Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/31/17

Area Forecast Discussion
National Weather Service Grand Forks ND
944 PM CST Mon Jan 30 2017 .UPDATE... Issued at 942 PM CST Mon Jan 30 2017 Slight adjustments made to temps...which are warm in the valley...and changed flurries/light snow/drizzle wording to coverage from probability as MRMS imagery showing several waves of light precip moving across the area tonight. Not seeing much in the way of ground truth west of Fosston but could easily see patchy drizzle or flurries behind this, depending on ice in clouds aloft, which soundings show as borderline this evening. UPDATE Issued at 700 PM CST Mon Jan 30 2017 Will make slight adjustments to POPs and wx type for remainder of evening...with HRRR guidance for the POPs. Highest returns off radar have now cleared most of the valley with exception of Fargo and will keep likely wording in through the evening hours...per HRRR guidance which has a good handle on radar trends. ForecastBuilder tool did introduce some light freezing rain across the northern valley however returns in this area are very light so not expecting any significant impacts should any rain/drizzle fall. Mostly snow in the higher returns north of Hwy 200 with a possible mix further south from Fargo through Park Rapids. && .SHORT TERM...(This evening through Tuesday) Issued at 323 PM CST Mon Jan 30 2017 Forecast challenges will be light snow chances tonight and into Tuesday. Went ahead and cancelled our winter weather headlines and trimmed the wind advisory to just SE ND ending at 7pm. Wraparound snow was less robust than expected and wind potential across the DVL BSN decreased with the more western track of the SFC low. As the 500mb weak trough continues to swing to the south out of Canada it will interact with favorable exit region of 300mb jet allowing for episodes of light snow to traverse the northern plains tonight into Tuesday. Temperatures rather steady overnight with cloud cover holding values up. Slightly cooler for max temps with upper 20s to near 30 expected as the blyr temperatures cool only slightly. .LONG TERM...(Tuesday night through Monday) Issued at 323 PM CST Mon Jan 30 2017 The main story to start the period will be the return of colder air as surface high pressure begins building into western portions of the region by midweek. 850 mb temperatures dropping back down into the -18 to -20 C range will push temperatures into the more normal range, or even slightly below. Otherwise, quiet conditions look to prevail through the end of the work week as the surface high moves through maybe even bringing a little sunshine for a few days. As the surface high shifts to the south and east, return flow will set up for the weekend with 850 mb temperatures rising slightly. A decent upper wave is progged to pass through the area in the Saturday-early Sunday time frame which could bring another chance for accumulating snow. However, plenty of model differences remain at this time as the ECMWF is faster and weaker with this feature while the GFS is slower and much more bullish in regards to QPF. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 700 PM CST Mon Jan 30 2017 Mostly MVFR cigs tonight across the area however may see some breaks in the clouds along and north of Hwy 2 corridor. Vsbys will fluctuate at FAR/TVF/BJI as rain or snow moves through the aerodromes. Cigs should improve across eastern North Dakota tomorrow afternoon. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Speicher SHORT TERM...JK LONG TERM...Lee AVIATION...Speicher
Area Forecast Discussion
National Weather Service Sioux Falls SD
916 PM CST Mon Jan 30 2017 .UPDATE... Issued at 915 PM CST Mon Jan 30 2017 Wind speeds continue to subside as anticipated through the evening. As of 9 pm, gusts even across the higher elevations in southwest Minnesota have dropped off well below advisory criteria, and have cancelled remaining portions of the advisory. UPDATE Issued at 603 PM CST Mon Jan 30 2017 Loss of heating has allowed mixing to diminish early this evening, resulting in wind speeds dropping below advisory criteria over much of the area. Exception is across southwest Minnesota and portions of our northwest Iowa counties, where speeds are remaining close to or just above criteria. Thus have decided to cancel the wind advisory from our South Dakota/Nebraska/western tier of Iowa counties. May be able to cancel other portions early as well, and will continue to evaluate through the evening. && .SHORT TERM...(This evening through Tuesday) Issued at 350 PM CST Mon Jan 30 2017 Winds continue to howl this afternoon behind a fast moving clipper system entering into the western Great Lakes. In general, not quite maximizing the full areal potential for this event, especially over deeper snow pack areas where mixing just hasn`t been quite sufficient. A strong pressure gradient has been responsible for the majority of the sustained winds today. That said, areas where the snow depth is an inch or less have been able to push the 40+ knot mark, very well indicated in HRRR guidance. Tonight: Will leave the wind advisory in place, although once sunset arrives, we may quickly lose the rather strong gusts. Winds along the Buffalo Ridge and other higher elevation locations may remain near advisory levels through the evening hours. Soundings show some potential cold advection aloft arriving prior to daybreak Tuesday which may keep us rather breezy through Tuesday morning. Could even see some 30-35 knot downward momentum transfer prior to daybreak. Tuesday: Low level clouds may brush the northeastern third of CWA, before dipping into the CWA later in the afternoon, with increasing mid-level clouds in the Missouri River valley by the mid-afternoon hours. We could see a few sprinkles or flurries in the far southwestern CWA after 4pm, and northeastern CWA by mid-day. .LONG TERM...(Tuesday night through Monday) Issued at 350 PM CST Mon Jan 30 2017 Mid-level frontal band will linger early in the evening near the Missouri River, and likely the only small threat for any very light measurable light snow will brush the Lower Brule areas during the early evening. Otherwise, cyclonic flow surrounding the Great Lakes and back into the plains will feature another weak impulse cycling through overnight on Tuesday. With this feature will progress a backdoor convergence boundary behind which a little stronger cooling will begin to settle in across the area. Temps near this zone become more favorable for ice processes, and would expect that the shallow moisture profiles would begin to suggest potential for a few flurries by later night into east central SD and southwest MN, which will settle through southwest MN and into the northern portions of northwest IA early Wednesday morning. Through Thursday, plenty of clouds will remain near/south of I-90 with mid-level confluence zone, with some partial clearing edging in from the north. Continued cold advection should help to keep mixing enhanced, but overall easing of the off-surface gradient should limit northwest winds to 15 to 25 mph at strongest. Residual snowcover will impact temps somewhat, but only mixing from upper teens to lower 20s north of I-90, mid 20s south. A few upper 20s hold on for Wednesday in the lower Missouri valley. Flow flattens a bit Thursday night into early Friday with wave in the northern stream working through the confluent zone. Tight mid- level frontal boundary in place. Main PV advection favored a bit more northward from I-90, but better lower to mid-level front and moisture poised a bit to the south. Strong frontogenetic forcing with lift positioned well in the ice growth region, and have boosted pops well over initial blend toward the Missouri corridor, with drying from low-level ridge limiting the northward push. Could be a nice 1-2 inch band. ECMWF a bit quicker and bit further south with frontal boundary, and will have to see if deeper dynamic support tries to entice a bit more north as time approaches. Clouds will try to thin again from the north behind wave through the day on Friday, and with large area of high pressure in place, any new snowcover could yield some fairly cold lows, at least closer to or somewhat below normal, with 925 hPa temps in the -8 to -12C range. Another wave is forecast to make a move into the plains later Friday night and pass over the area on Saturday, but origins of this wave come from the southern branch. Increasing warm advection ahead of wave will yield a developing area of precipitation, with snowfall becoming more widespread as it builds east through the morning and early afternoon. While mainly a light event, both ensemble and operational QPF bring into play another 1 to 3 inch event, especially for areas toward I-29 and eastward. Surface gradient gets fairly brisk on Saturday, but from a milder southerly direction, with readings expected to bounce back into the mid 20s to lower 30s. End of the longer range period trends toward more uncertain, with GFS and ensembles largely retaining more northwest flow through the northern plains compared to flatter ECMWF. GFS drives another reinforcing arctic surge southward with a light snowfall threat later Sunday night/Monday, while ECMWF loads up cold air to the north through Monday, with potential for a bit more significant system just outside the forecast period. For now, confidence in any particular solution type is low and have stayed pretty close to home with the initial blend. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 523 PM CST Mon Jan 30 2017 Frequent northwesterly wind gusts at or above 25kt this evening should diminish some through the overnight hours, though could be more persistent in higher elevations of southwest Minnesota. After a relative lull in wind speeds late tonight/early Tuesday, will see increase in gusts again after 16z Tuesday. However, speeds expected to be less than Monday, gusting 20-25kt for most areas through Tuesday afternoon. MVFR ceilings will prevail across northeast portions of the forecast area, primarily along and northeast of a De Smet to Luverne to Spencer IA line. Stratus will be close to KFSD, and could see a broken MVFR ceiling at KFSD for a few hours overnight before the stratus retreats back to the northeast. VFR conditions will prevail through the western and southern portions of the area, including KHON/KFSD. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ UPDATE...JH SHORT TERM...Dux LONG TERM...Chapman AVIATION...JH
Area Forecast Discussion
National Weather Service Green Bay WI
931 PM CST Mon Jan 30 2017 Updated aviation portion for 06Z TAF issuance and new information added to update section .UPDATE... Issued at 930 PM CST Mon Jan 30 2017 Have finally settled on a plan for headlines for the rest of the night. Precipitation tapered off to periods of light snow and freezing drizzle early in the evening as the mid-level dry slot overspread the area in the wake of the main snow band. Deeper moisture is now shifting back into the area from the northwest, so the freezing drizzle threat will end from northwest to southeast as the precipitation changes back to all snow. Although freezing drizzle may not be completely done by 04Z in central Wisconsin, it should end soon enough thereafter to be able to allow that portion of the WW.Y to expire as scheduled at 04Z. The situation in the east is somewhat muddled. The inverted trough that is forecast to develop over eastern Wisconsin seems to be materializing. Added convergence near that feature will probably lead to another period of steadier snow in the east, though the timing of that will probably be 09Z-18Z, or basically right after the current advisory expires. It seems likely that some locations in the east will get another 1-3 inches from that feature. Given the potential for freezing drizzle for a few more hours, and a recent uptick in radar returns dropping into east- central Wisconsin from the northwest, will leave the eastern portion of the WW.Y intact. That will allow the midnight shift to easily extend it if it appears the snows will be heavy enough to affect the morning commute. Will send updated WSW around 945 pm to cover the expiration of the advisory in central WI, but updated coding is already shown at the end of this AFD. UPDATE Issued at 848 PM CST Mon Jan 30 2017 Continue to receive some reports and indications on METARs of FZDZ within the dry slot. Any lingering FZDZ should end from NW-SE as mid-level moisture drops back SE into the area behind the departing system. Will make a few headline adjustments. Will drop Oneida and Lincoln. Plan to keep the rest of the central WI grouping going through to scheduled expiration at 04Z due to the FZDZ. Will move Waushara to the eastern grouping (10Z expiration) to better match MKX. Waushara will also have the potential for FZDZ a little longer than the rest of central WI. Updated product suite will be out ASAP. UPDATE Issued at 645 PM CST Mon Jan 30 2017 The primary band of heavy snow weakened considerably and was shifting east of the area. Periods of light snow linger in it`s wake, along with a few heavier snow showers. The ASOS at AUW also recently reported FZDZ, and an estimated sounding for that area suggests temperatures in lingering low-level moisture may not be quite cold enough to ensure ice crystals are present now that mid- level dry slot has pushed into that area. Expect moisture to deepen again later this evening, but added some FZDZ to the southern part of the forecast area for a few hours as mid-level dry slot passes through. The FZDZ isn`t likely to be a big deal as it will be falling on fresh snow anyway. The main forecast issue now centers on how to handle the rest of the evening and overnight period. A lull in the snow is likely for several hours this evening, then it will probably pick up some again as deeper moisture in remnants of comma head/upper deformation zone swing back through the area. Low-level forcing in increasingly convergent flow over eastern Wiscosnin will probably also help in generating more snow in the east. The problem is the timing of the advisory. The lull across the western part of the forecast area will probably last through the remainder of the advisory (which expires there at 04Z). Given the snow reports we/ve received from central Wisconsin and the speed with which it fell, prefer to hold onto the advisory a little longer. Will take another look in an hour or so. The increased snow in east-central Wisconsin also looks like it may not really get going until later tonight and then go past the end of the advisory into tomorrow morning. Always nervous about what will happen with these small scale snow bands, especially since there could be a lake contribution. But present forecast does not really have snow totals that justify extending the advisory. Will leave it run for now, and re-evaluate once the 00Z dataset begins to arrive. UPDATE Issued at 445 PM CST Mon Jan 30 2017 A compact, intense mid-level shortwave was driving east-southeast across southwest Wisconsin late this afternoon. The feature was very impressive on water-vapor satellite imagery. Given steepening mid-level lapse rates just to the southwest of the area and convective look to cloud elements on satellite, would not be surprised if a few lightning strikes show up on the LDS in the next couple hours. The lead band of snow was initially very narrow, but within the past hour or so there has been an increasing tendency for convective elements to develop and merge into the southwest side of the band. This has effectively widened the snow band and delayed it`s departure from central Wisconsin. With the strongest QG forcing how shifting across south-central Wisconsin, this will probably continue into eastern Wisconsin for another hour or two. Snowfall totals in current forecast seem on target. It`s quite possible that some locations will end up exceeding 6 inches, but that will in part be some of the snow that occurs after an expected lull during the mid-evening. So do not plan any upgrades to a warning as of now. The one upgrade may be needed is to add Door to the advisory. Will be watching closely during the next hour to see just how strong the band remains as it shifts farther into the county. && .SHORT TERM...Tonight and Tuesday Issued at 210 PM CST Mon Jan 30 2017 The latest rap analysis and satellite/radar imagery show a strong clipper system diving southeast over central Minnesota early this afternoon. Warm advection snows have pushed into central WI ahead of this system in a narrow/focused band with visibilities falling to a 1/2 mile at Marshfield and Wisconsin rapids. Could see a quick 2 to 4 inches over central WI this afternoon within this band. It should then move into the Fox Valley by around 20-21z and drop 1-3 inches by the end of the afternoon. A wider area of snow resides across far northwest Wisconsin and northeast Minnesota with a tight deformation area of the clipper, which should pass across the area late this afternoon into this evening. Needless to say, the evening commute will likely be a slow/messy one across the area. Snow trends and amounts are the main forecast concerns. Tonight...Rather impressive clipper system will drop southeast from west-central WI to southeast WI. North of the low track, narrow but potent mid-level fgen band will produce moderate to heavy snow over central to east-central WI this evening. Additional accums look to reach 1 to 3 inches in the evening, highest in east-central WI. Some lake enhancement is possible over northeast WI as low level winds back from the south to the southeast, but mesomodels (except for the arw) are not really picking up on this potential so didnt want to go all in. However, they are picking up on an inverted trough that is expected to develop over northeast WI overnight from the east- central WI lake shore to Iron Mountain which could also enhance snowfall. So increased qpf/snow amounts slightly in this area, which leaves northern Oconto, the Door and Marinette Counties right on the edge. Will let the system play out more before adding more counties to the advisory. In general though, snow will be ending from northwest to southeast from mid-evening through the overnight. Amounts in the advisory remain on track in the 3 to 5 inch range, though could see isolated 6 inch amounts where the rather intense snow bands are more persistent. Tuesday...As low pressure moves southeast and away from the region, the inverted trough (and more focused snowfall) should dissipate over northeast Wisconsin early in the morning. But northern Wisconsin will remain on the cyclonic side of the upper jet, with model cross-sections showing ample moisture in the column through the day. In addition, lapse rates are anticipated to steepen through the day with mid-level lapse rates reaching up to 7.5 C/km in the afternoon. So think will see snow showers/flurries pick up in intensity in the afternoon, after a relative lull in the morning. Cannot rule out accumulations up to an inch or inch and a half in some places, if yesterday was an indication. Warmer temps in the mid 20s to lower 30s. .LONG TERM...Tuesday Night Through Monday Issued at 210 PM CST Mon Jan 30 2017 Cooling air mass with s marginal moist boundary layer combined with cold air aloft, 500 mb height temps of -35 C or colder, creating unstable mid level lapse rates Tuesday night into Wednesday. As a result, potential of snow showers and flurries lingering into Tuesday night and perhaps part of eastern Wisconsin early Wednesday until surface dewpoints fall into the single digits. The cold air aloft will also lead to lake effect snows over far north central Wisconsin but the direction does not appear favorable for significant accumulation through Wednesday at this time. Colder dry conditions expected for the rest of the week into Friday night. Medium range models are focusing the next chance of snow toward Saturday afternoon into Sunday as return flow, ahead of a developing low pressure area and upper trough tracks over the western Great Lakes region. && .AVIATION...for 06Z TAF Issuance Issued at 930 PM CST Mon Jan 30 2017 Poor flight conditions are expected overnight and into Tuesday. Conditions will likely improve in central Wisconsin Tuesday, but improvement in the east will be slower as snow will linger longer in the east. && .GRB WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 4 AM CST Tuesday for WIZ020-031- 037>040-045-048>050-074. && $$ UPDATE.........Skowronski SHORT TERM.....MPC LONG TERM......TDH AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Grand Rapids MI
951 PM EST Mon Jan 30 2017 LATEST UPDATE... Update .SYNOPSIS... Issued at 300 PM EST Mon Jan 30 2017 An Alberta clipper system will bring snow tonight with accumulations in the 2 to 5 inch range by mid morning Tuesday. This will cause hazardous travel conditions to develop overnight and for the Tuesday morning commute. Lighter snow showers will linger through the day Tuesday and lake effect snow showers will develop Wednesday. Snow showers will likely linger into Thursday. && .UPDATE... Issued at 951 PM EST Mon Jan 30 2017 Will maintain the current headlines as is. We have received reports of around 3 inches of snow out of Newaygo and Montcalm counties north of the current Winter Weather Advisory, but HRRR data indicates the snow should be pivoting out of this area shortly. The heavier upstream snow over Wisconsin is aimed directly into the current advisory. && .SHORT TERM...(This evening through Wednesday night) Issued at 300 PM EST Mon Jan 30 2017 Primary short term fcst concerns involve determining probabilities for snow and assessment of how much snow will fall through the short term fcst period. A consensus of 12Z short range guidance remains fairly consistent in showing the Alberta clipper will bring 2 to 4 inches of snow tonight to most of our fcst area. Snow will be aided by moderate mid level frontogenetical forcing. The relatively higher end amounts within that range will occur near to south of I-96. Isolated higher amounts to around 5 inches seem possible mainly south of I-96 down toward AZO to JXN where some 12Z bufkit x-sections of omega w/height show potential for moderately stronger lift. Our winter wx advisory still looks excellent and no headline changes were necessary. Thx for coord on headline decisions APX/IWX/DTX. We trended pops higher for Tuesday as it looks like lighter snow showers will linger through the day on the back side of the system with fairly deep moisture still in place. Additional accumulations of around an inch or less are anticipated from mid morning Tuesday through Tuesday afternoon. A few light snow showers and flurries will linger Tuesday night followed by development of west to wnw flow light lake effect snow showers on Wednesday as h8 temps fall from around -8 to -10 C at 12Z Wed to -13 to -15 C by 00Z Thur. The relatively best chc for those will be found over our nw fcst area where deeper low level moisture is fcst along with higher delta t/s into the upper teens by the afternoon. We trended pops up for snow showers Wednesday mainly north of a line from KMKG to KRQB. .LONG TERM...(Thursday through Monday) Issued at 300 PM EST Mon Jan 30 2017 The long term period starts out with a broad mid level trough situated across the Great Lakes Region which persists into Friday. The airmass will be cold enough for lake effect but the moisture will be very shallow...generally 850 mb or less. Thus the potential for measurable precipitation looks low and I will keep the forecast that way. Ridging moves in for Saturday. This should be a dry day. With limited cloud cover and good radiational cooling...the day will start of quite cold...but temperature should moderate slightly as warm air advection begins to develop. A cold front pushes in for Saturday night into Sunday. Some snow showers should accompany the passage of this system. The DGZ becomes moist and there is some lift. Models are in relative agreement with this system. Will feature relatively high POPs for the passage of this system. On Monday or Tuesday the models are showing a low pressure system taking a track south of MI. Once this system goes by...northerly flow will strengthen. That will result in a cooling trend to the temperatures. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 753 PM EST Mon Jan 30 2017 A clipper system moving through the Great Lakes tonight will bring deteriorating aviation conditions to all of the TAF sites. Conditions have all already dipped to LIFR in spots in western Lower Michigan. A trend towards IFR/LIFR will continue tonight. On Monday, IFR conditions should be prevalent in the morning, slowing improving to MVFR towards evening. Light to Moderate snow will persist through this evening. There may be a break in the snow overnight, before filling in once again towards daybreak. The low ceilings will remain a constant once they arrive at each TAF site. Winds will be southerly tonight and shift to the west through the course of the day on Monday. && .MARINE... Issued at 300 PM EST Mon Jan 30 2017 A small craft advisory will be in effect from late this afternoon through tonight into Tuesday. Wave heights will subside to below sca criteria north of Holland by mid morning Tuesday through Tuesday afternoon. However wave heights will stay up around 4 to 5 feet south of Holland through Tuesday afternoon where the sca will remain in effect. && .HYDROLOGY... Issued at 155 PM EST Mon Jan 30 2017 River levels continue above normal across the area, including some minor out-of-bank flooding. Advisories continue for: the Grand River At Ionia, the Looking Glass River Near Eagle, and the Maple River At Maple Rapids. River levels should slowly fall into the weekend. Cold temperatures Wednesday night into the weekend will cause ice formation on area rivers. The snow expected tonight into Tuesday and Saturday night into Monday should have little effect on the river levels. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Winter Weather Advisory until 11 AM EST Tuesday for MIZ050- 056>059-064>067-071>074. LM...Small Craft Advisory until 9 AM EST Tuesday for LMZ846>849. Small Craft Advisory until 5 PM EST Tuesday for LMZ844-845. && $$ UPDATE...Duke SYNOPSIS...Laurens SHORT TERM...Laurens LONG TERM...MJS AVIATION...Duke HYDROLOGY...63 MARINE...Laurens
Area Forecast Discussion
National Weather Service Indianapolis IN
940 PM EST Mon Jan 30 2017 .UPDATE... The NEAR TERM Section has been updated below. && .SYNOPSIS... Issued at 300 PM EST Mon Jan 30 2017 An upper level disturbance will skirt north of the area tonight and may bring a few snow showers to northern and northeastern portions of central Indiana through early Tuesday morning. Another weak wave may bring a few flurries or snow showers to central Indiana late Tuesday night into Wednesday morning as well. Little or no accumulation is expected with either system. The remainder of the week into the early portion of the weekend will be dry, with the next chance for precipitation coming late in the weekend as a system moves through the Ohio and Tennessee valleys. && .NEAR TERM /OVERNIGHT/... Issued at 940 PM EST Mon Jan 30 2017 Surface analysis this evening shows a quick moving low pressure system over Wisconsin diving southeast toward NE Indiana and NRN Ohio. Southerly surface flow was in place across Central Indiana ahead of this system. Radar shows areas of snow across Michigan and NRN Ohio...well northeast of Central Indiana. Farther upstream...some snow was found across southeastern Wisconsin diving southeast also. Models suggest ongoing warm air advection to wane overnight...however clouds and southerly flow should prevent too much in the way of temperature falls. HRRR suggests any the precip associated with the approaching low should remain well north of Indy metro...but may brush past our far northeast counties...Muncie and Kokomo overnight. Confidence remains low though as dew point depressions are expected to remain rather large and deep saturation is not expected. Thus the most likely type of precip will be just a stray flurry and have continued to mention the ongoing flurry chances northeast. Confidence remains low. && .SHORT TERM /Tuesday through Thursday/... Issued at 300 PM EST Mon Jan 30 2017 Low chances for light snow will persist across the far northeast into Tuesday morning before ending as the wave exits. Another weaker wave will slide through the area late Tuesday night into Wednesday morning, and at least a period of saturation in the dendritic growth layer is noted along with moderate midlevel frontogenesis. Thus, will carry flurries or a slight chance of light snow showers during this period. Again, expect little or no accumulation. The remainder of the short term will be dry as high pressure noses into the area. Consensus temperatures appeared generally in the ballpark with minor tweaks per low level thickness progs. && .LONG TERM /Thursday Night through Monday/... Issued at 230 PM EST Mon Jan 30 2017 Quiet and seasonably cool weather will occur late this week into early next week with the exception of Saturday night and Sunday. Models indicate a somewhat zonal upper flow Thursday night through Saturday with high pressure moving east across the area. The GFS indicates a chance of snow around Friday as a weak upper disturbance moves by...while other models and SuperBlend remain dry. A stronger upper disturbance will move through around Sunday and the GFS and Canadian model indicates a weak low pressure system will move across the Ohio valley. This continues to be our best chance of precipitation...although some models have backed off a little on precipitation amounts. There are some issues with precipitaion type...but blended low level thickness lean towards snow Saturday night changing to mixed precipitaion or rain over central and southern sections Sunday. The Canadian and European models are a little faster this run and Sunday night and Monday should be dry as highs pressure builds in from the northwest. Tweaked temperatures to be a little cooler central and north Sunday. Otherwise...SuperBlend temperatures seem reasonable. && .AVIATION /Discussion for the 310300Z KIND TAF Update/... Issued at 923 PM EST Mon Jan 30 2017 Starting to see some surface gusts around 20 kts as the low level jet begins moving into the area. Will increase the winds on the update. Previous discussion follows. Patch of MVFR ceilings around 025 over northeast Illinois may move over the KLAF terminal for a time this evening, otherwise expecting some layered cloud above 050 at the terminals tonight. Some potential for ceilings 025-030 currently dropping southeast through southern Minnesota to work its way into the KLAF/KIND terminals after 310700Z. Model data suggest a low level jet around 50 kts will begin nosing into the area after sunset, resulting in a threat for low level wind shear. Questionable on how established the nocturnal inversion will become tonight given increasing surface winds, but appears the inversion top will be around 008-012 this evening, rising to 015-020 by the pre dawn hours of Tuesday. Surface winds 180-200 degrees at 6-10 kts this evening will gradually veer to 250-270 degrees at 11-15 kts towards daybreak. Occasional surface gusts 20-25 kts possible towards/after 310600Z if the low level jet can temporarily break through the nocturnal inversion. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...NIELD NEAR TERM...Puma SHORT TERM...NIELD LONG TERM...JH AVIATION...JAS
Area Forecast Discussion
National Weather Service Marquette MI
710 PM EST Mon Jan 30 2017 .SHORT TERM...(This evening through Tuesday) Issued at 403 PM EST MON JAN 30 2017 Water vapor imagery and RAP analysis show a deep trof extending s into the eastern CONUS. Vigorous shortwave that was over BC 24hrs ago has raced ese into the Upper Mississippi Valley. As suspected yesterday, the deep trof to the e is suppressing this wave on a more southerly course. Zone of waa/moist isentropic ascent underneath left exit of 140kt upper jet and within a band of fgen is supporting a narrow band of mdt to locally hvy snow that has spread across northern MN ese to e central WI. The ne fringe of the snow area (light snow) is just brushing far western Upper MI from Ontonagon/Ironwood toward Iron River. Otherwise, portions of the central and eastern fcst area enjoyed sunny skies for awhile during the morning into the aftn. Much of the area is now at least mostly cloudy. With vigorous shortwave now tracking ese into southern WI, northern portion of the snow extending back from WI into ne MN will diminish with time as it shifts ese. This diminishing of the snow will be a result of the strong waa/isentropic ascent region becoming increasingly separated from this portion of the pcpn area. Radar trends already show this diminishing trend getting underway. Expect some -sn/flurries to make it into central Upper MI this evening with slightly (emphasis on slightly) heavier snow along the MI/WI border. Wind fields overnight show weak sfc troffing extending n into scentral Upper MI from sfc low tracking across WI. With this trof resulting in light easterly winds across Lake MI into s central Upper MI and with 850mb temps around -9C over the lake, expect more persistent -sn in that area thru the night. In Menominee County, this should push snow accumulations into the 1-2 inch range for the tonight period. Elsewhere, where snow does occur, snow accumulations tonight will be less than 1 inch. On Tue, fcst area will be the cyclonic side of a 150kt upper level jet streak, with a tight isotach gradient, pushing from the Dakotas toward far northern IN. Being on the cyclonic side of the jet, models show a band of deep layer qvector divergence across the area on Tue. With deep moisture present, conditions will be favorable for the development of -sn during the day. Over the w, passage of sfc trof bringing a wind shift to an upslope wnw direction under 850mb temps around -10C will aid snowfall. A couple of inches of snow accumulation will be possible in that area with the rest of the area seeing accumulations around 1 inch. .LONG TERM...(Tuesday night through Monday) Issued at 340 PM EST MON JAN 30 2017 The main forecast highlights into next week will be chances for LES across the northwest and then west wind snow belts through the middle/end of the week with the arrival of a much colder, arctic air mass. This will also promote more seasonable temperatures compared to recent. A few days we could see highs only climb into the teens across the area with wind chill values at night dropping below zero across much of the area. Then as high pressure begins to drop southeast across the region through the weekend, the LES will at least diminish in intensity if not completely in some locations. Towards the end of the weekend, a system is progged to move through the region and will bring a chance for system snow across much of the area. Tuesday night expect system snow to transition over to predominately in the west and northwest wind snow belts. Progressing into Wednesday, as shortwave energy digs south, a surface trough will push south swinging a cold front across the area. As a result, expect falling temperatures through the afternoon hours. Given the enhanced synoptic lift, would not be surprised if LES becomes enhanced and extends further downstream than typical. With the broad synoptic lift, light snow may even be able to develop into far south central portions of Upper Michigan. Expect winds to veer around to the west-northwest and increase in speed after the front passes through with decent post frontal pressure rises and steepening low- level lapse rates due to increasing cold air advection. These winds will linger through the overnight hours through much of Thursday as another shortwave clips the region and brings additional cold air advection. Therefore, expect wind chill values below zero across the entire area Thursday morning. The coldest wind chills are expected across the interior west. Expect some improvements temperature wise on Thursday, but not much given the cold air advection and gusty winds. Given the above mentioned colder, arctic air mass expect LES is expected to linger Wednesday night through Friday. With 850mb flow taking more of a west-northwest orientation throughout the time period, expect the LES to be confined more to the west wind snow belts, but some LES bands may briefly meander into the northwest wind snow belts throughout the middle/end of the week. There are a few caveats that may inhibit LES from becoming heavy at times, especially towards the end of the week. With the cold arctic air mass in place, forecast soundings are showing quite a bit of low- level dry air and thermal profiles above the DGZ, especially across the west. Friday into Saturday another shortwave will dig southeast across the region pushing broad longwave troughing east of the region. As a result, large-scale subsidence will begin to take over as heights rise and surface high pressure moves just south of the area. This will allow the LES to weaken and diminish from west to east. Medium range models are in good agreement with another system lifting northeast across the area Saturday night through Sunday bringing another chance for system snow to the area. Then LES is expected to kick back in; however, there are some fairly significant differences between the ECMWF and GFS with 850mb temperatures and wind directions. Therefore, at this time have opted to stay more pessimistic with PoPs for the beginning of next week due to the uncertainty in development and location of LES. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 638 PM EST MON JAN 30 2017 A disturbance tracking ese across the Upper Mississippi Valley will brush the forecast area with light snow mainly this evening. At KIWD, conditions that were IFR a couple of hours ago have now lifted to MVFR conditions early this evening as -sn has diminished. At KCMX/KSAW, MVFR conditions will develop in the next couple of hours this evening and then will prevail at all terminals thru Tue with some -sn possible at times. As a light upslope westerly wind develops Tue morning at KIWD/KCMX, it`s possible cigs could fall to IFR at those terminals. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 340 PM EST MON JAN 30 2017 South winds of 20 to 30 knots will decrease in speed overnight into Tuesday as a clipper system moves south of the area. Through the day and overnight hours on Tuesday south winds will veer around to the northwest, with speeds around 15 to 25 knots. Wednesday through Friday, expect the north-northwest winds to ramp up as cold air advection increases across the lake. Wind speeds are generally expected to be 20 to 30 knots with gale force gusts possible, especially late Wednesday through Friday as surface to 700mb flow becomes more unidirectional. On Saturday as cold air advection shifts east of the region and surface high pressure drops southeast, expect winds to lessen and back to the southwest. With another system progged to develop across the northern plains and lift northeast across the lake on Sunday, expect southwest winds veer northwesterly and increase in speed to around 25 knots, especially on the eastern half of the lake. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...Ritzman AVIATION...Voss MARINE...Ritzman
Area Forecast Discussion...UPDATED
National Weather Service Norman OK
838 PM CST Mon Jan 30 2017 .UPDATE... Lowered overnight lows tonight a few degrees. Decreased surface dewpoints tonight and Tuesday. && .DISCUSSION... Mostly clear and quiet weather can be expected tonight. Decreased overnight lows in most locations as light winds and mostly clear skies should promote good radiational cooling in a dry airmass. Surface winds will become weaker during the night. There will be a large gradient in surface temperatures tonight between colder valleys and warmer ridgetops due to a strong low level temperature inversion. Decreased surface dewpoints tonight based on latest surface observations and HRRR model output. Most model output appeared to be too high with surface dewpoint depiction tonight into Tuesday. Thus, adjustments were made. Although the air will remain very dry on Tuesday, light surface winds and slightly lower temperatures should keep fire weather conditions below elevated or critical levels. MBS && .PREV DISCUSSION... /issued 548 PM CST Mon Jan 30 2017/ AVIATION...31/00z TAF Issuance... VFR conditions are expected to prevail through the period. Light to moderate southwest winds will decrease through the overnight, becoming more westerly. A gradual wind shift will occur through the period, with most locations becoming northerly and northeasterly by morning. Winds will remain light, 5 to 10 kts through Tuesday. Kurtz PREV DISCUSSION... /issued 318 PM CST Mon Jan 30 2017/ DISCUSSION... A weak cold front will move south across most of Oklahoma by noon on Tuesday, bringing only slightly cooler air into the region. A stronger front will bring a much more noticeable drop in temperatures on Wednesday. With very dry air in place, no precipitation is expected with either front. However, moisture will begin to return late in the week in response to an approaching shortwave trough aloft. By Saturday, relatively very warm and moist air will be lifted over the cooler air near the ground, resulting in isentropic lift and its associated higher chances for rain. As the shortwave trough moves away on Sunday, drier air will arrive in Oklahoma and north Texas, bringing an end to the rain chances and the extensive cloud cover that is expected from Thursday through Saturday night. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 36 66 35 56 / 0 0 0 0 Hobart OK 33 66 33 55 / 0 0 0 0 Wichita Falls TX 37 69 39 64 / 0 0 0 0 Gage OK 30 62 31 50 / 0 0 0 0 Ponca City OK 33 61 33 52 / 0 0 0 0 Durant OK 39 71 45 66 / 0 0 0 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...None. TX...None. && $$ 04/17
Area Forecast Discussion
National Weather Service Raleigh NC
959 PM EST Mon Jan 30 2017 .SYNOPSIS... Cold high pressure will crest overhead tonight, while a warm front will lift rapidly northeastward, and across our region Tuesday morning. Mild southwesterly flow will follow and prevail through mid- week. && .NEAR TERM /THROUGH TONIGHT/... As of 955 PM Monday... A weak ridge of high pressure is currently centered over eastern NC, while northwest flow continues aloft on the backside of the departing upper trough axis. Biggest forecast issues overnight are 1) the potential for orographic cirrus late and 2) low temperatures, which have plummeted under the high pressure and clear skies, particularly in the northeast. A favorable synoptic pattern with 50kt WNW flow at 700mb and a fair amount of high level moisture advecting in from the NW should lead to orographic enhancement of the thin cirrus approaching from the mid-Mississippi and Missouri River Valley Regions. Partly to mostly cloudy skies are possible in the west by sunrise. This may have some late impact on overnight lows in the western piedmont. Meanwhile, RAP soundings suggest the early cooling this evening and resulting nocturnal inversion noted in the 00Z raob at GSO will hold through the night and a southwest wind developing in response to a weak warm frontal passage will be light. Used the coldest guidance (MET MOS) to lower overnight lows in the mid 20s to lower 30s, coldest northeast. && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... As of 1200 PM Monday... The aforementioned clipper low will track through the Lower Great Lakes into New England Tue/Tue night, keeping a relatively tight MSLP gradient in place over the Carolinas. Warm advection via a breezy southwest low-level flow will result in a significant rebound in temperatures on Tue, with highs climbing above normal, ranging from the upper 50s near the VA border to the lower 60s near the SC border. Expect 0 chance for precipitation with a dry/stable/capped airmass in place over the region, though some cirrus (AOA 15 KFT) may advect into the region from the west via speedy westerly flow aloft. With a modified airmass in place, expect lows Tue night to be a good 10F warmer than tonight, in the lower 40s. -Vincent && .LONG TERM /WEDNESDAY THROUGH MONDAY/... As of 340 PM Monday... Broad low-amplitude troughing over the Southeast US will yield quasi- zonal flow aloft through the remainder of the work week, which will preclude significant moisture advection northward into the region and limiting rain chances along a cold front that is forecast to move south through the region Wednesday night/early Thursday. Central NC will see another mild day ahead of this front on Wednesday with temperatures topping out in the upper 50s/near 60 north to mid/upper 60s south on Wednesday. The front will stall near/just south of the NC-SC state line Thursday and into Friday. Light precipitation will attempt to develop/overspread the area late Thursday night and into Friday as weak cyclogenesis ensues along the front. However, upper support is greatly lacking with continued deep westerly flow limiting moisture availability. For these reasons, believe bulk of precip will stay south and east of the area with best precip chances across the Sandhills and southern coastal plain counties in proximity to the surface wave/front. Do not expect any p-type issues, with just a cold rain expected. After seasonably high temps in the 50s on Thursday, the clouds and light rain on Friday will keep temperatures generally in the 40s. Reinforcing surface high pressure will build into the area on Saturday into Saturday evening. Meanwhile, Pacific shortwave energy traversing the CONUS within the progressive low-amplitude flow is forecast to reach the Lower MS and Tn Valleys Sunday morning and then cross the area late Sunday-Sunday night. Southerly warm moist air conveyor feed ahead of this system will support increasing precip chances during the day on Sunday. If precipitation starts/moves into the area early enough Sunday morning, in-situ cold air damming could support a brief period of frozen precip across the northern/northwest piedmont, before changing over to all rain by the afternoon as a substantial warm nose aloft spreads over the area. At +140 hours out, it is way too early to get bogged down with model details, especially when dealing with transitional winter precip types. So for now, will advertise the expected predominate precip of rain only, while continuing to follow model trends as we get closer in time. Based on latest model timing, Precip looks to wind down Sunday evening/ night as the system exits offshore. Central NC looks to be between systems on Monday, which should yield mostly dry conditions during the day. However, precip chances could return as early as Monday night/early Tuesday with models hinting at another damming scenario unfolding for Tuesday. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... As of 700 PM Monday... High pressure will quickly crest over NC early tonight, then move offshore and yield to a warm front that will lift northeastward across the Srn Middle Atlantic states Tue morning. Calm to light Wly to SWly surface winds will result through most of tonight. The warm frontal passage Tue morning --and associated arrival of a WSWly low level jet characterized by 40-50 kt winds at 2000 ft, above a cool and stable surface layer-- will favor the occurrence of low level wind shear between 10-15Z Tue. The strong winds within the nocturnal inversion will turbulently mix to the surface with diurnal heating around 15Z, and manifest at that time as strengthening and gusty SWly surface winds, and an end to the earlier LLWS. Outlook: A lead cold front will settle through central NC with an accompanying brief chance of MVFR rain late Wed night-early Thu. The front will stall and waver over the Carolinas late in the week, with an accompanying better chance of mainly light rain, and sub-VFR conditions, centered around the day Friday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...MWS NEAR TERM...SMITH SHORT TERM...VINCENT LONG TERM...CBL AVIATION...MWS