Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/05/17

Area Forecast Discussion...corrected date
National Weather Service La Crosse WI
549 PM CST Mon Dec 4 2017 .SHORT TERM...(Late Afternoon through Tonight) Issued at 304 PM CST Mon Dec 4 2017 High Impact Weather Potential: First things first, can`t rule out an isolated severe storm through 7 pm as the front arrives. Thereafter, wind remains the big story through the night, but also watching the potential for a little accumulating snow for a time this evening, especially north of a line from about Charles City, IA to Black River Falls, WI. A true tale of two seasons ongoing across the region at the moment, with very mild air drawn northward into our area ahead of an approaching strong cold front, just pushing into parts of southeast MN and northeast IA as of 20Z. That feature is of course tied to a strengthening surface cyclone expected to lift north over western Lake Superior this evening, sending much colder air in our direction along with a rapidly tightening pressure gradient. Temps in many areas have approached (or will approach shortly) record values well into the 50s and lower 60s for December 4th (wow!), with a broken line of convection now developing along the incoming sharp wind shift, aided by 500-750 J/kg MUCAPE pooled ahead of the front. As this line progresses east, would anticipate it continuing to develop through 6-7pm, and with strong 0-2km shear in place, can`t rule out a few stronger to severe storms, especially east of the Mississippi River, though we`ll have to overcome some residual surface-based inhibition as well as a notable warm layer up around 800mb. RAP soundings suggest we just may do this across far southern areas, and do have a small concern for low-topped supercell development so definitely something to watch closely. That severe threat will end quickly just after 00Z as the cold front clears the area, with steepening low level lapse rates in strong cold advection through the evening promoting mixing up to 850-800mb. Solid area of 40-50 knots through the mixed layer continues to suggest many areas will see surface gusts of 45-50 mph, especially for a few hour period just behind the front. Can`t rule out a few gusts to 55 mph, especially west of the Mississippi River in the tightest gradient but overall, just a windy period through the evening and night, with speeds gradually subsiding later tonight with slowly weakening mixed layer flow. Also of interest is the potential for a few hour period of snow to impact western and northern areas this evening, associated with deformation forcing as the upper shortwave swings across the area. Recent trends suggest this feature may be a little more robust farther east into our area, with the potential for a half-inch to maybe one inch of accumulation north of a Charles City, IA to Black River Falls, WI line. This should be short-lived, but it`s possible snow could fall heavily for a brief period, with some messy travel possible while snow is ongoing given the gusty winds as well. At the moment, don`t see the need for a Winter Weather Advisory just yet but will hit the potential impacts a little harder in graphical form/social media. .LONG TERM...(Tuesday through Monday) Issued at 304 PM CST Mon Dec 4 2017 Steady as she goes in the temperature department right on through the weekend, with our well-discussed and rather stable western North America ridging pattern teleconnecting well to broad upper troughing centered over the Great Lakes. That of course opens the doors to persistent shots of colder air working down across the area, as well as the likelihood for periodic shortwaves to also traverse the flow. As is typical is such setups, the timing and placement of each wave remains rather low confidence beyond about 2 days, with already plenty of change noted in the position or even existence of said waves from just 24 hours ago. Given such uncertainty, a blended approach remains best with regard to any precipitation chances, but overall the pattern will not be very conducive to any big chances for significant wintry precipitation the next 7 days. With that said, a few stronger waves could certainly put down some light snow accumulation, with one target toward later Thursday night or Friday with consensus guidance hinting at a stronger wave crossing the area with a modest frontogenetic response somewhere nearby. Outside of that, periodic flurries or light snow showers could occur with just about any shortwave, but with the larger message being steered toward an extended stretch of near to below normal temperatures for early and mid December (a HUGE change from the past 2 weeks). && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 549 PM CST Mon Dec 4 2017 Through 7 PM, a line of showers and scattered storms located along and ahead of a cold front will move east through western Wisconsin. With this line already east of the TAF sites, the showers and storm were not added to the TAFs. In the wake of this front, ceilings will become MVFR. These MVFR have already moved into KRST and they will move into KLSE around 05.01z. Overall, the HRRR is handling the deformation band the best. It shows that some light snow may fall at KRST between 06.04z and 06.06z. As a result, included a MVFR visibility at that time. By 06.09z, the deformation will be pulling out of the TAFs and the ceilings will become VFR. Strong west winds will be seen at the TAF sites into Tuesday. The strongest winds will be from 05.03z and 05.13z when the wind gusts will be in the 35 to 45 knot range. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...Wind Advisory until 6 AM CST Tuesday for WIZ017-029-032>034- 041>044-053>055-061. MN...Wind Advisory until 4 AM CST Tuesday for MNZ079-086>088-094>096. IA...Wind Advisory until 4 AM CST Tuesday for IAZ008>011-018-019-029- 030. && $$ SHORT TERM...Lawrence LONG TERM...Lawrence AVIATION...Boyne
Area Forecast Discussion
National Weather Service Duluth MN
916 PM CST Mon Dec 4 2017 .UPDATE... Issued at 904 PM CST Mon Dec 4 2017 Based on latest trends of RAP and HRRR which move snow into Wisconsin rather than Minnesota decided to replace portions of the winter storm warnings with advisories in Minnesota. Meanwhile in Wisconsin, replaced the wind advisory with a winter weather advisory as more snowfall is expected there in addition to the winds so wrapped those two into one product. Latest water vapor imagery shows a comma head forming over Minneapolis with a deformation band extending northward. This is progged to move across NW Wisconsin, so upped snowfall totals there by quite a bit and am still probably too low with 2-4 inches expected. Considered moving to just winter weather advisories in Minnesota, but a little concerned that the deformation band may move northward and thus decided to keep the arrowhead in the wsw, but the probability of that happening is less than 50 percent; though, there is a strong northward surge in WV imagery though, so we`ll see. && .SHORT TERM...(This evening through Tuesday) Issued at 408 PM CST Mon Dec 4 2017 Things are evolving very rapidly this afternoon as a rapidly deepening low pressure area is centered between the Twin Cities and Duluth. This low is forecast to deepen around 20 mb to somewhere around 970 mb by midday tomorrow north of Lake Nipigon. Large scale forcing for ascent is becoming intense as the primary upper vort max approaches the region from the northwest Iowa/northeast Nebraska/southeast South Dakota area. Rather significant instability is in place in both terms of CAPE and EPV, which will result in robust vertical motion fields for the next 12 to 18 hours as the main lobe of forcing moves across northern MN/northwest WI. The other result of this is that thunderstorms will be somewhat widespread across northwest WI thru this evening, and with the lower troposphere being so cold this time of year, it will not take much to get hail out of the stronger updrafts. The rain/snow line is currently roughly from near Lake Winnibigoshish to just east of International Falls, and this transition zone will rapidly collapse eastward over the next 3-6 hours as the surface low deepens and moves across Duluth and on to western Lake Superior coincident with the collapse of the inverted trof across NCent MN that has thus far kept the colder air at bay. While the period of intense lift and heavy precip will be relatively short, there will be a 6-9 hour period if strong to intense precip/snow rates. We have tried to reflect a majority of the precip falling tonight and early Tuesday morning with the primary deformation area, but light snow will persist for much of Tuesday within a large area of wrap around saturation. The other big story with this system will be a 9-15 hour period of very strong northwest winds later tonight and Tuesday morning when the super-position of strong cold advection, a very strong gradient, and very strong pressure rises will be bullseyed over northeast MN. The initial heavy wet snow will cling to trees and power lines, and the winds would likely be strong enough to bring down some weaker branches/trees anyway, so some power outages with this system seem likely. We will also need to keep a close eye on the potential for a gravity-wave forced snow band late tonight/Tuesday morning across Douglas/Bayfield Counties as the intense low level/cross northshore ridge and strong cold advection are ideal for trapping gravity wave energy. We may need to up snow totals in these areas if this feature sets up over land. .LONG TERM...(Tuesday night through Monday) Issued at 408 PM CST Mon Dec 4 2017 Winter is back and it`s here stay. Much colder temperatures are expected mid week through this weekend across the Northland with highs as cold as the teens as lows below zero towards late-week. Lake effect snow will linger across the Wisconsin snow belt region Tuesday night through Wednesday night, then the next chance for widespread light snowfall arrives Thursday night into Friday when a clipper will bring light snow to the region and a round of lake effect snow afterwards continuing through the weekend. Mid to late week the primary concern will be the cold temperatures across the Upper Midwest. Tuesday night into Wednesday the stacked low that brought the return of the winter weather will be over far northeast Ontario tracking northeast towards Hudson Bay. Meanwhile a strong mid/upper level ridge will be building over the west coast leading to strong north-northwest flow across the Great Plains and Upper Great Lakes at low, mid, and upper levels of the atmosphere. A reinforcing wave of colder air will arrive Wednesday night into Thursday, then a subtle mid-level trough will track almost due south across northern Manitoba and northwest Ontario to bring another chance of light snow and even colder temperatures Thursday night into Friday. By Friday night 850mb temps will be the coldest for this stretch with -20C to -25C air aloft. The parade of weak disturbances continues into the weekend as some weak ridging and slight warming at low levels across the Upper Midwest precedes yet another mid-level shortwave trough, this time coming out of Canada Prairie into the Upper Great Lakes Sunday into Monday. Behind this disturbance, extremely cold air on the order of -25C to -30C at 850mb is possible Monday night into Wednesday which would result in frigid, well below normal temperatures - perhaps *high* temperatures below zero by Wednesday. High temperatures in the teens to 20s Wednesday through Monday, except on Sunday when highs may reach the low 30s for parts of east- central MN into northwest Wisconsin. Lows in the single digits above zero Tuesday night, then single digits below or above zero Wednesday, Thursday, and Friday nights, coldest in far northern Minnesota. Lows "warmer" in the single digits to teens above zero Saturday and Sunday nights. While these temperatures really aren`t that out of the ordinary for mid December (average highs are in the low 20s, lows in the mid-upper single digits for Duluth), the very warm weather over the past two weeks will make this rapid change from warm to cold feel more extreme. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 534 PM CST Mon Dec 4 2017 A strong deepening low pressure is crossing the area this evening. Prevalent IFR expected through 07Z despite improving ceilings, snowfall coupled with blowing snow should drop vsbys down to 1 SM in snow bands. Winds will be strong and gusty with gusts to 35 kt possible throughout the period - a wind shift will occur as the low passes overhead changing direction to be predominately nwly as it exits Tuesday. && .PRELIMINARY POINT TEMPS/POPS... DLH 13 16 8 18 / 90 30 20 10 INL 10 13 5 14 / 100 60 40 20 BRD 11 15 9 19 / 100 10 10 10 HYR 15 17 9 20 / 80 30 30 30 ASX 19 22 13 22 / 90 40 50 50 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...Winter Weather Advisory until noon CST Tuesday for WIZ001>004- 006>009. Winter Weather Advisory from midnight Tuesday night to 6 PM CST Wednesday for WIZ004. Lakeshore Flood Advisory until 6 PM CST Tuesday for WIZ002. MN...Winter Weather Advisory until noon CST Tuesday for MNZ025-026- 033>038. Winter Storm Warning until noon CST Tuesday for MNZ011-012- 019>021. Winter Storm Warning until 6 AM CST Tuesday for MNZ010-018. LS...Small Craft Advisory until 10 PM CST this evening for LSZ121- 143>148. Gale Warning until 10 PM CST Tuesday for LSZ121-140>145-148. Storm Warning until 10 AM CST Tuesday for LSZ146-147. Gale Warning from 10 AM to 10 PM CST Tuesday for LSZ146-147. && $$ UPDATE...Wolfe SHORT TERM...Miller LONG TERM...JJM AVIATION...Wolfe
Area Forecast Discussion
National Weather Service Des Moines IA
616 PM CST Mon Dec 4 2017 ...Updated Aviation Discussion... .SHORT TERM.../Tonight through Tuesday/ Issued at 317 PM CST Mon Dec 4 2017 Confidence: Medium to High Models handling of current system overall decent with elongated trough over MN/IA and two low centers expected to consolidate into one as the storm deepens through 12z Tuesday. At 19z cold front nearing the I35 corridor with warm sector beginning to be pinched off to the west and strong cold air advection replacing the mild air. Surface moisture plume/axis of 50 to 55F dewpoints advecting east/northeast with the surface front. Current SPC mesoanalysis shows sufficient shear along with up to 500 J/kg MLCAPE just ahead of the boundary. However a weak cap remains of 25 to 50 j/kg MLCIN. SPC upgraded the far southeast to slight risk through day1. Though it will be close...with the current convective initiation just northwest of Kansas City it is likely that the bulk of any stronger storm development this afternoon/early evening will track east northeast and just miss our forecast area in the southeast... tracking into eastern Iowa and western Illinois/Missouri. The window of opportunity for any severe storms will be very short...from roughly 3 pm to 6 pm as front slides east. Will monitor for any development further west...but current trends/SPC HRRR forecast both suggest this evolution. Winds remain the big story and soundings continue to confirm strong northwest winds with strong subsidence this evening into the overnight hours. Sustained northwest winds to 30 to 35 mph with gusts to 50 mph still in the offing so will not make any changes to wind advisory. Farther northwest in the forecast area...departing low still expected to develop deformation axis which just clips the northwest counties east to near KMCW. Though snow amounts are forecast to be rather light and less than an inch ...some blowing snow may occur due to the strong winds expected to accompany the snowfall. Warm ground due to today`s high temperatures will likely temper some of the blowing snow as it either melts or sticks more readily for a time prior to lowering temperatures below 30 degrees. Window of opportunity for snowfall will be around 2 to 3 hours from just after 01z through 04z. Cold air quickly follows the departing system tonight into tomorrow. After lows in the teens northwest to the upper 20s southeast...highs tomorrow will likely only recover to the mid 20s northwest to the upper 30s southeast. Winds will remain brisk and again mix well into the afternoon. Model continue to depict a weak shortwave with little moisture...tracking southeast on the back side of the wave tomorrow morning/early afternoon. Have kept isolated flurries with passage of mid level clouds as destabilization may briefly add to snow shower/flurry chances tomorrow. .LONG TERM.../Tuesday night through Monday/ Issued at 317 PM CST Mon Dec 4 2017 Main change in upper pattern will have nearly been completed by the beginning of this period with broad amplified eastern trof in place. This will ensure that flow from Canada will be essentially unabated for the remainder of the week. Average temperatures will be from 20 to 30 degrees cooler than last week and back to below normal for the first time since mid November. Main concerns will be the various waves that drop into the western side of the trof and their timing and impact on the state. Models indicate a wave passing through on Tuesday night with sufficient lift for some deeper saturation. The production of some flurries appears somewhat likely across central portions of the state and have continued the threat. The thermal trof and cool north winds will persist on Wednesday and Thursday with deep northwesterly flow. Next system drops down for Friday into Friday night with some threat of light snow and some slight moderation in temperatures. After the passage of this system, some warmer air is expected to begin pressing eastward from the Plains into the weekend with slowly moderating temperatures. However, a reinforcing shot of colder air is expected by the end of the weekend as another wave dropping southeast reinforces the eastern trof. Overall, temperatures will remain at or below normal for much of the later half of the forecast. && .AVIATION.../For the 00Z TAFS through 00Z Tuesday evening/ Issued at 613 PM CST Mon Dec 4 2017 MVFR stratus with intermittent IFR stratus impacting northern Iowa this evening with the CAA. The strong winds will persist throughout the period with a possible lull or slight decrease in the winds Tuesday morning before the deep mixing develops again by the afternoon. However, the gradient winds seem to remain strong enough through Tuesday morning to keep at least wind gusts from 25-30 knot mentioned. This evening, expect some periodic wind gusts to 45-50 mph. && .DMX WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 3 AM CST Tuesday for IAZ004>007-015>017- 023>028-033>039-044>049-057>060-070. && $$ SHORT TERM...REV LONG TERM...Cogil AVIATION...Podrazik
Area Forecast Discussion
National Weather Service Sioux Falls SD
526 PM CST Mon Dec 4 2017 .SHORT TERM...(This evening through Tuesday) Issued at 318 PM CST Mon Dec 4 2017 Well advertised potent surface low and upper level trough will continue to dig across the northern and central Plains into tonight. This fast moving system will be a strong punch of colder air and a band of precipitation. The main precipitation player will be associated with the deformation band which currently extends from south central SD into eastern North Dakota. This band will continue to slide eastward through the evening hours, exiting to our east by midnight tonight. Frontogenetic forcing ahead of the deformation band has not really materialized as expected, which had delayed the onset of precipitation across the forecast area. The cold air advection and strong winds however remain on track. Winds will continue to gust to 35 to 45 mph with locally higher gusts to 55 mph possible through the evening. With the initial push of precipitation into south central SD and the highway 14 corridor in SD over the past few hours, we have received reports of rain freezing on powerlines and causing outages when combined with the strong winds. With the low and mid levels cooling rapidly this evening, expect the patchy freezing rain threat in these areas to quickly switch over to snow. Will add mention of freezing rain to the winter weather advisory in south central and east central SD. High res models such as the HRRR and NAM derivatives indicate the potential for localized convective enhancement with the stronger forcing arriving as the band of snow move approaches the I-29 corridor, then into southwest Minnesota. Think that brief heavy snow will be possible for areas mainly along and north of I-90, however the progressive nature of this system will limit snowfall amounts from piling up more than than 2 to 4 inches. Most locations will be closer to the 1 to 2 inch range, while amounts will generally be an inch or less in northwest Iowa. With the strong winds and "flash freeze" type conditions as the temperatures cool rapidly, travel conditions will be hazardous. Blowing snow and reduced visibilities will be a huge concern with near blizzard conditions possible during snowfall. Timing places the snow band in the FSD and SUX areas during the evening commute. Decided to expand the winter weather advisory further east into MN and southeast SD, generally following where an inch or more of snow is possible. Again, amounts are not as big of a factor in the advisory as the blowing snow and poor visibility conditions. Elsewhere, the wind advisory remains in effect for northwest Iowa and northeast NE where the winter weather advisory is not in effect. Skies will clear behind the exiting system tonight, with strong winds only decreasing a small amount overnight. Northwest winds remain windy into Tuesday, averaging 15 to 30 mph with higher gusts. Clouds will be on the increase late tonight and Tuesday as a reinforcing shot of cold air arrives with a trailing wave. Lows tonight reach the teens with highs in the 20s to near 30 on Tuesday. with the strong winds, wind chills will drop to near zero or a few degrees below zero late tonight. .LONG TERM...(Tuesday night through Monday) Issued at 318 PM CST Mon Dec 4 2017 With the focus on the ongoing storm system, did not make any alterations to the blended forecast in the mid and long range. Pattern remains cold in comparison to the recent weather pattern, but not extreme, with highs in the 20s and 30s. Northerly upper level flow pattern stick around through the end of the week, with a sharp ridge over the west coast and troughing over the Great Lakes region. Models hint at several weak waves dropping southward through the northern Plains during the week, however model timing of these waves remains uncertain. Precipitation chances remain spotty at best. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 520 PM CST Mon Dec 4 2017 Band of snow along the I-29 corridor as of 23Z will shift east into southwest Minnesota and northwest Iowa through 02Z...and shift further east into Central Iowa/Minnesota after 04Z. Strong northwest winds gusting to 45kts will reduce visibilities in band of snow. Northwest winds will gradually decrease overnight...but remain in the 15-30 mph range through much of the forecast period. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...Winter Weather Advisory until 8 PM CST this evening for SDZ038>040-050-052>070. Wind Advisory until midnight CST tonight for SDZ071. MN...Winter Weather Advisory until 8 PM CST this evening for MNZ071- 072-080-081-089-097-098. Wind Advisory until midnight CST tonight for MNZ090. IA...Winter Weather Advisory until 8 PM CST this evening for IAZ001. Wind Advisory until midnight CST tonight for IAZ002-003-012>014- 020>022-031-032. NE...Wind Advisory until midnight CST tonight for NEZ013-014. && $$ SHORT TERM... LONG TERM... AVIATION...BT
Area Forecast Discussion
National Weather Service Green Bay WI
516 PM CST Mon Dec 4 2017 Updated aviation portion for 00Z TAF issuance .SHORT TERM...Tonight and Tuesday Issued at 238 PM CST Mon Dec 4 2017 The latest RAP analysis and satellite/radar imagery show a strengthening area of low pressure moving northeast over east- central Minnesota early this afternoon. Widespread showers and isolated thunderstorms within the warm advection zone have mostly exited to the Upper Peninsula, though a few spotty showers and some drizzle remain. Expect this lull in the precip to continue for the rest of this afternoon, until a strong cold front, currently over southern Minnesota and central Iowa, moves across the region this evening. With the clouds and rainfall, winds have struggled to increase, but could still see some gusts to 30 kts through the start of the evening. As the cold front races across the area tonight, precip trends, and potential for strong gusty winds are the main forecast concerns. Tonight...As low pressure lifts northeast across western Lake Superior, a dynamic shortwave will push a cold front across the region during the evening. The latest HRRR suggests a broken line of showers will develop along the boundary, which should impact much of the area. Cannot rule out some thunderstorms along the front, given modest but sufficient elevated instability in place. Tend to think the wind gusts will continue to struggle in the warm sector ahead of the front, but the showers that are expected to develop could be capable of bringing down the stronger winds aloft. But the main push of wind will arrive behind the cold front, mainly after midnight. Bufkit soundings continue to indicate that wind gusts of 35 to 45 mph are likely, with some gusts up to 50 mph possible. The highest gusts should occur over central to northeast Wisconsin coincident with the highest boundary layer winds. As the comma head rotates through the area and temperatures fall below freezing, some snowfall is likely over parts of central and north- central WI late. Amounts should be relatively light, perhaps up to an inch over western Oneida and Vilas Counties. Temps in the upper 40s to mid 50s in the evening will fall into the 20s and 30s by daybreak. Tuesday...Wrap around snow showers will likely continue for most of the day across northern WI. Up to another inch looks possible. Otherwise, a tight pressure gradient to go along with cold advection and steep low level lapse rates will keep the strong gusty winds going through the day. Highest gusts should again occur over eastern WI where bufkit shows 35 to 45 mph will be possible. With coordination from surrounding offices, will extend the wind advisory for counties along and to the east of a Wautoma to southern Marinette line. High temperatures will be much colder than todays unseasonable readings, and range from the lower 20s to lower 30s. .LONG TERM...Tuesday Night Through Monday Issued at 238 PM CST Mon Dec 4 2017 The strong low pressure system will continue to influence the beginning of the long term period as it moves out towards the northeast. A few snow showers will linger on late Tuesday night into Wednesday morning, as lake effect mechanisms dominate the region with the wind flow across Lake Superior. Winds will remain primarily from the W/NW which will keep the heaviest snow showers concentrated in the Upper Peninsula of Michigan, but far northern Wisconsin could still see some isolated snow showers. Left flurry chances in the region through Wednesday until the mid levels begin to dry out overnight. Winds will slowly diminish starting Tuesday night, but some weaker gusts are still likely in the region. A drier and possibly more clear day is in store for Thursday, especially away from the influence of Lake Superior. Lake enhanced snow showers and flurries may continue to touch into northern Wisconsin, but otherwise a cooler and drier day is expected. Although timing may yet vary, a stronger piece of upper level energy is expected to come through on Friday for a brief chance to see some widespread snow showers. Due to the lack of available moisture and the anticipated speed of this system, overall accumulations are expected to be minimal. An additional chance will be over the weekend, again with a lack of moisture before we see a better chance of accumulations early next week with the third shortwave. Timing and placement on this third event is still too variable to determine. Temperatures through the extended will be much cooler than the start for December, and be 5-10 degrees below normal. && .AVIATION...for 00Z TAF Issuance Issued at 515 PM CST Mon Dec 4 2017 The lull in precipitation will come to an end as scattered showers and isolated storms develop along a strong cold front this evening. Strong south winds this evening will become southwest then west behind the cold front with gusts approaching 40 kts later tonight. A few hours of light snow is possible over north- central WI overnight within the comma head of the strong cyclone. Windy conditions will continue on Tuesday, with only light snow over far northern WI. Conditions are expected to mainly be IFR across the north, improving to MVFR later tonight into Tuesday. Further south mainly MVFR conditions are expected with VFr possible at times. && .MARINE... Issued at 238 PM CST Mon Dec 4 2017 South winds will continue to gradually increase this afternoon...with gale force gusts possible. Subsidence in the cold advection and dry slot tonight will produce southwest then west gale gusts with the potential of storm force winds toward the open waters. These conditions will persist into Tuesday before gradually tapering off on Tuesday night. && .GRB WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 6 PM CST Tuesday for WIZ022-038>040-048>050. Wind Advisory until 6 PM CST Tuesday for WIZ031-037-045-073-074. Wind Advisory until 6 AM CST Tuesday for WIZ005-010>013-018>021- 030-035-036. && $$ SHORT TERM.....MPC LONG TERM......Uhlmann AVIATION.......Kurimski MARINE.........MPC
Area Forecast Discussion
National Weather Service Grand Rapids MI
1003 PM EST Mon Dec 4 2017 LATEST UPDATE... Update .SYNOPSIS... Issued at 330 PM EST Mon Dec 4 2017 Southwest Michigan will see significant weather changes over the next 24 hours. Tonight will see rainshowers and even a few thunderstorms. Temperatures will stay in the 50s through midnight, then temperatures will fall quickly late tonight as a cold front comes through. The mercury will fall through the 30s on Tuesday, and into the 20s Tuesday night. The rain will change to snow late tonight into Tuesday, but it will remain light through Tuesday night. Accumulations will be less than an inch through Wednesday morning. A stronger push of snow showers is expected by Wednesday afternoon and Wednesday night when an inch or two is expected, localized amounts of four inches will be possible. The rest of the week will remain cold with high temperatures only around the freezing mark each day. Periodic snow showers will occasionally result in additional accumulations. && .UPDATE... Issued at 1003 PM EST Mon Dec 4 2017 Latest HRRR guidance has the line of convection currently over WI/IL weakening as it moves east. Skinny area of sfc based cape near 500 J/KG helping to fuel the line falls off by the time it hits lk MI. However elevated instability will still be present as the convection moves east overnight with a few hundred joules of MUCAPE progged. So a few rumbles may still occur overnight and some locally stronger wind gusts to 50 mph are possible if the stronger winds just above the sfc can be mixed down by the convection. Winds after fropa will be gusty as well as deeper mixing develops in the colder air. Strongest gusts near lk MI. && .SHORT TERM...(This evening through Wednesday night) Issued at 330 PM EST Mon Dec 4 2017 Major change to the region`s weather is on the horizon as a cold front comes through late tonight. Temps will fall through the 30s on Tuesday and into the 20s Tuesday night. Snow showers will began to add up, especially Wed afternoon and night. The very mild air with temps in the mid and upper 50s will hold through the evening, but then come crashing down once the front passes through about 09Z. The front could bring a brief period of gusty thunderstorms tonight too. The 40s will quickly vanish behind the front and much of Tuesday will fall through the 30s. There will be a bit of moisture immediately behind the front so we should see a few rain/snow showers early Tuesday, that will dry up toward mid day. The rest of day will be windy, but with just some flurries. The moisture continues to look less favorable for Tuesday night. Thinking the snow showers will continue, but they`ll be light. Any accums by daybreak Wed should be under an inch. A short wave swings through the upper trough over the Great Lakes Wed afternoon and Wed night when the lake effect snow will increase. This is the period when better accums should occur. Figuring an inch or two in most places along and west of U.S. 131, with isolated four inch amounts. An inch or less to the east of U.S. 131. Will issue a wind advisory for the lakeshore counties starting late this afternoon. Warm sector winds have already approached criteria and as the front moves in, the winds should only increase. Will run the advisory through Tuesday too as the cold advection continues to produce winds to 40 knots or greater. This is most likely for the lakeshore itself, as winds 10-15 miles inland may not make it to the 40 knot criteria. .LONG TERM...(Thursday through Monday) Issued at 330 PM EST Mon Dec 4 2017 Not much of a change in the long term forecast. The main themes remain colder than normal temperatures and periodic lake effect snow. A long wave upper trough is forecast to remain entrenched over the Great Lakes region through the period. Upper shortwaves will periodically dive through the Western Great Lakes so there will be periods of moderate to heavier snow. Timing these episodes are problematic at this time range but we should see periodic heavier lake effect snow right into the weekend and likely beyond. 850mb temperatures have remained fairly consistent from run to run with -12C to -16C temps common. Sunday looks a bit warmer now but still cold enough for lake effect snow to continue. Just beyond this forecast period out in the Tuesday through Thursday time frame of next week even colder air is forecast with -20C air rotating in from the north. Bottom line: periodic lake effect snow and colder than normal temperatures. Main impacts will likely be along and west of U.S. highway 131. Accumulating snows are likely in Western Lower Michigan. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 700 PM EST Mon Dec 4 2017 Line of tstms now getting into wrn WI and IL at 7 PM EST is expected to weaken once it gets to Lk MI later this evening. However we may still get some thunder and gusty winds as this convection comes through the area between roughly 04Z and 08Z. Also MVFR to IFR cigs and vsbys could accompany the heavier showers. Once the cold front comes through late tonight, the showers will end but MVFR cigs and gusty southwest winds will continue. Some light snow showers or flurries may develop Tuesday afternoon which could create reductions in vsbys, particularly at MKG and GRR. && .MARINE... Issued at 330 PM EST Mon Dec 4 2017 Gale warning will continue into Tuesday night. A few gusts toward 45 knots will be possible toward the Sable Points region, with 35 to 40 elsewhere. && .HYDROLOGY... Issued at 1257 PM EST Mon Dec 4 2017 Precipitation will fall as rain through tonight before colder air rushes in behind a strong cold front and precipitation transitions to snow. Total rainfall from this morning through Tuesday morning is expected to range between 0.25 and 0.70 inches, which will not be enough to cause significant rises on rivers and streams. Totals exceeding 0.5 inches will most likely occur along and north of I-96. A few thunderstorms may develop late this evening and overnight. These would produce locally heavier rainfall amounts, and could result in water ponding on roadways and low-lying areas. Precipitation from Tuesday afternoon into the weekend will fall as snow as temperatures remain below freezing. High snow-to-liquid ratios will result in some snow accumulations (especially near the lakeshore), but no significant liquid-equivalent accumulations. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Wind Advisory until 4 PM EST Tuesday for MIZ037-043-050-056-064- 071. LM...Gale Warning until 4 AM EST Wednesday for LMZ844>849. && $$ UPDATE...Meade SYNOPSIS...JK SHORT TERM...JK LONG TERM...Duke AVIATION...Meade HYDROLOGY...HLO MARINE...JK
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
857 PM CST Mon Dec 4 2017 .UPDATE... 857 PM CST No big changes planned to going forecast this evening. Strong cold front has breached our western CWA border and will sweep rapidly across the remainder of the CWA over the next 3-4 hours. Ahead of the front, have seen several sites tag wind advisory criteria gusts this evening as the low level jet ramped up. An area of showers and some t-storms will continue ahead of the front, though convection has been quickly weakening and lightning activity diminishing as the storms out run the narrow instability axis. Still could see some 50+ mph gusts in the heavier shower activity as it transports the higher momentum air to the sfc. Biggest change to going forecast was to beef up sky cover overnight into tomorrow morning as GOES-13 imagery shows expanding area of stratus over Iowa spreading quickly east behind the front. Have seen reports of flurries in the stratus deck, but as upper low lifts northeast would expect the flurry threat from this deck to diminish as it moves into northern IL. Other than the MET, most guidance is largely unaware of this stratus, leading to low confidence in how long it persists Tuesday. For now, just hung on to the lower clouds through mid-morning, but will need to monitor satellite trends overnight to see how it evolves. Forecast soundings for Tuesday show drying beneath the sharp frontal inversion, but given most models poor initialization of this cloudiness, not convinced they are handling the post frontal low level moisture well tomorrow either. No changes planned to the wind advisory. Could see a short period of slightly lower winds immediately behind the front, but as axis of strong pressure rises shifts east and low clouds prevent any decoupling, think it is possible we could see some near advisory level gusts again later tonight. - Izzi && .SHORT TERM... 254 PM CST Through Tuesday... Main forecast concerns/challenges are with the thunderstorm potential late this afternoon through mid/late evening, which now includes an increased threat for isolated strong to severe thunderstorms mainly across north central Illinois. Also, strong/gusty winds will continue into tonight with current wind headline still on track. In the near term, dry conditions in place as lacking focus in the area continues. However, this will likely change by mid to late afternoon as system to the west draws near. Have been monitoring convective trends over the last couple hours, with concerns growing for an increased threat of strong to severe storms across the region. Some limiting factors such as thick cloud cover and weaker instability are still noted and valid items to consider, but these trends have been showing that these could become offset later today into this evening at least across a portion of the CWA. Surface low continues to deepen across the midwest ahead of large upper level trough and strong vort max swinging across the region. Expect this low to further deepen through the night as it lifts across the western Great Lakes, with associated surface front pushing east the region. As large scale forcing quickly increases over the next couple of hours, will see convection develop over eastern Iowa into west central Illinois along and ahead of this front. While instability is in place across the region, observational trends and rap analysis indicating a narrow ribbon of MLCAPE situated right along this front. What`s also in place is weakening CIN, with short term guidance indicating this trend of weakening CIN may continue into this afternoon and evening into northern Illinois. Cloud cover in place may limit this trend, but strong forcing ahead of this system could offset this and allow further erosion. This is concerning, as this front/environment along with precip development push east towards the CWA later this afternoon. Now, while the highest instability and higher threat for more robust development is situated just to the west of the CWA at this time, areas along and west of I-39 in northern Illinois still have a threat for this stronger development before MLCAPE weakens and CIN increases. Guidance has struggle to catch up on trends, and think its also still struggling to the most eastward extent. This will occur, while bulk shear will be more than sufficient for organized development and while low level flow continues to increase. Showers/thunderstorms will likely reach the I-39 corridor in the 5-7 PM CST time frame, with the highest threat of strong to severe thunderstorms along this corridor and with the main hazards damaging winds. This is especially as the low level flow increases, strong flow that is just right above the surface. Although the main hazards would be strong damaging winds, could not rule out an isolated tornado threat. This threat should be higher to the west, but cannot rule out this threat reaching the CWA. As these showers/storms push further to the east in the evening, intensity of any storms should diminish. However, will need to monitor for a continued threat further to the east as this convection moves into northeast Illinois and northwest Indiana. Southerly winds/gusts have continued to increase this afternoon, and will likely continue this trend this afternoon into the evening. Gusts of 45-50 MPH will remain a possibility but with FROPA later this evening, could see a slight quick increase. Also, outside of the thunderstorm threat, high wind gusts will be possible with any shower. Rodriguez && .LONG TERM... 223 PM CST Tuesday night through Monday... Main message for the extended is colder and mainly dry. Blustery winds continue through Wednesday, although winds will not be as gusty as they were today (Monday). A clipper system could bring a chance of snow Friday evening/Saturday. The surface low driving the strong winds will continue northeast to James Bay, but gusty winds will continue thanks to a tight pressure gradient. 35 MPH gusts are expected Tuesday night followed by gusts to 25-30 MPH Wednesday. Low temperatures Wednesday morning will be in the low 20s while wind chills will be around +10 or in the single digits above zero. Highs Wednesday will be in the low 30s, but wind chills will make it feel around 20 degrees. An upper level vorticity streamer may force flurries south of I-80 Wednesday morning, but no impact is expected. Cold and dry conditions continue under the upper level trough through late week. A clipper system rotates around the trough and may bring snow to the region Friday evening/Saturday. A punch of colder air may accompany the snow with forecast 925mb temps of -12 to -10 C. This could result in colder temperatures than currently forecast Saturday. Models then show a slight warming trend early next week. JEE && .AVIATION... For the 00Z TAFs... Southerly winds (190-200) should continue ahead of the front this evening with prevailing gusts in the 30-38kt range expected. Narrow line of SHRA/TSRA and associated strong cold front currently approaching the MS River will move across the terminals this evening. Current timing suggests 04-05z at ORD/MDW, but given the potential for some additional development ahead of the line, maintained a 2 hour TEMPO window. Given the strong wind fields, even a moderately heavy shower could mix 40kt+ gusts to the sfc. Expect the current TSRA activity to weaken as it moves across northern IL, but still some robust SHRA and ISLD TSRA look are expected. Behind the front, winds will remain strong and gusty from the west, with gusts near or above 30kt likely overnight and through the day Tuesday. Guidance suggests that skies should clear out behind the front, though will need to monitor an area of MVFR CIGS over western IA for potential of those clipping the terminals late tonight/early Tues AM. - Izzi && .MARINE... 223 PM CST Gale warnings remain in effect, and the only adjustment was extending the open water gale warning into mid Wednesday morning. The strong low over the upper Mississippi Valley will continue to deepen as it moves to central Ontario by mid-day Tuesday. The low`s cold front will push across the lake after midnight, and storm force gusts are expected over the northern end of the lake. I did not have enough confidence in persistent storm force winds to go with a storm force warning. The low will continue northeast, and west gales will continue into Wednesday morning. West to northwest winds 20-30 kt persist through Friday. A surface low/cold front turn winds north late Friday night into Saturday morning. A brief period of gales is possible, although confidence is low. A weak surface ridge passes over the region Saturday night quickly followed by another low and cold front Sunday night. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...Wind Advisory...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011- ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023- ILZ032-ILZ033-ILZ039 until 6 AM Tuesday. IN...Wind Advisory...INZ001-INZ002-INZ010-INZ011-INZ019 until 6 AM Tuesday. LM...Gale Warning...nearshore waters until 6 AM Wednesday. Gale Warning...LMZ777-LMZ779 until 9 AM Wednesday. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Please see the 05/00Z aviation forecast discussion below.

&& .AVIATION... VFR conditions are forecast. A cold front will slide southward across west Texas and southeastern New Mexico overnight, with initial FROPA expected at KHOB around 05/06Z with the remainder of the terminals in the next 2-3 hours. Light and mostly variable winds this evening will become northeasterly and gust to near 30kts behind this front. Winds will begin to lay down during the morning hours, with 10-12 kts forecast after 05/18Z. Clouds will begin to thicken and ceilings lowering after 06/00Z. && .PREV DISCUSSION... /issued 245 PM CST Mon Dec 4 2017/ DISCUSSION... One last warm day in West Texas and Southeast New Mexico, w/temps already set to top out close to 20F above-normal before the afternoon is out. Unfortunately, this will come to an end overnight as a strong cold front backdoors into the region, courtesy of an upper trough currently moving thru the upper midwest as per WV imagery. Latest sfc analysis has the front in the Panhandles, w/hi-res models putting fropa at KMAF ~ 04Z. This will take temps well-below normal thru at least Friday. In the meantime, WV imagery shows a secondary trough developing over the west coast, which is set to settle se into the SW CONUS by 12Z Wed. As it does so, an upper jet will move north of the area, putting the FA under the RR quadrant by Tuesday night. Isentropic upglide is forecast to begin after 00Z Wed...about 12 hrs earlier than models were forecasting 24 hrs ago. The frontal AMS is pretty shallow at first, w/precip expected to begin as all RA. However, as the night wears on, the warm nose diminishes N-S, w/a changeover to SN across the nrn-tier zones, a wintry mix further south, and a RA/FZRA mix across the Davis Mtns/lwr Trans Pecos. As temps warm a little Wed, frozen precip will try to change back over to RA, but forecast soundings go south of the freezing lvl from near the sfc all the way up by 00Z Thu, for a changeover to all SN everywhere but the Rio Grande Valley and Big Bend Wed night. The above scenario comes w/several caveats. NAM Forecast soundings lean toward a wintry mix of precip, and dry things out rather early, whereas the GFS saturates the column faster and transitions everything to snow faster than the NAM, and also is slower to dry things out. Models tend to scour out the PBL rather early in these events, so the slower solutions seem favorable. If the NAM pans out, precip types will be hard to nail down, as forecast soundings ride the 0F isotherm up thru the warm nose. If reality favors the GFS, SN will be favored. Attm, confidence is mediocre. Higher QPFs look to be in the south, but w/antecedent ground temps where they are, significant wintry precip accumulations are not expected in the short term. The timing of the changeover to wintry precip is too far out for a watch attm, and we`ll continue to handle this in the HWO and SPS. Precip should taper off in the south Thursday night, w/dry conditions thereafter. Temps recover to above-normal by Saturday. && .PRELIMINARY POINT TEMPS/POPS... Big Spring 39 47 34 45 / 0 0 20 50 Carlsbad 39 46 32 42 / 0 0 20 50 Dryden 50 56 38 46 / 0 10 20 70 Fort Stockton 44 49 35 39 / 0 0 30 70 Guadalupe Pass 39 42 29 37 / 0 0 30 60 Hobbs 37 44 31 44 / 0 0 20 40 Marfa 37 54 29 43 / 0 0 30 70 Midland Intl Airport 41 48 35 44 / 0 0 20 60 Odessa 41 48 34 43 / 0 0 20 60 Wink 39 51 33 41 / 0 0 30 60 && .MAF WATCHES/WARNINGS/ADVISORIES... NM...None. TX...None. && $$ 70/84/70
Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
934 PM CST Mon Dec 4 2017 .UPDATE... Issued at 934 PM CST Mon Dec 4 2017 Blizzard conditions are occurring along the MN river this evening. New Ulm recently gusted to 58 mph with 1/4 mile visibility. There have been several other reports of 50 mph gusts over the past couple hours. The snow is not expected to last long enough to warrant an upgrade to a Blizzard Warning, with the back edge of the snow already approaching Redwood Falls. A well developed deformation band of snow is rotating eastward across Minnesota. Increased snow totals across eastern MN and western WI per latest trends. The HRRR has been advertising greater than 4 inches from the metro northeastward, which isn`t impossible, but it would need to snow faster than an inch per hour in order for that to occur. The better bet is for 2 to 3 inches. Travel conditions are treacherous where temperatures have fallen below freezing. Deteriorating road conditions can be expected to spread eastward as the evening progresses. && .SHORT TERM...(This evening through Tuesday) Issued at 313 PM CST Mon Dec 4 2017 The main change to the short term involved attempting to capture the potential for an enhanced (narrow) band of snowfall over central MN where favorable dendritic growth zone intersects impressive omega as an impressive pocket of PV advection lifts across east central MN and west central WI this evening. Did increase snowfall ratios as well. All these factors considered led to most locations west of I-35 (with the exception of along I-90) having the potential for 2-3+ inches of snow falling in a relatively short period of time, creating reduced visibilities and slippery roads. Therefore transitioned much of central/west central MN and a small portion of west central WI that was in a wind advisory to a winter weather better capture all anticipated impacts. We also look to have some upright instability so thundersnow will be possible this evening as well, which could also enhance amounts. .LONG TERM...(Tuesday night through Monday) Issued at 313 PM CST Mon Dec 4 2017 Very few changes were made in the long term forecast period. Northerly flow will prevail, which will mean the door will open for cold air to move in from Canada. Temperatures through the weekend will generally range around 5-10 degrees below normal. Occasional shortwaves will clip the region, but little to no attendant moisture and their quick- moving nature will limit snowfall potential. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 614 PM CST Mon Dec 4 2017 Generally IFR conditions are in place, with rain advancing northeast from south central MN and snow across western MN. The precip will transition to snow from west to east this evening with periods of moderate snow (1/2SM vis) possible. The snow should end about 4 or 5 hours after its onset. Strong northwest winds expected tonight with some gusts to 45 kts possible, especially across western MN. KMSP...Rain will become steady within the hour, then transition to snow between 02-03Z. Visibility may drop to LIFR levels and accumulations of 1 to 3 inches are expected. /OUTLOOK FOR KMSP/ Wed...VFR. Wind NW 10-15G25kts. Thu...VFR. MVFR possible late with Chc -SN.Wind NW 5-10kts. Fri...VFR. MVFR possible early with Slgt Chc -SN. Wind NW 5-10kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...Winter Weather Advisory until 4 AM CST Tuesday for WIZ014>016- 023. Wind Advisory until 6 AM CST Tuesday for WIZ024>028. MN...Winter Weather Advisory until 4 AM CST Tuesday for MNZ043>045- 049>053-057>063-065>070-073>077-082>084-091-092. Winter Weather Advisory until midnight CST tonight for MNZ041- 042-048. Winter Storm Warning until midnight CST tonight for MNZ047- 054>056-064. Wind Advisory until 4 AM CST Tuesday for MNZ078-085-093. && $$ UPDATE...BORGHOFF SHORT TERM...LS LONG TERM...LS AVIATION...BORGHOFF
Area Forecast Discussion
National Weather Service Paducah KY
859 PM CST Mon Dec 4 2017 .UPDATE... Issued at 859 PM CST Mon Dec 4 2017 Updated the public forecast to delay the arrival of the convective line by an hour or two. Radar trends through the evening have been steadily downward and lightning activity has also been dwindling. Given the strength of the wind field, especially in the low- levels, a few gusts up to 40 mph will be possible, but severe weather is unlikely. Of course gusts up to 35 mph will continue to be possible ahead of the line. && .SHORT TERM...(Tonight through Wednesday night) Issued at 1253 PM CST Mon Dec 4 2017 Early this afternoon, a deep surface cyclone was over southern MN with a trailing cold front extending south into the southern Plains, still well to our west. Sharp s/wv energy was moving across the northern Plains, with a nice fetch of moisture seen on wvapor moving NE along a 75-90 kt upper level jet. Radar showed an increase in light showers over the past hour. Members of the HREF and HRRR show an uptick in scattered convective activity this afternoon. The activity should head NE 40-45 mph, with isolated thunder possible. The models depict a lull after this initial area of WAA convection driven by weak mid level support and low level moist transport. Gusty south winds to continue. Focus for convection tonight will be along the aforementioned cold front, that will move across the area. Continued with categorical 100 PoPs for showers and scattered thunderstorms. PWAT`s will be unseasonably high as the front moves through. So some decent and much needed rain is forecast. The chance of strong and isolated severe will stay to our west. Even with a decent low level jet, the low level lapse rates are not conducive to downward momentum. Just gusty surface gradient winds ahead of and behind the front. The precipitation will move out quickly from west KY Tuesday morning, with dry weather from Tuesday afternoon through Wednesday night, as a surface ridge axis moves southeast across the area, with dry NW flow aloft forecast. It will be colder behind the front, but not too far from norms. Colder air arrives later in the week. Stayed close to persistence and MOS for temps. Decent model agreement overall in the short term. Precip/PoP trends will be derived from the HRRR, and members that make up the HREF, and some NAM incorporation. .LONG TERM...(Thursday through Monday) Issued at 1253 PM CST Mon Dec 4 2017 Confidence remains high that a high amplitude flow pattern will prevail through the long term. The overall pattern will be a strong mid level ridge over the west U.S., and deep trof over the east 1/2 of the nation. The mean trof axis positions are similar longitudinally to 24 hours ago, perhaps slightly slower per the latest ensemble mean solutions. Significant negative anomalies continue to be seen with this trof over our area. This will result in below normal temperatures, as much as 5 to 15 degrees, and unsettled weather, as impulses head SSE, bottom out in the base of the trof and then head on east. Despite the very low heights aloft, surface pressures are not terribly high, negative anomalies minimal. It continues to look dry Thursday. The models for two days now show a lead wave that will move across the area late Thursday into Thursday night then dampen. The uncertainty lies with forecast moisture. The GFS is persistent suggesting some very light snow showers or flurries may move across the area. However the EC and CMC solutions remain dry. Sometimes the EC and CMC are too conservative in this regard. So we prefer to keep a slight chance 20 PoP going. The models depict a lull Friday. A consistent signal remains for Friday night. Another s/wv will move SE across the area resulting in additional h5 height falls, and greater moisture. There is generally agreement across the board, that light snow will accompany this system, with the best chances across the NW 3/4 of the area. Bear in mind this is a late day 5 into early day 6 forecast, and the details may change. For now, conservative and appropriate wording is we may see some snow, and possibly light accumulations should the signal remain. Adjustments in timing and such will continue to be made over the next few days. Will there be any impacts? Way too early to tell. Other than maybe some lingering light snow showers or flurries early Saturday SW Indiana and KY Pennyrile, dry weather on through Sunday and most of Monday. Temperatures will moderate Sunday into Monday as the mean mid level trof axis moves on east. && .AVIATION... Issued at 536 PM CST Mon Dec 4 2017 Little variation in timing and lowering of ceilings and visibilities from VFR to MVFR (with locally brief IFR visibilities possible) from 18z Monday WFO PAH TAF issuance. Current pre- frontal and main cold front convection and cloud cover following closely to the NAM-WRF model guidance. May have trended in the wrong direction, but returned ceilings and visibilities back to VFR category between 7z and 10z Tuesday as frontal boundary moves east of the WFO PAH TAF sites. Will monitor. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ UPDATE...DRS AVIATION...Smith