat Oct 7 2017 The latest RAP analysis and satellite/radar imagery show low pressure centered over northeast Iowa, with a stationary front extending northeast across north-central Wisconsin early this afternoon. Periods of rain continue to lift north ahead of the low and mid-level dry slot, which is sliding into southwestern WI. A few thunderstorms are also popping up right ahead of the parent shortwave over northeast Iowa, and could see some thunder moving into parts of central WI and the far southern Fox Valley late this afternoon into early this evening. A trailing deformation zone is rotating around the shortwave from far western WI to central Iowa, which is expected to arrive this evening. As the low moves to the northeast, precip trends is the main forecast concern. Tonight...Potent shortwave trough and associated cold front will sweep across the area this evening before exiting around midnight. Showers will be most widespread early this evening ahead of the shortwave. A rain band within a skinny deformation zone will then lift northeast across the area around mid to late evening, and depart NE WI around 05z. Models insist on clearing skies relatively quickly thereafter. Because of a tight pressure gradient, winds look too mixy for a fog threat despite the heavy rainfall. Temps falling into the mid 40s north to mid 50s south. Sunday...Other than a moisture starved trough providing scattered clouds over central and north-central WI, the rest of the area should see mostly sunny skies with a breezy south wind. Temps will be well above normal, with highs in the upper 60s to middle 70s. .LONG TERM...Sunday Night Through Saturday Issued at 234 PM CDT Sat Oct 7 2017 The main forecast concerns will be frost potential across northern WI Monday night, then precipitation chances for the middle of the week and next weekend. A weak cold front will move through the region on Sunday night, but little or no precipitation is anticipated due to a lack of upper level forcing. High pressure will build into the northern Great Lakes in the wake of the front, and linger over the region through Tuesday. There is some potential for a frost/freeze event over mainly northern WI Monday night/early Tuesday, but there are concerns about whether or not clouds will decrease early enough for a widespread event. For now, just lowered temperatures a few degrees in the typical cold spots and added patchy/areas of frost in north central and far northeast WI between 09z-14z/Tues. An upper level trof and associated surface low will impact the region Tuesday night into Wednesday. Th ECMWF is stronger and farther north, and would bring a steady light to moderate rain to most of the forecast area, while the GFS is weaker and farther south, and just brings scattered showers to our southeast counties. Will stick with the model blend for now and make adjustments over upcoming days. A fairly potent frontal system is possible next Friday night and Saturday. Models show an 850 mb warm front lifting north through the region, with a strong low-level jet developing on Saturday. In addition, the RRQ of a 150 knot jet would provide upper support. Elevated instability is expected to arrive on Saturday, so added a mention of thunder in the forecast. A cooling trend is expected early next week with mainly northerly surface flow, but moderating temperatures should return later in the week. && .AVIATION...for 06Z TAF Issuance Issued at 1056 PM CDT Sat Oct 7 2017 Isolated showers and MVFR cigs will shift eastward overnight as a low pressure system lifts northeastward and a cold front tracks east of the state. MVFR cigs will improve to VFR levels, however clearing skies and light winds with the recent rainfall may lead to areas of mvfr/ifr fog later tonight. VFR conditions are then expected for Sunday. && .MARINE... Issued at 234 PM CDT Sat Oct 7 2017 Gale force gusts have yet to materialize over the central Bay and northern Lake Michigan so far today. With winds expected to gradually decrease for the rest of the afternoon, will downgrade the gale warning to a small craft advisory. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......Kieckbusch AVIATION.......TDH MARINE.........MPC
Area Forecast Discussion
National Weather Service Indianapolis IN
1139 PM EDT Sat Oct 7 2017 .UPDATE... The Aviation section has been updated below. && .SYNOPSIS... Issued at 1236 PM EDT Sat Oct 7 2017 A cold front will sweep across Central Indiana this evening...bringing showers and isolated thunderstorms to the area. Dry weather will briefly resume late tonight as the front departs overnight and on Sunday morning. However by Sunday afternoon and Sunday night...moisture associated with Hurricane Nate will begin to surge into the Ohio Valley. This will result in rain chances returning to mainly southeast parts of Central Indiana late Sunday afternoon and Sunday night. As the hurricane Remnants depart on Monday...Dry weather will once again return as High pressure strengthens over the upper midwest and provides dry northerly flow to Indiana. Rain chances will then return on Tuesday night and Wednesday as a warm front approaches and an associated Low pressure system pushes toward the Tennessee River Valley. && .NEAR TERM /Tonight/... Issued at 650 PM EDT Sat Oct 7 2017 Minor adjustments to pops to better reflect current radar trends. Expect line of heavy rain and a few rumbles of thunder to sweep across the forecast area in the next couple of hours and depart relatively quickly. Threat remains for isolated damaging wind gusts and perhaps even a quick spinup. All areas will likely see at least a period of heavy rainfall and quick wind gusts to 40-45 MPH with the line. Previous discussion follows. Issued at 1236 PM EDT Sat Oct 7 2017 Surface analysis early this afternoon shows a cold front stretching pushing toward eastern Missouri. The front was associated with Low pressure which was found over Iowa and Wisconsin. GOES16 shows a cloud shield ahead of the front across Illinois and Missouri. Radar shows an area of showers over Western Illinois. HRRR continues to suggest the eastward progression of the cold front and associate showers tonight...reaching the Illinois/Indiana state line near 23Z before progressing across the state through 04Z. Time Heights how good lower level moisture and strong lift as this front is expected to pass. Forecast soundings also show limited instability with marginal CAPE of around 400 J/KG...but some good moisture within the lower levels. Convective temps are suggested to be in the upper 70s. Thus some limited shallow development is expected late this afternoon ahead of the front. Will try and raise pops late this afternoon and early evening with the expected FROPA. Given the strong drying and subsidence that is seen within the wake of the front....will quickly trend toward a dry forecast after 06Z...sticking close to the blend on Temps. && .SHORT TERM /Sunday through Tuesday/... Issued at 1236 PM EDT Sat Oct 7 2017 Large High pressure aloft off the Carolina coast will continue to allow for a warm and moist flow of gulf air into the Ohio Valley. The remnants of Hurricane Nate look to follow this path through the deep south late tonight and into the Ohio and Tennessee valleys on Sunday. Models suggest excellent moisture arriving across southeast parts of the forecast area...while a sharp cut- off will exist to the northwest. Forecast soundings across IND fail to show deep saturation...but much better saturation appears present to the southeast. Thus given this path...will trend highs pops on Saturday afternoon and evening...mainly across the southeast parts of the forecast area with a sharp decrease in pops to the northwest. Again will use a blend on Temps. By Monday morning...the GFS suggests that remnants of Nate will have reached West Virginia and will be quickly moving northeast. Meanwhile strong ridging begins to settle across the Western Great Lakes...allowing for Northerly flow to central Indiana. Forecast soundings respond with a very dry column...and convective temperatures that appear reachable. Aloft...southwest flow remains prevalent on Monday and a deeper upper low begins to push in to the western plains states. Little in the way of dynamics appear to surge ahead of the low...which should help to keep Indiana dry on Monday and Tuesday. The quick albeit moist flow aloft may result in mainly just some High cloud. Forecast builder may try into introduce some pops on late Tuesday as the GFS hints at a warm front approaching from the southwest ahead of Low pressure...but for now...this looks more likely to arrive on Tuesday Night and Wednesday. && .LONG TERM /Tuesday night through Saturday/... Issued at 207 PM EDT Sat Oct 7 2017 The long term period will begin with an active weather pattern in place as an upper wave and associated surface front move through central Indiana. This will keep chances for showers in the forecast through Wednesday. By Wednesday night though models agree that upper ridging will start to build over the area. Thus after cooling to near normal for Wednesday and Thursday in the wake of a cold frontal passage, warming will return Friday under building surface high pressure. && .AVIATION /Discussion for the 08/06Z TAFs/... Issued at 1140 PM EDT Sat Oct 7 2017 VFR initially may give way to MVFR for a time near daybreak. With skies clearing and wet ground, expect some fog to develop near daybreak. Will carry 2 miles at the outlying sites and 3 miles at IND, with a BCFG mention as patchy dense cannot be ruled out. Will have to monitor this overnight as winds die down. Winds will generally be below 10KT throughout the period, westerly early and occasionally variable later in the period, before becoming more easterly. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...Puma NEAR TERM...Puma/Nield SHORT TERM...Puma LONG TERM...CP AVIATION...Nield
Area Forecast Discussion
National Weather Service Jacksonville FL
858 PM EDT Sat Oct 7 2017 .UPDATE... The convection near and west of I-75 is actually some sea breeze convergence but has become somewhat entrained in the very, very, very outer periphery of Nate`s circulation. Thus it has just a little bit more than normal diurnal heating support and will go on until midnight or 1 a.m. After that will see some mid deck and the high cirrus/cirrostratus outflow from the tropical system overnight. Also will see a weak southeasterly flow around the system keeping winds in the 4 to 8 mph range. Both of those factors should serve to limit fog formation but still might see some light mist near sunrise at the usual places such as Cecil Airport and Gainesville. && .AVIATION... Convection is moving past Gainesville Regional Airport now and the band of convection is expected to fall apart before it can reach the Jacksonville Metro fields. Might see some light mist near Gainesville and Cecil Airport Sunday morning and will keep in the 5-6sm range. Should see some convection tomorrow afternoon as Nate passes to our north and west and outer rainbands trail across the region. Will go with cloud bases at 5 KFT for now but later shifts may have to lower bases is more tropical based convection becomes evident. Convection should begin between 17-19 utc based on the NAm12 and HRRR solutions. && .MARINE...SCEC for seas will remain intact for the offshore waters for tonight. SCEC will likely be needed on Sunday due to stronger southerly flow near 15-20 kt. Seas may continue to be dominates by swells of about 9-10 seconds. An extended period of onshore flow will continue Mon with winds near 10-15 kt or less...with lighter winds by mid week. Rip Currents: Moderate risk of life threatening rip currents on Sunday as the southeasterly flow increases. && .HYDROLOGY/COASTAL FLOODING...Minor to moderate coastal flooding anticipated in the St. Johns River Basin into Monday Morning. Water levels about 1.5 to near 2 ft above astronomical predictions with moderate flooding occurring near the time of high tide. This is a combination of Fresh water flooding on top of the normal river brackish layer and the "King Tides" peaking on Monday and Tuesday. Trends continue to show a downward trend in water levels. Sante Fe River basin remains in minor flood. && .PRELIMINARY POINT TEMPS/POPS... AMG 90 76 86 75 / 30 30 80 30 SSI 83 77 85 77 / 20 20 50 20 JAX 90 77 88 75 / 20 20 60 30 SGJ 86 77 88 75 / 20 20 40 20 GNV 89 76 88 73 / 50 40 70 30 OCF 89 76 89 73 / 60 50 80 30 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...Coastal Flood Warning until 6 AM EDT Monday for Clay-Coastal Duval-Flagler-Inland Duval-Putnam-St. Johns. GA...None. AM...None. && $$ Hess/Sandrik/Corless
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
621 PM CDT Sat Oct 7 2017 .SYNOPSIS... Issued at 325 PM CDT Sat Oct 7 2017 H5 analysis from earlier this morning had a strong trough of low pressure centered over central Kansas. Ht falls in association with this feature, were most pronounced across southern Kansas into western Missouri. Downstream of this feature, high pressure was anchored off the coast of the Carolinas with a ridge extending north into Quebec. West of the central CONUS trough, a low amplitude ridge was present from California north into southern Idaho. A trough was present north of the ridge across the Canadian prairie provinces with some 150 to 200 meter ht falls noted over Saskatchewan into western Manitoba. At the surface, low pressure was anchored over central Iowa with a cold front extending south into the Ozarks. West of this feature, clearing skies and westerly winds were present across western and north central Nebraska. Readings as of 1 PM CDT ranged from 65 at O`Neill to 75 at Valentine. && .SHORT TERM...(This evening through Sunday) Issued at 325 PM CDT Sat Oct 7 2017 This evening and tonight... Available moisture remains minimal ahead of the cold front approaching the panhandle. Dew point depressions range from 25F at KONL to 35F at KIML as of 20z and PWATs under 0.5 inch according to RAP mesoanalysis. Models are consistent with overall subsidence and isentropic downglide through 12z Sunday, and little cloudiness is shown upstream in WV/IR imagery, suggesting a generally clear night for western Neb. Made little change to min temps, keeping upper 30s far NW and lower/mid 40s elsewhere, which is above guidance. An H85 thermal ridge with temps as warm as 20C crosses the forecast area overnight. Along with a 30+ kt LLJ, some of which may translate to the sfc, winds should stay somewhat elevated and limit decoupling/cooling. Sunday... The cold front should be east of the forecast area by 12z and with continued limited moisture, expecting a dry fropa. CAA is well underway at 18z with H85 temps falling back below 10C. Forcing and moisture advection strengthen during the afternoon as a lee side low develops in SE CO/SW KS and a shortwave exits CO/WY. Saturation will be rather slow across the area and have held off PoP for all areas except NW Sheridan Co. after 21z. Went with general blend for max temps, averaging the warmer MET and MAV with the cooler ECS, resulting in upper 50s NW to near 70 far SW. .LONG TERM...(Sunday night through Saturday) Issued at 325 PM CDT Sat Oct 7 2017 Sunday night through Tuesday: Precipitation chances Sunday night/Monday followed by the potential for freezing conditions Tuesday morning are the main forecast concerns in the mid range. Beginning Sunday night, a potent H5 shortwave will dive south into northern Utah. As this feature tracks southeast into western Colorado overnight, mid level frontogenesis will increase from southern Wyoming into the Nebraska Panhandle and northwestern Nebraska. Cross sections taken from south central into northwestern Nebraska indicate a nice area of mid level lift across the western and northwestern sandhills overnight, with plenty of mid to low level moisture present. This lift resides in the saturated dendritic zone, so favorable conditions exist for snowfall in the nwrn cwa overnight. One thing which will limit accumulations though is the very warm ground temps and temps in the 33 to 35 degree range. The latest soil temps from UNL Crop Watch indicate soil temps in the northwestern CWA well into the upper 50s. The warm ground temps will limit snow accums during the night and combination of sun and warm ground temps will almost eliminate any threat for snow accums during the daylight hours Monday. That being said, will limit snow accums to the northwestern forecast area Sunday night and keep them on the order of an inch or less which is in agreement with the latest WPC depiction. For Monday, the GFS and NAM12 solns, drop the H5 low into southern Colorado. Favorable mid level frontogenesis will transition south into swrn Nebraska, as well as central portions of the forecast area, before shifting east Monday night. As the mid level fronto band shifts south, any threat for snow will end by mid morning due to a combination of temps in the upper 30s/lower 40s and warm ground conditions. By Monday evening, there are some differences between the GFS and NAM12 solution with respect to the H5 low. The NAM12 soln closes the low off over southern Kansas Monday night while the GFS lifts this feature east across Kansas as an open wave. The more progressive GFS soln would equate to drier conds Monday night, while the slower NAM12 soln would allow pcpn to linger in the east Monday night. The inherited forecast does linger pops in the eastern CWA Monday night and will leave as is for now. Further west, dry air will filter in behind the exiting system with dew points falling off into the teens and lower 20s. The combination of dry air, high pressure and a cold airmass behind the front, will lead to widespread lows in the 20s with readings around 30 in the east. Inherited forecast has widespread frost across the forecast area and will probably need to issue a freeze warning for most of the forecast area sometime Sunday night or Monday, for Monday night. Will continue to hit this in the HWO. Tuesday night through Saturday: In the wake of the exiting system early next week, a low amplitude ridge will push into the northern Rockies and northern plains midweek. Warmer air will push into the central plains from the swrn CONUS which will push highs back into 60s Wednesday through Friday. Late Thursday, a shortwave trough of low pressure will traverse southern Canada, forcing a weak cold front into the region Thursday night. Its impacts will be greatest on the northern and northwestern forecast area, where highs will be around 60 for Friday. On Saturday, a second, deeper trough of low pressure will track from the nwrn CONUS into northern California. This will amplify a downstream ridge across the Ohio valley and southern plains. Further north, swrly flow aloft will become anchored across the central plains. This will lead to warmer temps and a threat for showers and thunderstorms across southern and eastern Nebraska. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 621 PM CDT Sat Oct 7 2017 VFR is expected all areas overnight and Sunday. A Pacific cold front, currently across MT, will move through overnight. No significant low level cloudiness is indicated in any of the models. Scattered midlevel clouds will prevail. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Buttler SHORT TERM...Snively LONG TERM...Buttler AVIATION...CDC
Area Forecast Discussion
National Weather Service Marquette MI
700 PM EDT Sat Oct 7 2017 .SHORT TERM...(This evening through Sunday) Issued at 410 PM EDT SAT OCT 7 2017 WV imagery and RAP analysis indicated a vigorous mid/upper level shortwave trough lifting northeast into srn WI. At the surface, an elongated 993 mb low extended from wrn Upper Michigan into se MN resulting breezy southwest winds over the east half of the cwa with gusts to 30 knots at KERY. Although the larger area of heavy rain supported by the stronger upper level div from the the jet right entrance and 850-600 fgen has lifted to the northeast of the cwa, a trailing band of 850-600 mb deformation/fgen and narrow band of shra was aligning/moving toward central Upper Michigan. Tonight, short range models suggest the narrow band of heavier pcpn will affect areas of w cntrl Upper Michigan mainly west of Marquette into the early evening before sliding to the east btwn 00z-03z. However, some sct -shra will still linger over the rest of the cwa. By late evening and overnight the pcpn will quickly exit to the east and end with clearing quickly spreading over the area. Sunday, Sunshine and mixing with 900 mb temps around 15C will support max readings into the lower 70s, especially where downslope wsw flow prevails. .LONG TERM...(Sunday night through Saturday) Issued at 308 PM EDT SAT OCT 7 2017 Overall, the weather looks to remain rather quiet next week, with periodic chances for showers towards the end of the week/early next weekend. Temperatures will fluctuate through the week as we start off seasonal and then warm up into the low to mid 60s by the middle of the week, and then back to more seasonal early next weekend. Monday through Tuesday, the weather is expected to remain quiet as high pressure drops down from Canada. There is an upper-level trough progged to move across the Upper Great Lakes; however, with a much drier airmass advecting across the area do not expect any precipitation to reach the ground. Wednesday through Friday, surface ridging will move east of the area with high pressure reaching the East Coast by Thursday/Friday. This will allow return flow developing across the Central and Upper Mississippi Valleys to move across Upper Michigan ahead of approaching longwave troughing over the western CONUS. 850mb temperatures will warm to near or around 10C towards the end of the week as a result, allowing for the return of above normal temperatures. This return of warmer air and increasing moisture will also allow for periodic chances for showers later in the week as a weakening cold front tracks across the area. Medium range models show a lead shortwave ejecting out of the aforementioned longwave troughing across the Upper Mississippi Valley, with the main surface low remaining well north of the area in Canada. With the better lift tracking north of Upper Michigan do not expect widespread precipitation associated with the frontal passage at this time. Next weekend, as the above mentioned longwave troughing slowly continues to traverse the Rockies and moves out across the Plains, the medium range models diverge in the strength of this trough. Therefore, confidence is not high in regards to how precipitation chances will play out as the track and timing of the system associated with this upper-level energy remains rather variable. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 700 PM EDT SAT OCT 7 2017 Conditions will improve quickly at all sites tonight as the showers moves out. Improvement to VFR should occur at KIWD/KCMX this evening and at KSAW by 06z. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 410 PM EDT SAT OCT 7 2017 Broad sfc low will track ne across the e half of Lake Superior this evening with gusty ssw winds to near 30 knots over the far ern portion of the lake. Winds will be much lighter to the w of the low track over western Lake Superior. As the low departs tonight, w to sw winds of 20-30kt will develop across most of the lake. Winds will diminish on Sun, and winds should be mostly less than 20kt Sunday night thru Thu. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... Gale Warning until 8 PM EDT this evening for LMZ221-248-250. && $$ SHORT TERM...JLB LONG TERM...Ritzman AVIATION...07 MARINE...JLB