Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/12/16

Area Forecast Discussion
National Weather Service Wakefield VA
831 PM EST Sun Dec 11 2016 .SYNOPSIS... A warm front lifts through the Mid Atlantic overnight as low pressure moves into the Great Lakes. The trailing cold front crosses the region late Monday and stalls across the Southeast through Wednesday as high pressure builds north of the region. A strong cold front crosses the area Wednesday and ushers in Canadian high pressure for Thursday and Friday. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... The current surface analysis places 1032+mb sfc high pressure now offshore of the Mid-Atlantic coast. To the south, coastal front/warm front noted moving inland along the Carolina coast, to near KHSE at 01z. Early evening GOES IR/WV sat imagery showing a vigorous trough digging across the Upper Midwest. Have noted increasing/lowering clouds over the past few hours, which has halted the lowering temp trend over most of the area. The trough pushes into the Great Lakes tonight with the mid- level ridge axis sliding offshore. This will allow for the coastal/warm front to lift NNW through the Mid-Atlantic overnight. Rain chances are low through early this morning, and given dry air still aloft, would be nothing more than some patchy drizzle or very light rain. After 09z/4am, Rain chances increase over the piedmont as better moisture/forcing arrives from the west. Again expect any pcpn to be light across the SE coast, patchy dz or light rain. Farther inland, rather narrow/shallow layer of overrunning moisture will result in more areas of light rainfall to move across the NW half of the area...with these showers gradually weakening into later Monday morning. Becoming damp and chilly from the interior coastal plain to the Piedmont. Temps will rise late tonight, but will be slower to rise inland as the cool air will be stubborn to erode in the cool air wedge inland. Temperatures currently in the mid 30s to low 40s reach the low to mid 40s inland late...low/mid 50s along the immediate coast by 12z Monday. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... A potent nrn stream shortwave trough tracks from the Ern Great Lakes Monday morning to the Saint Lawrence Valley, which will push the associated cold front into the area Monday aftn. Srn stream moisture will pass across the region Monday morning. Forecast PoPs are highest across the north in closer proximity to the best forcing for ascent. PoPs diminish during the late morning and aftn from west-east as drier air pushing into the region erodes any lingering showers. Deep-layered w-sw flow will limit QPF, which at this time is forecast to be aob 0.3" for most of the area, with slightly higher amounts possible over the MD Ern Shore. Milder with highs ranging from the mid 50s n/nw, to the low/mid 60s se. The cold front pushes south of the region Monday night and stalls across the Southeast into Tuesday as it becomes aligned parallel to strong zonal flow aloft. A slight chc PoP continues for se portions during the evening. Otherwise, cooler drier air will filter in from the nw. Clouds initially decrease from nw-se Monday night, before mid/high clouds likely increase from west-east ahead of a shortwave trough tracking across the Deep South. Lows range from the low/mid 30s n/nw to the mid 40s se. This shortwave tracks across the Southeast Tuesday. 11/12z data has suppressed this system, so only a 20% PoP will be maintained for extreme se VA and much of ne NC, with ~30% PoP adjacent to the Albemarle Sound. Partly sunny north to mostly cloudy south with highs ranging from the upper 40s north to low/mid 50s south. An active srn stream continues Tuesday night into Wednesday as the front remains stalled to the south of the area, and high pressure remains to the north. The high should be the dominant feature, with cool/dry air keeping much of the rain potential to the south. PoPs will generally be 20-30% for far srn VA into ne NC, with PoPs < 15% across the nrn 2/3rds of the area. Generally partly cloudy north to mostly cloudy south. Lows Tuesday night range from the low/mid 30s north to the upper 30s south, followed by highs Wednesday in the upper 40s north, to low/mid 50s south. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... A broad upper level trough crossing nrn Ontario into the Great Lakes Region finally digs through the Mid Atlantic Region Wed night...pushing a weak coastal trough (and its associated precip) out to sea. Precipitation on the back edge may transition over to snow before coming to an end, however little to no accumulations are anticipated at this time. As the upper trough drops into the region Wed night, another arctic airmass is expected to blast into the area late Wed night...especially as the winds shift to the nw and increase. Wind speeds along the immediate coast should reach 20-25 mph on Thu with gusts of 30-35 mph...likely resulting in wind chills of 15-25F during Thu morning. Breezy conditions along the coast will persist through Fri morning before improving. Canadian high pressure settles over the Mid Atlantic Region Fri/Fri night and then slides out to sea on Sat. As the sfc ridge moves away from the coast, warm air advection processes will very slowly erode the remaining cold air wedge. Meanwhile, sfc low pressure pushes out of the Central Plains Fri night and tracks into the Great Lakes/srn Ontario on Sat. The combination of a warm front lifting through the Mid Atlantic Region and progressive sw flow ahead of the approaching cold front could easily pull Gulf moisture along the Appalachians and cause overrunning precip to develop in west and northwest counties of the forecast area. Mixed precip-type likely an issue at the onset Sat morning within the aforementioned counties before precip changes to all rain by late morning. However, there is too much uncertainty regarding timing and placement of moisture this far out in the forecast to define anything beyond a basic rain or snow precip- type. Will keep a close eye on this feature and enhance wording/concern as warranted. Temperatures typically slower to fall in strong arctic scenarios versus dewpoints, which tend to plummet first. Lows Wed night in the mid-upper 20s nw to low-mid 30s se. Arctic airmass arrives in full force for Thu and highs will struggle to reach the mid-upper 30s most areas (lower 40s far se coastal areas) with wind chills in the 20s more areas (lower 30s far se coastal areas). Coldest night of the season is anticipated for Thu night with lows in the mid teens nw to lower 20s (mid 20s beaches), which is about 1 std dev below normal. High temps even colder on Fri (low-mid 30s most areas /mid-upper 30s far se) as high pressure settles directly overhead. This is roughly 1.5-1.75 std dev below normal. Sfc ridge axis shifts ewd off the coast Fri night. Overnight temps rebound by a few degrees with increasing clouds from the southwest, however the area will stay well wedged within the arctic airmass. Lows Fri night in the mid-upper 20s (lower 30s far se coastal areas). Temps slow to warm Sat morning but should warm quickly in the aftn as a cold front approaches the region and winds become more south and breezy. Highs Sat 45-50F nw to mid- upper 50s se). Warmer Sat night with lows in the upper 30s to lower 40s nw to mid 40s to lower 50s se. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... VFR conditions prevailed at the TAF sites early Sunday evening but moisture will spread northeast as a warm front lifts through the area. This will result in lowering conditions and periods of light rain and drizzle Monday morning. A cold front will cross the region late in the day Monday. Ceilings of 4 to 7 Kft were developing over southern Virginia as of 00Z. These ceilings will spread northeast this evening and then lower to MVFR/IFR in the morning. Rain and drizzle will develop Monday morning. Conditions slowly improve from the west Monday afternoon. A south to southwest low level jet will produce 40 to 45 knots winds at 2k feet Monday morning and periods of LLWS is indicated in the forecast. Outlook: The cold front stalls over the Carolinas and dry weather is expected Monday night and Tuesday. There will be the possibility of MVFR or IFR conditions Tuesday morning. Otherwise mainly VFR is expected into WEdnesday. There will be a chance for precipitation late Wednesday and Wednesday night associated with a strong cold front. Drier conditions return Thursday through Friday. && .MARINE... 7 PM update...Winds are increasing a little sooner than expected especially along the western side of the Bay. Blended the forecast with HRRR for the first the first six hours of the forecast and started the SCA 3 hours 10 PM. Previous discussion... SCA flags added for mouth of James River and Currituck Sound after midnight tonight into Mon morning. Sfc pressure gradient tightens in response to a weak coastal trough developing ahead of a low pressure system tracking across the Great Lakes tonight and across New England on Mon. Low-end s-sw SCA winds of 15-20kt (gusts 25-30kt Bay/Ocean) are expected to develop after midnight tonight and persist into Mon morning before diminishing. Seas build to 3-5ft after midnight and will be slower to subside below 5ft for coastal waters north of Cape Charles Light until late Mon aftn. Waves building to 2-3ft. The cold front crosses the waters Mon evening with scattered showers tapering off quickly from west to east. The airmass behind the front is not much cooler than pre-frontal antecedent conditions and n winds are expected to remain aob 15kt all waters late Mon night. Weak sfc high pressure moves quickly into the region on Tue with more coastal troughing developing off the Southeast Coast Tue night/Wed. Meanwhile, broad upper level troughing across nrn Ontario into the Great Lakes Region should keep the latest coastal system/trough generally suppressed along/south of the VA/NC border during this time. The combination of these features will result in light n-ne winds aob 10kt in this timeframe. Seas 2-3ft/waves 1-2ft. The upper trough finally digs through the Mid Atlantic Region Wed night...pushing the weak coastal trough out to sea and bringing another arctic blast to the area. Winds shift to the nw late Wed night and increase to solid SCA conditions (15-25kt), which will persist over the waters through Fri morning before conditions improve. Seas build to 3-5ft by Thu morning/waves build to 3ft with periods of 4ft waves possible Thu/Thu night. Canadian high pressure settles over the waters on Fri and SCA conditions should fully abate by Fri aftn/early evening. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 1 PM EST Monday for ANZ630>634. Small Craft Advisory until 8 AM EST Monday for ANZ638. Small Craft Advisory until 4 PM EST Monday for ANZ650-652-654. Small Craft Advisory until 10 AM EST Monday for ANZ656-658. && $$ SYNOPSIS...AJZ/MPR NEAR TERM...AJZ/MAM SHORT TERM...AJZ/MPR LONG TERM...BMD AVIATION...AJB/LSA MARINE...BMD/LSA
Area Forecast Discussion
National Weather Service Gaylord MI
909 PM EST Sun Dec 11 2016 .UPDATE... Issued at 909 PM EST Sun Dec 11 2016 Mid level short wave trough axis is advancing into the midwest this evening with the main short wave center pushing into Wisconsin, and a secondary circulation punching across Iowa. Attending deepening surface low analyzed over eastern Wisconsin lifting northeastward into lower Michigan and trailing cold front stretching down through Missouri. Nice moisture feed up into the lower lakes region, combined with decent mid level frontogenesis and upper level jet divergence has lead to a prolonged period of heavier snowfall through the day, stretching from the midwest into lower Michigan. Heaviest of the snow has fallen (and continues to fall) from Chicago across southern lower Michigan with totals up near 10 inches in a few spots. Lesser amounts up across northern Michigan with >4 inches south of M-72, trailing off to under an inch in the tip of the mitt and eastern upper Michigan. Axis of widespread snowfall will continue to peel off to the east as the mid level short wave trough presses into the western Great Lakes by morning, and surface low pressure pivots up into northern Michigan. Snowfall has already largely ended for the N/W part of the CWA. But E/SE parts of the CWA will continue to see widespread snowfall through around midnight or so before ending, and perhaps an inch or two of additional snow accumulations. Only exception, one can just make out sneaky SE flow enhanced lake bands on radar streaming into the far eastern parts of eastern upper MI around Drummond Island and De Tour. That will continue for several more hours until low level SE flow finally breaks down. Thus have beefed up localized snow accumulations for that area into the 3 to 5 inch range. Overnight, upstream mid level short wave and associated "wrap around" deformation enhancement will be sliding through northern Michigan late tonight through Monday morning. This will bring another period of lake enhanced snow showers back into parts of eastern upper and northwest lower Michigan as winds swing back around to the W/NW. May pick up another inch or two through Monday from that. Headlines: I may be able to trim out some of the counties in northern lower Michigan as snow has already ended. Will keep eastern upper Michigan in the advisory for now given the lake enhanced bands, as well as the E/SE counties. && .NEAR TERM...(Tonight) Issued at 344 PM EST Sun Dec 11 2016 ...Widespread snow winds down tonight... High Impact Weather Potential...Accumulating snow will continue into this evening. Pattern Synopsis/Forecast...Surface low will travel from near the WI/IL border to eastern Lake Huron by Monday morning. Meanwhile a strong shortwave/vort max will cut across northern Wisconsin and Michigan, supporting a cyclonic circulation over northern Lake Michigan that will lead to lake enhanced snow bands late tonight. Primary Forecast Concerns...Widespread light snow will be ongoing into early evening across northern Michigan as weakening isentropic and frontogenetic lift continue but become more diffuse. DGZ depth will be shrinking as we head into the late afternoon and evening with the best omega found further aloft. So, expect snowfall rates to continue diminishing over the next several hours with just a few lingering pockets of more moderate snowfall. As the surface low lifts towards northern MI this evening, models show the snow tapering off first across northern Lower. Moisture currently over southern WI and northern IL will continue to stream generally northeastward, placing our southeastern counties under the remaining snowfall from this event for the longest duration. This will lead to perhaps another 2-3 inches near Saginaw Bay before the snow finally winds down there. Elsewhere expect generally another inch or two through this evening, though locally higher amounts from lake enhancement are likely across eastern Chippewa County. The snow will clear out of our eastern counties early Monday morning as the cold front sweeps eastward. However, a potent shortwave clipping the Upper Great Lakes will support the development of a compact surface low over northern Lake Michigan after midnight. Both synoptic and hi-res models show this, though the hi-res models obviously capture potential lake enhanced snow bands in better detail. The NMM, ARW, and HRRR all show the bands coming ashore between Leelanau and Manistee counties between 06-12Z Monday, but they should be fairly narrow and orient themselves parallel to the coast as they wrap around the low. Thus, not expecting them to produce prolonged snowfall for any particular location. Will be trimming back the Winter Weather Advisory to 09Z Monday as the bulk of the accumulating snow will be winding down and moving out of the area early Monday. && .SHORT TERM...(Monday through Wednesday) Issued at 344 PM EST Sun Dec 11 2016 ...Arctic Air Arrives Midweek... High Impact Weather Potential: Burst of snow and gusty winds possible with arctic boundary Monday night into Tuesday morning. More lake snows in the traditional snow belts Wednesday. Pattern Synopsis/Forecast: Current snow-producing system will exit quickly stage right Monday morning, with all attention then directed toward deep troughing/attendant very cold core temperature anomolies dropping south across northern Canada (-20F surface temperatures!). This troughing will continue to dig southeast over the coming days, the core of which passes across northern Ontario during the day Wednesday. Attendant arctic front crosses the northern Lakes early Tuesday, with bitter cold air quickly to follow it for the midweek period. Primary forecast concerns: Plenty! Addressing lingering lake enhanced snow concerns Monday, lake enhanced snow potential Monday night into Tuesday morning, and downward temperature trends and additional lake snows into Wednesday. Details: Lingering lake effect Monday in those traditional snow belt locations as vort max and brief surge of cooler air follow departing system. Attention then turns to rapidly approaching arctic front Monday night. Multiple forecast issues with this front, with initial focus on brief window of southwest flow lake enhancement impacting areas of far northwest lower and up into the Straits region. Time of favorable wind direction is a short one, but strong forcing tied to frontal passage and good moisture profiles support at least a window of some very impressive snowfall rates. Front passes quickly Tuesday morning, with gusty west winds in its wake. These winds will usher in a progressively colder airmass, with temperatures likely falling through the teens during the afternoon (wind chill values several degrees colder!). Simple magnitude of caa will likely result in some lake snows in favored areas, although aggressive drying and limited inversion heights should keep snow intensity in check. However, even with limited new snow, those gusty winds will likely result in plenty of blowing and drifting and some treacherous driving conditions. West flow lake effect continues Tuesday night and Wednesday, likely steadily increasing in organization and intensity as synoptic moisture contribution increases. While upstream temperatures look cold enough to keep fluff producing DGZ near the surface, would expect lake modification to be extreme, likely "warming" the profiles enough to place the DGZ within the convective cloud layer. This, combined with simple persistence of the wind direction, will likely result in several inches of snow across northwest lower and for areas near Whitefish Point/Paradise up in eastern upper Michigan. Add in those gusty west winds, and may see some whiteout conditions in open exposed areas. Perhaps bigger story will be the temperatures, with highs struggling into the lower teens away from the big waters and wind chill values several degrees below zero. Can definitely see the need for some winter type headlines as this period draws near. Will continue to use our latest hazardous weather products as avenues to express this potential high impact period of weather. .LONG TERM...(Wednesday night through Sunday) Issued at 344 PM EST Sun Dec 11 2016 A very active and wintry pattern to continue across the Great Lakes through the period. At upper levels, a sharp 500mb trough over the region Thursday will exit east Friday, before a second 500mb trough digs into the the northern Plains and Great Lakes for the weekend. 850mb temps in this pattern will be between -20c and -24c...warming only briefing to around -10c Friday in advance of approaching second 500mb trough. This will keep afternoon highs well below normal, in the teens, through hte period. Periods of snow will continue across northern Michigan through the a storm system exits east Thursday while a second system pushes across the Great Lakes during the weekend. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 742 PM EST Sun Dec 11 2016 Widespread snowfall will diminish/end from W-E as we go through the evening hours bringing a return to VFR vsbys. CIGS will continue to bounce from high MVFR to low VFR overnight. But another smaller batch of snow showers will rotate through the region late overnight through Monday morning, particularly impacting NW lower Michigan. && .MARINE... Issued at 344 PM EST Sun Dec 11 2016 Gusty southeast winds become west and increase in speed later tonight into Monday as low pressure crosses the region. SCA conditions will be experienced on some nearshore waters. Conditions only worsen Tuesday night through Thursday as very gusty west to northwest winds spread across all the big waters. Gale conditions are looking increasingly likely during this period. && .APX WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY until 4 AM EST Monday for MIZ008-015>036- 041-042. LH...NONE. LM...SMALL CRAFT ADVISORY from midnight tonight to noon EST Monday for LMZ346. LS...NONE. && $$ UPDATE...TBA NEAR TERM...MEK SHORT TERM...MSB LONG TERM...SWR AVIATION...TBA MARINE...MEK
Area Forecast Discussion
National Weather Service Charleston SC
1027 PM EST Sun Dec 11 2016 .SYNOPSIS... High pressure will prevail until the passage of a coastal trough tonight. A cold front will move into the area Monday night before stalling and then likely lingering through mid week. The front will push offshore Wednesday night, followed by colder high pressure for late week. Another coastal trough and cold front may affect the region by next weekend, which would bring more unsettled weather. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Late this evening: Well, the showers that developed and pushed onshore across portions of the Tri-County earlier were surprisingly heavy. That activity has now diminished and moved off to the northeast while other showers are developing within the trough offshore. Have updated PoP`s to increase values over water and land through the early morning hours as this is supported well by the HRRR and RAP. No change in thinking with regard to the fog threat overnight. It is still complicated and an increase in coverage of precipitation would only add to the complexity. Previous discussion follows below. Early this evening: The main forecast issue for the overnight revolves around fog potential. Once the coastal trough gets north of the area, a mild and moist southerly flow will prevail into Monday morning. Moisture is nicely concentrated in the lower levels of the atmosphere and the overall flow will be relatively light. It is certainly not a traditional radiation fog setup with plenty of stratocumulus already in the vicinity and elevated winds just above the surface. In fact, a perusal of model soundings shows 15-20 knots of flow in the 500-1000 foot layer and this is supported by the winds from the 00z RAOB. So, the low level wind setup is certainly not ideal for widespread fog or even dense fog. However, model soundings show a nice stratus build down signature, which may allow fog to persist despite the low level flow. Another complication is the fact that the suite of models show varying degrees of shower activity increasing across the area late tonight. The forecast continues to feature patchy fog everywhere and areas of fog mainly along and west of I-95, similar to the previous forecast. Certainly not enough confidence to increase fog wording or entertain the idea of a dense fog advisory at this time. No other significant changes to the forecast at this time. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Overview...A much more unsettled pattern through mid week. Higher chances for rainfall with temperatures starting off above normal Monday, then near to slightly below normal Tuesday and Wednesday. Monday and Monday night...A weak cold front will be approaching the area from the west. Moisture and forcing is limited with this front, and have continued with low end chance to slight chance pops, highest over the west. Expect mostly cloudy skies, but with southwest low level flow, temperatures will rebound into the lower 70s north to mid 70s south. Monday night...models show the front stalling over the forecast area, but exact location differs between the models, which will impact temperatures. For now, have gone with the front stalling over the central forecast area with lows in the mid 50s north to the upper 50s around 60 south. Another weak surface wave begins to approach from the southwest and sets up an overrunning situation for later at night. Again, models differ on timing on when precip would begin. Have gradually increased pops from west/southwest to east/northeast through the night ending in the high end chance level late. Guidance also showing the potential for low ceilings and fog, especially SC zones. Have added patchy fog entire area for now. Have also kept patchy sea fog near the coast. Tuesday and Tuesday night...Looks like a weak surface low will ride across the stalled front from the southwest, which should result in widespread light rain across the area. Have increased pops to low end likely to high end chance for now. Hung on to some patchy sea fog near the coast through early afternoon given southwest winds advecting relatively warm/moist air over the cooler shelf waters. Temperatures will be tricky and dependent on where front sets up. Currently have a large range with low 60s extreme north to lower 70s extreme south. Tuesday night...Chances for light rain will continue, but models do show the potential for lower pops during this period with one surface low lifting northeast of the area and the next one forming over the northern Gulf of Mexico. Lows in the lower 50s north to the upper 50s south, but will be very dependent on where the stalled front is located. Wednesday...Another weak surface wave is shown by all models to move back over the stalled front from southwest to northeast. Again, expect this to bring widespread light rain if it verifies. Given uncertainty this far out, have kept low end likely to high end chance pops. Temperatures will continue to be difficult, with the potential for a big range from north to south. Have highs in the lower 60s north to around 70 south. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... An approaching upper trough should push the stationary front offshore Wednesday night with colder high pressure to build in from the north through Friday. Highs Friday may struggle to 50 degrees for at least the interior portions of the forecast area toward the Pee Dee/Midlands/CSRA. Another coastal trough will likely develop later Friday and could bring some showers especially Friday night/Saturday across SC. Rain chances should then increase either late Saturday night or Sunday as a cold front begins to affect the area. After near normal temperatures Thursday and below normal temperatures Friday, temperatures should be above normal for the weekend. && .AVIATION /04Z MONDAY THROUGH FRIDAY/... A very tricky next 12 hours. There is broad agreement that some combination of ceilings/visibilities will support MVFR and eventually IFR flight categories. However, confidence is still low regarding the timing and exact impacts at KCHS and KSAV. This looks like a potential stratus build down event which could overcome some of the ingredients missing for a dense fog event. Model guidance is quite consistent that MVFR conditions will begin around or just after 06z at both sites, with IFR a couple of hours later. Overall confidence is higher at KSAV which has a lesser chance of showers late tonight and in an area with weaker flow. The forecast now features IFR conditions at both sites, starting earlier and lasting longer at KSAV. Improvement to MVFR and then VFR is expected by late morning and early afternoon. Extended Aviation Outlook: Through Wednesday...Expect at least periods of flight restrictions, mainly in the form of lower ceilings, with a stalled front likely between KCHS and KSAV as weak surface lows move along the front from southwest to northeast. By Friday, another weak coastal trough may develop, which depending on moisture return, could bring the return of some flight restrictions, but confidence low out that far into the forecast. && .MARINE... Tonight: The persistent coastal through will gradually push north tonight with south winds eventually prevailing across the local marine area. Winds will pick up east of the cooler shelf waters with speeds reaching as high as 15-20 kt across the Georgia offshore waters and the far eastern portions of the Charleston County waters. Lower speeds will occur across the remaining nearshore waters and Charleston Harbor. The current thinking is that sea/marine fog development could wait until land based fog and stratus develops and then bleeds into the coastal waters early Monday morning. Do not anticipate widespread dense fog development at this time, but this will have to be watched. Seas will average 2-3 ft nearshore waters with 3-4 ft Charleston County waters and 4-5 ft Georgia offshore waters. Monday through Wednesday...No highlights expected at this time. A weak cold front is expected to stall over the waters later Monday through Wednesday. Southwest winds are expected to increase to 15-20 kts, especially 20 nm or more offshore ahead of the front Monday afternoon. Monday night through Wednesday, this front is expected to stall in a west-east orientation across the central portion of the waters. Periods of weak surface low systems are shown by the models to move across this front brining scattered shower/light rain periodically through the period. At least patchy sea fog is possible Monday through Monday afternoon with near shore southwest winds advecting warmer/more moist air over the cooler shelf waters. Wednesday night through Friday...A stronger cold front moves through the waters Wednesday night. Behind the front, strong cold advection will bring the potential for Small Craft Advisory conditions, which could persist into Friday. && .TIDES/COASTAL FLOODING... Astronomical influences (lunar perigee and full moon) along with periods of onshore winds could push tides to Coastal Flood Advisory levels near the times of the morning high tides along the South Carolina coast at least through the mid week. Right now, the best chance for minor coastal flooding looks to be Tuesday morning with the most pronounced northeast low level flow. However, given a front is expected to stall over the region through mid week, it will be difficult to predict the probability for any coastal flooding, since the wind direction will directly impact whether it will occur or not. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...BSH SHORT TERM...RFM LONG TERM...RJB AVIATION...BSH/RFM MARINE...BSH/ST/RFM TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service State College PA
1050 PM EST Sun Dec 11 2016 .SYNOPSIS... Low pressure will track north of Pennsylvania through the Great Lakes tonight. The trailing cold front will sweep through Monday, followed a period of more tranquil weather that will last through mid week. A true arctic air airmass and frigid temperatures will push southeast Into the area Thursday and Friday, accompanied by frequent snow showers and squalls. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 03Z radar loop showing precip redeveloping across Central Pa as low level jet and associated WAA overspreads the region from the west. At 0330Z, a wintry mix was falling over the Laurel Highlands with snow falling across the NW Mtns. KCCX CC returns also suggest mixed precip has spread into much of Cambria/Somerset/Bedford counties as of 0330Z, with snow further north. Radar trends and HRRR suggest precip will spread into the Susq Valley between 04Z-06Z. Model soundings support a ptype of snow to rain across the northern half of the state late tonight, while a freezing rain/rain mix turns to all rain in the south. Worst conditions in terms of travel should be late tonight, with improving conditions by the AM commute, as temps rise above the freezing mark over nearly the entire area by dawn. Additional snowfall based on latest model QPF and earlier superblend, is likely to range from 2-4 inches across the NW Mtns, to 1-2 along the I-80 corridor and nothing over roughly the southern third of the state. High pressure east of Pa, rather than over Northern New Eng, is in a less than ideal location to hold in the cold low level air, so expect only a brief period of freezing rain during the ptype transition late tonight. Stuck close to WPC ice accums of less than 0.1 inch across the Central Mtns, with perhaps a bit more on the ridgetops and less in the valleys. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... The low level jet and bulk of WAA will be shifting east of Pa by 12Z, so expect little additional precip during the daylight hours of Monday. Will maintain the chance for a bit of light rain during the AM hours associated with passage of trailing cold front. Lack of deep moisture in model soundings suggest any precip Monday morning will more likely fall as areas of drizzle, especially over the Alleghenies, where orographic forcing will play a role. As colder air flows over the lakes, a bit of lake effect snow is likely during the afternoon across the NW Mtns, where a fresh dusting appears possible by Mon evening. Elsewhere, expect patchy drizzle to last into the afternoon across the high ground of the Alleghenies, while downsloping flow yields brightening skies late in the day across the Susq Valley. Partial sunshine and later arrival of cold front should result in max temps Monday of close to 50F across the Lower Susq Valley, while cloud cover hold temps to the 30s across the Alleghenies. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... Cold front will bring a shot of greatly modified polar air into the region Mon night. High pressure slides through on Tue as flow aloft turns westerly. Digging trough dropping into NC U.S. and across Great Lakes midweek will be preceeded by a weak cold front and poss for light snow showers on Wed. Arctic front arrives Wed night, bringing the coldest airmass of this young winter into the region for Thursday and Friday. Temps Thursday could conceivably stay in the single digits across the higher terrain of the NW mtns and Laurel Highlands. The GEFS shows a large area of -2 to -3 sigma temps at 850 mb with min values around -20 F. Gusty West-Northwest wind accompanying the cold air will create below zero wind chills for much of the region Thu morning and only in the single digits during the daylight hours. Skies will become mainly clear with the wind dying off Thursday night as a 1025 mb sfc high build east from the nation`s heartland. Min temps early Friday could dip to zero to 5 below across the fresh snow covered ground of the Laurel Highlands and NW mtns, and will be in the single digits to teens across the Central and SE zones. Fair and dry (but very cold) weather is expected to persist Friday and Friday night. However, a moisture-laden storm will likely impact a large chunk of the region (beginning Friday night or Saturday) with snow changing to mixed precip or rain from the SW as a strong and rapidly warming southerly jet overruns the colder surface air (850mb temps may rise as much as 20-25C over a 36hr period from 12z Fri through 00z Sun). Although it`s still too early to give specifics on that storm w/resp to snowfall, both the EC and GEFS do show the parent storm heading NE from the mid Mississippi to the Upper Great Lakes. Since this storm track is so far to the NW, the deep valleys in Central PA could easily trap the cold, sub- freezing air into Saturday afternoon, bringing a slower or only partial changeover further north and east. As trough on back side of this system lifts across the Great Lakes, could see a period of light snow Sat night before high pressure builds in again on Sunday. && .AVIATION /04Z MONDAY THROUGH FRIDAY/... 21Z TAFS sent. Not a lot of change for the 00Z TAF package. Details below. Where it is snowing, it is IFR. Where it is not it is generally VFR. A general area of steady light snow is falling along and north of a line from about JST-UNV-SEG and will continue into the evening. Expect visibilities in the 1-3 mile range with ceilings generally under 3000` right through Monday morning. South of that line conditions will remain mainly VFR into early evening when a larger area of precipitation will overspread from the SW bringing widespread IFR/MVFR. South of I-80 a mix of freezing rain/snow and sleet will develop and continue overnight with the precipitation tapering off the mainly rain showers Monday morning. North of I-80 it will remain mainly snow with some sleet or freezing rain mixing in later tonight. Precipitation will taper off to scattered showers Monday with slowly improving conditions into Monday afternoon. Central and eastern terminals will likely improve to VFR by mid to late afternoon, while the higher elevation airports of the west and north will remain sub VFR probably into Tuesday. Outlook... Tue-Wed...MVFR/IFR snow showers NW. VFR elsewhere. Thu...MVFR/IFR snow showers NW. Windy. Snow Squalls possible with arctic fropa. Fri...No sig wx. && .CTP WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 10 AM EST Monday for PAZ004>006- 010>012-017>019-024>028-033>037-041-042-045-046-049>053- 056>059-063. Winter Weather Advisory until 4 AM EST Monday for PAZ064>066. && $$ SYNOPSIS...Fitzgerald/La Corte NEAR TERM...Fitzgerald SHORT TERM...Fitzgerald/La Corte LONG TERM...Lambert/RXR AVIATION...La Corte/Martin
Area Forecast Discussion
National Weather Service Duluth MN
918 PM CST Sun Dec 11 2016 .UPDATE... Issued at 918 PM CST Sun Dec 11 2016 The upper level shortwave was moving over far western Lake Superior as of 03Z per latest radar/satellite/model data. This wave will continue east clearing northwest Wisconsin and the Arrowhead after 06Z. The wave was enhancing the lake effect snow over western Lake Superior and causing light snow inland. KDLH low level velocity data supports the model low level wind forecast which showed the low level flow backing through the evening. As this has occurred, the snow showers have diminished along the North Shore into Duluth. As the wind continues to back, we expect lake effect snow to move through northern Douglas and Bayfield counties and possibly into portions of Ashland and Iron overnight. We do think as the wave departs, the lake snow showers will not be as intense as they are now. A shorter fetch will also keep the snow showers intensity lower than what has been occurring. We will likely be able to cancel the advisories and warnings for the Arrowhead to Duluth over the next hour but will keep them going for Douglas and Bayfield counties. UPDATE Issued at 746 PM CST Sun Dec 11 2016 Moderate to heavy Lake effect snow continued along portions of the North Shore into the Twin Ports area with light snow occurring further inland. Most of the snow has ended over western areas and clouds have diminished. The surface wind continued to back this evening and KDLH has gone north. It will take longer for the 925/850mb flow to back, but it will as the evening progresses. Lake effect snow will impact northern portions of Douglas and Bayfield counties through the evening but should diminish after midnight. We added those two counties to an advisory through midnight. An upper level shortwave was enhancing the lake effect snow and that is expected to move through the Northland late this evening or shortly after midnight. We left the snowbelt region of Ashland and Iron counties out of the advisory for now as confidence is not as high lake effect snow will impact those areas. The RAP sounding near Hurley shows a low level inversion present as winds veer then it lifts late tonight before winds go westerly. There may be a window of heavier lake effect that impacts those areas, but it should be brief. && .SHORT TERM...(This evening through Monday) Issued at 404 PM CST Sun Dec 11 2016 Snow continued across much of the Northland as of 330 PM. The heaviest snow stretched from the Duluth area, northeastward along the North Shore of Lake Superior. Snowfall amounts have been quite varied in this corridor, and the heaviest amounts correlated well with the location of the snow bands on Duluth radar this afternoon. The bands have been fairly stationary at times. The big focus will remain the snow accumulation tonight. The upper level vort max in association with the upper level wave will continue to bring waves of snow across the area this evening. High resolution models continue to indicate high QPF across the North Shore late this afternoon, shifting to the south shore of Lake Superior overnight. Decided to upgrade the advisory that was in effect for the coastal lake zones of the North Shore to a Winter Storm Warning. The interior portion of the Arrowhead will remain in an advisory, and the Duluth area has been added to the advisory as well. The focus for snow will shift to the South Shore of Lake Superior tonight, as winds become northeast, and eventually more north. This setup typically causes a band of locally heavy snow to develop in northern Douglas and Bayfield counties of northwest Wisconsin, and some of the high resolution models have hinted at that feature developing and then eventually breaking up later in the night as winds shift more to the west. Could see some decent accumulation along the south shore overnight, before winds switch to the west. The big focus for Monday will be the powerful cold front that is expected to push southeastward across the region. Much colder Arctic air will push in behind the cold front, and a band of persistent snow is expected to move through in association with the front during the day. This front will usher in some of the coldest air of the season thus far. .LONG TERM...(Monday night through Sunday) Issued at 502 PM CST Sun Dec 11 2016 Main concerns for the long term period involve much colder temperatures and the potential for accumulating snow later this week into the first half of the weekend. Strong cold air advection will continue Monday night behind the Arctic front expected to arrive during the afternoon. Northwest winds should remain somewhat strong Monday night, between 5 and 15 mph. Low temperatures will drop into the low single digits to teens below zero. The combination of winds and much colder temperatures will result in wind chills between 25 and 30 below zero by Tuesday morning. Wind speeds will increase to 15 to 25 knots over western Lake Superior behind the front Monday night. Gusts to 30 knots are likely. Occasional gale force gusts to 35 knots are possible over portions of the nearshore waters by Tuesday morning. Another Arctic cold front will advance southeastward through the Northland by Tuesday afternoon and evening. Winds will be strong once again during the overnight period with cold wind chills of 25 to 35 below zero expected. Winds will increase as the pressure gradient between strengthening surface high pressure over the Northern Plains and low pressure over northwest Ontario. Frequent gale-force gusts to 40 knots are possible over portions of the nearshore waters Tuesday through Thursday. Temperatures will fight to reach zero Fahrenheit with cold air advection continuing and partly to mainly cloudy skies expected. Wind chill values may remain in the 20s below zero through the day Wednesday before plummeting again Wednesday night. Low pressure over Ontario will eventually drift eastward toward New England Thursday night and Friday as ridging builds into the western Great Lakes. Winds will diminish and back southwesterly by Thursday. Temperatures may moderate slightly while remaining below normal for mid-December. Attention then shifts to another potential winter storm moving through the region during the Thursday night through Sunday morning timeframe. I won`t spend much time on details with this update. Suffice to say deterministic and ensemble guidance continues to feature a strong cyclone moving through the region, which could bring widespread accumulating snow to the Northland. Focusing on amounts at this time would toe the line of hubris. However, anyone with travel plans late this week into the weekend are encouraged to keep up with the forecast through the remainder of the week. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 546 PM CST Sun Dec 11 2016 The Northland continued to be impacted by a shortwave and surface low pressure system as well as lake processes. These features were combining to produce light snow over much of the Northland with moderate to heavy snow in spots around Lake Superior, mainly from the North Shore down into the Twin Ports. Surface winds were backing and KDLH has gone to north-northeast and KTWM/KBFW have also had backing winds. As this continues and the 925mb/850mb flow backs later this evening, the heavier lake effect snow will diminish and shift to the South Shore. The visibility has been as been as low as a half mile but most areas were 1 to 4 miles. The visibility will continue to increase for most areas but remain lower longer around Lake Superior. Ceilings will be a mix of MVFR and VFR and some clearing will impact at least the western half of Minnesota and possibly spots further east. Another quick moving shortwave will bring a chance for more snow on Monday and conditions will drop to MVFR/IFR. && .PRELIMINARY POINT TEMPS/POPS... DLH 7 12 -8 4 / 100 70 10 10 INL -9 6 -12 1 / 60 60 20 20 BRD -2 10 -9 5 / 20 60 10 10 HYR 10 16 -7 5 / 100 30 40 10 ASX 14 18 -1 8 / 100 30 30 20 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...Winter Weather Advisory until midnight CST tonight for WIZ001- 002. MN...Winter Weather Advisory until midnight CST tonight for MNZ012- 037. Winter Storm Warning until midnight CST tonight for MNZ020-021. LS...Small Craft Advisory until 4 AM CST Monday for LSZ121-140>148. && $$ UPDATE...Melde SHORT TERM...DAP LONG TERM...Huyck AVIATION...Melde
Area Forecast Discussion
National Weather Service Peachtree City GA
751 PM EST Sun Dec 11 2016 ...updated for 00z aviation discussion... .AVIATION... 00Z Update... expect cigs to begin/continue to lower toward IFR throughout the evening as warm air advection continues ahead of an approaching front. Not much change from the previous thinking of a chance of LIFR cigs just before or after sunrise ahead of the rain showers that will be moving into the TAF sites by late morning. cigs are not expected to improve much during the day with the rain and should remain around 1kft. biggest challenges are in the 10z to 14z timeframe and when cigs may drop to around 003 and winds shift to the SSW. expect shra most of the day and tapering off near sunset with continued low cigs behind the rain. winds will be tricky as ssw direction is expected in the early AM and a gradual westerly direction takes hold the remainder of the day. A shift to the north is expected late in the taf period. //ATL Confidence...00Z Update... Med confidence all elements. low confidence on timing of low cigs and wind shift in the AM. 30 && .PREV DISCUSSION... /Issued 245 PM EST Sun Dec 11 2016/ SHORT TERM /Tonight through Monday Night/... Tricky forecast on tap for overnight and Monday...and most of it revolves around the clouds. Persistent NE flow has kept much of northeast GA in the clouds this afternoon...while erosion of the deck has occurred on the south and west sides. Do expect most areas to fill back in after dark...but as the winds shift to the SW overnight ahead of a frontal boundary...the clouds should begin to erode again on the south and west sides. None of the models have a great handle on the winds overnight. The RAP at least keeps winds out of the east a bit longer across the NE and have chosen to populate the wind grids with the latest version. However, the models...even the hi-res ones...don`t handle these types of situations very well. So, low to med confidence in the cloud forecast overnight. Pops will increase from the NW late tonight as a cold front nears the CWFA. The best chances for measurable rainfall will be in the NW overnight. Areas that get socked in with low clouds could have patchy drizzle/sprinkles overnight. There is also some question on exactly how far south the frontal boundary will make it on Monday. With the 500mb flow begin zonal, the front may end up stalling a little further north than the models are currently progging. So, have lingered the highest pops in the vicinity of the I-20 corridor through Monday afternoon. NListemaa LONG TERM /Tuesday through Sunday/... Overall forecast looks to be on track through the extended period. Have mainly made adjustments to Day 7 temperatures and pops to better align with the (little) model consensus. Have also made some slight adjustments to dew points on Friday, which seemed a tad warm given the latest solutions. Otherwise, previous discussion still seems appropriate, and is included below. 31 && .PRELIMINARY POINT TEMPS/POPS... Athens 38 61 45 58 / 30 60 60 60 Atlanta 41 61 49 61 / 40 60 60 60 Blairsville 37 55 38 55 / 70 80 40 40 Cartersville 40 59 45 58 / 60 70 50 30 Columbus 47 69 56 67 / 30 50 60 60 Gainesville 38 57 44 55 / 50 60 60 50 Macon 44 70 55 66 / 20 40 50 60 Rome 41 60 44 58 / 70 80 40 30 Peachtree City 41 63 49 62 / 30 60 60 70 Vidalia 50 73 59 70 / 20 30 40 40 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...30 LONG TERM....17 AVIATION...30
Area Forecast Discussion
National Weather Service Wilmington NC
930 PM EST Sun Dec 11 2016 .SYNOPSIS... A coastal trough will push inland tonight. A cold front will drop into the area Monday night and possibly stall in the vicinity through Tuesday, before a stronger cold front moves through Wednesday night. As a result, a chance of rain can be expected through Wednesday with colder temperatures returning Thursday and Friday. Another coastal front and cold front may possibly affect the area next weekend. && .NEAR TERM /THROUGH MONDAY/... As of 930 PM Sunday...The coastal trough is at least 12 or 15 miles inland in Southeastern North Carolina. Between 8 and 9 PM the air temperature at the ILM airport rose from 49 to 59 degrees along with an increase in wind speed from calm to about 8 mph from the SE. The Sunset Beach nearshore buoy has just recently gone to a southeast wind and 61 degree air temp, so Myrtle Beach and the remainder of the Brunswick and Horry County coastline should see the trough push onshore very shortly. This forecast update makes tweaks to tighten the temperature gradient in the vicinity of this coastal trough over the next several hours as it begins to move inland from the coast. The other concern is the current anemic coverage of rain on the radar. PoPs have again been delayed, with hopes riding on an expansion in the intensity of isentropic lift along the 295K surface after midnight. The latest HRRR model not enthused about precip chances overnight, but if it`s going to happen it will be within this ribbon of relatively stronger lift expected to develop along the coast between 1-4 AM. Discussion from 630 PM follows... A touchy/tricky temperature forecast as moderate warm advection develops tonight and erodes away the increasingly shallow residual arctic air from the past couple of days. The coastal trough just offshore is moving westward and should bring rising temperatures overnight. The key question is do temperatures fall any over the next 2-3 hours due to modest radiational cooling through breaks in the clouds before warmer gulf stream air overspreads the area? The answer is probably a weak `yes` near the coast, but `no` inland where a more solid overcast appears to be settling in. I`ve put my best shot at it in this latest forecast update... lowering forecast lows by about 6 degrees at ILM, 2 degrees at LBT, but raising lows by 1 degree at FLO and 3 degrees at CRE. This gives low temperatures in the low to mid 40s inland with a narrow strip of upper 40s to lower 50s along the NC coast, and lower to mid 50s along the immediate SC coast. Rain chances probably won`t become significant until better isentropic lift develops after midnight, so I`ve trimmed back PoPs through the evening hours to slight chance across the SC Pee Dee region and dry elsewhere. In terms of the current position of the coastal trough it appears the 18z NAM and 12z WRF-ARW have the best handle on this, and both models support that idea for precipitation timing overnight. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... As of 300 PM Sunday...Fast but broad cyclonic flow in the mid- levels will allow features to move quickly this period, but maintain unsettled weather into mid-week. A coastal trough/warm front will be north of the area Monday morning, and Monday will feature temperatures well above normal. The MET/MAV numbers are in good agreement with highs around 70 at the coast, but only around 60 well inland. This is due to the current wedge, which will be difficult to break down despite the lifting front as mid-level thicknesses stay relatively constant. The guidance tends to break these wedges down too quickly, so will hedge towards the coolest guidance for Monday but note large bust potential if WAA does overcome more strongly. While much of Monday will likely be dry, continued isentropic lift as well as forced lift along the boundary will create light showers through late morning, focused primarily near the NC coastal counties. NAM is very aggressive with rainfall Monday, and is ruled out due to lack of forcing, and continued dry mid-level air. Showers will end by early aftn from SW to NE, before a cold front trailing from a New England low pressure moves into the Carolinas Monday night. Moisture return ahead of this feature is limited, but showers may redevelop Monday night ahead of the boundary. This front will stall either across, or just south, of the CWA on Tuesday, leading to cooler temperatures and continued cloudiness. Strengthening isentropic lift atop this front and the high pressure behind it will again lead to increasing rain chances, and forecast profiles suggest the deepest saturation of the short term will be late Tuesday. Once again, do not expect a high QPF event, but many places will receive a second round of light rain late on Tuesday, but temps will remain above seasonable levels. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 PM Sunday...1200 UTC GFS and 0000 UTC ECMWF are generally similar in the extended pattern. Low pressure is expected to be located off the NC coast Wednesday with a strong cold front approaching from the northwest. A better moisture profile is evident during Wednesday into Thursday evening before significant drying and subsidence occurs with the passage of the aforementioned front. Isentropic glide is mostly neutral by Wednesday morning and low- level theta-e advection is nominal as well. However UVVs are present with support from strong H3 jet north of the region and the low- level front lingering across the area. The resulting categorical GFS POPs may be overdone as a result, but in the end the chance of rain will persist until Wednesday night. Low-level wind fields increase Wednesday night and persist into Thursday. If the current scenario pans out then expect gusty northwest winds Thursday as mixing occurs. Gusty northerly winds would also be a good bet Friday morning given the strength of the wind field prior to weakening later in the day. The surface high will ridge into the area from the Midwest Thursday then translate to the Mid-Atlantic coast Friday evening and another spate of below normal temperatures will occur through at least Friday night. Trends this weekend are for another coastal trough to move inland with return flow developing ahead of another cold front very late in the period. Chance POPs will be needed by this weekend to account for the coastal trough and late in the weekend for the next cold front. At this time it appears that temperatures will warm in time before any precip arrives late Friday night into Saturday morning. However given the level of uncertainty this far out in time, a slight concern exists that the earlier arrival of precipitation Friday night would be more closely aligned with the colder temperatures and a very slight potential for P-type issues. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... As of 00Z...VFR conditions prevail at all terminals attm though MVFR conditions are expected to develop tonight. LIFR/IFR CIGS are also possible toward 12z along with potential for -DZ/-RA. A coastal trough has begun to push inland allowing the winds to veer to an E direction at the coastal terminals. Additional veering of the winds is expected as this feature is drawn inland. Extended Outlook...CIGs improving Mon afternoon or evening. Periods of MVFR/-RA Mon night through Wednesday with IFR most likely during the morning hours. VFR Thursday in the wake of a cold front Wednesday night. && .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 930 PM Sunday...According to buoy and coastal weather observations, the coastal trough is now west of the coastal waters with south to southeast winds now increasing across the area. Air temperatures have risen into the lower to middle 60s, and could rise even further overnight near Cape Fear as southerly winds strengthen. Models still support minimal small craft advisory conditions developing near and north of Cape Fear after midnight with 20-25 kt winds and seas reaching 5-6 feet in open waters away from shore. Discussion from 630 PM follows... A coastal trough is located about 15-30 miles off the coast as indicated by latest observed wind directions showing east to northeast wind on the beaches but southeast winds out at the Frying Pan Shoals buoy. This trough is best defined in the 18z NAM and 12z WRF-ARW models, and these have been used for this forecast update tonight. The main change in the forecast was to show a much more backed wind direction this evening before the coastal trough moves onshore and turns winds solidly southerly. No changes have been made to the Small Craft Advisory as increasing southerly winds overnight should make conditions more hazardous late, especially across the North Carolina waters. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... As of 300 PM Sunday...The period begins with an SCA in place across the NC zones due to gusty southerly winds of 15-25 kts and 4-6 ft seas. Across SC waters, morning conditions will be slightly better, with 10-20 kts and 3-4 ft seas. As the coastal trough currently across the waters lifts north on Monday, wind speeds will ease to 10- 15 kts, and then shift abruptly to the NW Monday night behind a cold front. This front will then waver across the waters much of Tuesday creating highly variable winds around 10 kts, becoming north late. After the initial SCA threshold seas, wave heights will fall to 3-4 ft by Monday night, and then remain at these amplitudes through the end of the period. LONG TERM /WEDNESDAY THROUGH FRIDAY/... As of 300 PM Sunday...Low pressure off the NC coast Wednesday with a cold front south of the waters will maintain light N-NE flow which is expected to become variable later in the day and evening. Offshore flow will quickly ramp-up Wednesday night as low pressure exits and a stronger cold front sweeps across the waters. Small Craft Advisory conditions will likely concern as the NWly winds peak Thursday. High pressure originally northwest of the waters during Thursday will build eastward toward the Mid-Atlantic region allowing the winds to gradually subside and veer to a NEly direction Friday. Seas around 3 ft will build to Small Craft thresholds Thursday morning with 6-7 footers possible off Cape Fear. Seas will only slowly improve through Friday as the Nly fetch becomes NE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...Small Craft Advisory until 10 AM EST Monday for AMZ250-252. && $$ SYNOPSIS...SRP NEAR TERM...TRA SHORT TERM...SRP LONG TERM...SRP AVIATION...RAN
Area Forecast Discussion
National Weather Service Indianapolis IN
958 PM EST Sun Dec 11 2016 .UPDATE... The NEAR TERM Section has been updated below. && .SYNOPSIS... Issued at 246 PM EST Sun Dec 11 2016 The winter storm system currently moving through the Midwest will keep chances for rain south and a wintry mix north going until late tonight. After that high pressure builds in to dry things out across the area through the week. Temperatures will drop off starting Tuesday night and drop sharply for Wednesday night and Thursday, with wind chills possibly getting well below zero early Thursday morning. The next storm system to impact the area will arrive Friday to bring in precip chances for next weekend. && .NEAR TERM /Overnight/... Issued at 959 PM EST Sun Dec 11 2016 More widespread precipitation spreading back into the northwestern half of the forecast area ahead of the cold front currently tracking across Illinois. With southwest flow now across the area...the low levels continue to warm with 02Z temps ranging from just above the freezing mark over far northern counties to near 40 degrees in the far south. Primary focus is on precipitation for the next 6 hours or so as this band of light precipitation slowly rotates east through the forecast area. Low level thermal profiles remain suggestive that snow is mixing in with the rain over far northern portions of the forecast area. HRRR analysis over the next several hours keeps the potential for snow and/or sleet to briefly mix in with the rain generally north of a Crawfordsville to Anderson to Muncie line with rain over the rest of the area. May see an additional light snow accum less than an inch within the advisory area over the next few hours and will miaintain headlines as is. Steady precip should be east of the forecast area by 08-09Z with low clouds lingering. Will need to monitor potential for some pockets of drizzle surface temps fall once the front passes...freezing drizzle towards daybreak as model soundings favoring development of a sharp inversion around 2-2.5kft as drier air aloft advects into the region. This will also serve to keep a thick low stratus in place through daybreak as well. Temps will rise a few more degrees ahead of the cold front...then expect temps to fall predawn with much of the forecast area north of I-70 below freezing by daybreak. Zone and grid updates out. && .SHORT TERM /Monday through Wednesday/... Issued at 246 PM EST Sun Dec 11 2016 The short term will be relatively quiet weather-wise as high pressure builds over the area from the northern plains. Weak cold advection will be in place Monday through Tuesday but may also see the sun in places to offset that, so looking for highs in the 30s both days. By Tuesday night though the cold advection gets a little stronger and should see colder air moving in, with low temperatures dropping into the single digits in the north Tuesday night. Wind chills Tuesday night into Wednesday morning could drop below zero in the northern counties as a result. && .LONG TERM (Wednesday night through Sunday)... Issued at 211 PM EST Sun Dec 11 2016 Although the deterministic models have differences, they lend good confidence in an arctic airmass overspreading the area at the beginning of the short term and a strong weekend weather maker. Wednesday night looks to be the coldest night in 11 months and possibly or more as arctic high pressure builds in from the Missouri Valley and results in mostly clear skies. With strong potential for strong radiational cooling, went along with adjacent offices on lowering overnight lows a couple degrees to 0 degrees or slightly lower for our northern boundary and near 10 degrees across our southern boundary. Highs Thursday should only reach the upper single digits northern sections. After that, the high will shift to Appalachia on Friday. Return flow around the high and ahead of a deepening Rockies system will allow for a nice warm up with highs back up in the 20s and lower 30s on Friday per the blend. It will also result in overrunning accumulating snow that will continue through at least Friday night. Model soundings, critical thicknesses and blend temperatures suggest the snow could mix with or change to freezing rain Friday night or Saturday and rain later in the day on Saturday. The 00z ECWMF was slightly quicker and stronger with the system, moving the associated cold front through the state by 18z Saturday. The GFS continued showing QPF through Sunday associated with fast moving upper impulses, while the ECMWF was dry. Small regional blend pops into Saturday night and dry Sunday look like a reasonable blend. && .AVIATION /Discussion for 120300Z TAF Update/... Issued at 959 PM EST Sun Dec 11 2016 Ceilings continue to tumble as more widespread precipitation spreads back into central Indiana. Made some minor tweaks based on current obs...otherwise no changes needed. 00Z discussion follows. Poor flying conditions will continue through tonight with only gradual improvements in low ceilings on Monday. A combination of reports received...LAPS sounding analysis and hydrometeor classification via the 88D all suggesting that the only terminal still experiencing mixed precip is at KLAF. The other three sites are warm enough for a cold rain. The near surface layer will continue to warm over the next several hours as low level flow veers to the southwest as low pressure tracks into the western Great Lakes. Will continue with a ra/sn mix at KLAF into the evening. Deeper moisture will depart after 06Z with the cold front following shortly thereafter during the predawn hours. This will effectively shut off the precipitation with the possible exception of DZ or perhaps FZDZ as surface temps slip back below freezing prior to daybreak Monday. The primary issue for aviators going forward into Monday will be if and how quickly the stratus deck and lift and scatter as model soundings show a sharp inversion developing at 2-2.5kft and holding for the better part of the day. With much drier air aloft building into the region along with high pressure...can certainly see a scenario play out where the moisture remains deep enough trapped beneath the inversion to keep the cloud deck in place most of if not the entire day. The strength of the inversion also opens the possibility for a continuation of pockets of DZ/FZDZ or even a few flurries. Will try to be somewhat optimistic and allow for scattering of the deck at both KBMG and KHUF where the inversion is likely to be weaker. Have held onto the stratus at both KIND and KLAF for most of the day. Will hold off on any mention of DZ/FZDZ/Flurries...but will monitor closely into the overnight. Winds will shift to W/NW behind the front Monday at 10-15kts. && .IND WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 1 AM EST Monday for INZ021-031. && $$ SYNOPSIS...CP NEAR TERM...RYAN SHORT TERM...CP LONG TERM....MK AVIATION...RYAN
Area Forecast Discussion
National Weather Service Northern Indiana
633 PM EST Sun Dec 11 2016 .SYNOPSIS... Issued at 628 PM EST Sun Dec 11 2016 Periods of snow will continue through the evening and may mix with drizzle or freezing drizzle at times. This will keep roads slippery and hazardous overnight. The snow will gradually end overnight. Dry weather is expected on Monday and Tuesday with much colder temperatures arriving for Wednesday through Friday. Highs on Thursday may only be in the single digits with lows below zero. There could also be some light lake effect snow when the colder air arrives. && .SHORT TERM...(This Evening through Monday) Issued at 332 PM EST Sun Dec 11 2016 Strong LLJ ahead of approaching wave and in right rear quadrant of intensifying 300mb jet continuing to support broad swath of 290K isentropic ascent and mod snow. This activity will continue across our north through the early evening with a brief lull in our southern counties before main convergent boundary swings through the area 00-06Z. Loss of midlevel moisture/ice nucleation currently generating light freezing drizzle in our southern counties but RAP and HRRR suggest deeper moisture will return around 00Z. As previously mentioned, earlier snowfall associated with strong isentropic ascent and slightly colder profiles seen in 12Z guidance prompted an increase in snow forecast and expansion of headlines along the US-24 corridor. However, no other expansion is planned given latest reports in northern tier of advisory only 5-6 inches with freezing drizzle/compaction and only another inch or two this evening. Still expect a brief mix of just rain/drizzle in our far SE counties and this will prevent much additional accumulation. Models indicate there will be a brief uptick in elevated fgen across our NW counties around 00-03Z this evening as main wave approaches. With some decent instability above 600mb, this could lead to some heavier bands developing. This would primarily be in our NW third...well NW of US-24. Inherited forecast reflects this reasonably well and only minor changes made for this package. End time of 06-09Z still appears in very good shape and no changes planned to end time of headlines. Slight concern for very brief freezing drizzle on backside of exiting front but abrupt/deep dry air advection and isentropic descent should be enough to cut off all precip by the time DGZ is unsaturated. Dry conditions expected during the day Monday with temps holding around 30F. && .LONG TERM...(Monday Night through Sunday) Issued at 332 PM EST Sun Dec 11 2016 Main story for the rest of the period is very cold temps. 850mb temps drop (in stairstep fashion) to near -25C by early Thursday with 925mb temps around -20C. This yields high temps in the single digits with lows below zero. Cut consensus blends which appear too heavily weighted toward climo and may need further cuts, especially to overnight lows Thursday night. Wind chill headlines may be necessary on Thursday with a modest gradient in place. A few periodic chances for lake effect snow in NW CWA, particularly on Thursday with coldest thermal profiles. Extreme dry air entrainment expected given arctic airmass with limited convective depths and instability despite high delta-T`s. This will limit snowfall amounts and only light accumulation expected. Attention then turns to next longwave trough slated to arrive late Friday into Saturday. GFS and ECMWF in reasonable agreement on the big picture but differ with regard to important details that will determine precip types and amounts. Mixed precip is certainly possible during this time but still much too early to discuss any specifics. Will leave precip type as just snow for now with plenty of time for adjustment. && .AVIATION...(For the 00Z TAFS through 00Z Monday Evening) Issued at 628 PM EST Sun Dec 11 2016 Loss of ice nucleation with mid level dry slot has led to drizzle and freezing drizzle. KSBN should see pcpn back to snow shortly as deeper moisture along frontal zone works back east. Period of moderate snow expected at KSBN as indicated by upstream observations and mid level forcing this evening. KFWA likely to see a few more hours of the DZ/FZDZ until deeper moisture arrives and light snow develops again. Expect all pcpn to diminish late tonight with a very small chance for another brief period of FZDZ as pcpn diminishes. Monday should be dry with improving conditions. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...Winter Weather Advisory until 4 AM EST Monday for INZ020-022>027- 032>034. Winter Storm Warning until 4 AM EST /3 AM CST/ Monday for INZ003>009-012>018. MI...Winter Storm Warning until 4 AM EST Monday for MIZ077>081. OH...Winter Weather Advisory until 4 AM EST Monday for OHZ016-024-025. Winter Storm Warning until 4 AM EST Monday for OHZ001-002-004- 005-015. LM...Small Craft Advisory until 4 PM EST Monday for LMZ043-046. && $$ SYNOPSIS...AGD SHORT TERM...AGD LONG TERM...AGD AVIATION...Lashley Visit us at Follow us on Facebook...Twitter...and YouTube at:
National Weather Service Jackson KY
1034 PM EST Sun Dec 11 2016 .UPDATE... Issued at 1034 PM EST SUN DEC 11 2016 Widespread rain is solidly in place near and north of the I-64 corridor. The rain will continue to spread across the rest of the area through the overnight hours. Forecast has this covered well. Temperatures have stayed quite a bit higher prior to the onset of rain, so have adjusted temperatures up prior to the rainfall overnight. In fact, many areas are still in the low 50s at this late hour. UPDATE Issued at 548 PM EST SUN DEC 11 2016 Updated to toss in some sprinkles through the early evening hours before we saturate enough to allow for better rainfall potential later this evening. Some light radar returns continue to work into the area. The heavier rainfall looks to hold off until late evening into the overnight hours. && .SHORT TERM...(This evening through Monday night) Issued at 355 PM EST SUN DEC 11 2016 20z sfc analysis shows a fairly deep area of low pressure moving into the mid Mississippi Valley and helping to tighten up the gradient in pressure through Kentucky thanks to a high off to the east. The winds picked up in conjunction with this so that they are gusting to the 20 to 25 mph range from the south to southwest for many sites in the higher terrain of the east and the more open locations to the west. Just thin and patchy high clouds in the east also helped to mix down higher winds from aloft and contribute to pleasant temperatures rising into the upper 40s to lower 50s for most locations. Dewpoints, meanwhile, remained in the lower 20s and upper teens yielding relative humidity levels down near 25 percent. The models are in good agreement aloft through the short term portion of the forecast. In fact, they are nearly identical with the way they handle the trough crossing north of the Great Lakes. South of this, energy will zip through the Ohio Valley in the fast flow - sweeping through tonight as the heights fall with the trough passing. However, the core of this rather low amplitude wave will stay well to the north of Kentucky. Heights will hold fairly steady into Tuesday morning as fast and mostly zonal flow continues through the area at mid levels. Given the agreement in the models have favored a general blend for the forecast with a lean toward the latest HRRR and NAM12 for specifics through tonight. Sensible weather will feature temperatures dropping off a few degrees for most places this evening before the thicker and lower clouds push in with an extended period of rain showers ahead of the front. Continued southwest flow will support temperatures holding fairly steady in the mid 40s most places overnight during the rain. The front passes through eastern Kentucky by mid morning Monday - drying out the CWA from northwest to southeast - with just some limited CAA on its heels. Do still expect a bump up in temperatures for an afternoon high on Monday. High pressure then moves quickly overhead by evening and ending the CAA before midnight along with only marginal radiation cooling anticipated that night due to lingering low clouds. The net result will be temperatures pretty much near normal for this time of year and only liquid pcpn seen for us from this system. Again started with the CONSShort and ShortBlend for the grids through the short term with only minor temperature adjustments tonight given the non-diurnal curve anticipated. Did also adjust the PoPs to better define the fropa tonight into midday Monday. .LONG TERM...(Tuesday through Sunday) Issued at 355 PM EST SUN DEC 11 2016 The period begins with surface high pressure attempting to build south as it cruises across the Ohio Valley. Meanwhile a surface low develops across portions of MS and AL and will remain south of eastern KY. Therefore not buying into the ECMWF bringing precip this far north Tue and in Tue evening and therefore backed off the superblend for that period. The weather remains quiet after this as the clipper system seen in previous model iterations has shifted north across the northern Ohio Valley region. However, the NW flow pattern could lead to some upslope flurries Thursday morning with soundings suggesting just enough moisture residing in the dendritic growth zone. Otherwise cold air mass and high pressure will build across the region. Thursday night will be the colder night with temperatures dropping into the teens area wide and even a few single digits possible in the eastern valley sites. Opted not to go too crazy given the crest of the surface high remains in question, but certainly could see this trending colder. The forecast becomes convoluted moving into the late week time frame as models struggle to become consistent. The onset of the next system could be some kind of wintery precip, however what kind of ptype remains the question. Given we are talking day 6 and the inconsistency opted to keep this simple mix/snow/rain type setup. That said, the concern right now is the onset Saturday morning, with model soundings and ascendant conditions suggesting a short window of freezing rain potential before WAA takes over. The precip will then switch to and remain rain through much of the day on Saturday into Saturday evening. Finally we will see another switch from rain, mix to snow by Saturday night into Sunday morning. Given the overall timing issues will continue to lean heavily toward the superblend for the overall forecast evolution. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) ISSUED AT 800 PM EST SUN DEC 11 2016 A cold front advancing across eastern Kentucky tonight into Monday will bring lowering ceilings through tonight, eventually getting into the IFR range late. Widespread rain will also spread across the area overnight and lead to some patchy fog at times. All the rain should depart early Monday, but IFR clouds will be slow to lift to MVFR on Monday and we may not get out of MVFR skies on Monday. Gusty south winds will be seen ahead of the front this evening before we see them transition to southwest and turn lighter. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KAS SHORT TERM...GREIF LONG TERM...DJ AVIATION...KAS
Area Forecast Discussion
National Weather Service Melbourne FL
922 PM EST Sun Dec 11 2016 .UPDATE... ...Fog/Low Stratus Expected Early Mon Morning... Tonight...The center of a large high pressure area will move steadily away from the mid Atlantic coast. This will cause low level winds to veer to a southerly direction late while weakening. Canaveral profilers still show east/southeast winds around 20 knots in the low levels, and this was generating scattered showers over the Atlantic, with a few bands moving into the coast. The steady veering of low/mid level winds will keep most of this shower activity over the Atlantic by late tonight. There is going to be considerable low/mid level cloudiness lingering most of the night, but as low level winds diminish in saturated environment, expect low stratus and areas of fog to develop late. The GFS MOS has been consistent in the past 24 hours showing this. Not sure with the boundary layer flow staying near 10 knots how low surface visibilities will go, but these "sloppy" warm front type situations can often produce dense fog. The HRRR and local WRF have been showing low visibilities primarily inland and near the north coast. Have broadened mention of areas of fog to include much of the area and would expect some patches of dense fog towards sunrise. && .AVIATION...Isolated to scattered showers were moving northwest over the Atlantic and along portions of the coast. This has been producing mainly MVFR conditions. After midnight, most of this activity will stay over the Atlantic as low-mid level winds veer to southerly and gradually diminish. Then, the very moist low levels will promote low stratus and fog. MOS guidance has been hitting areas along and west of the I-4 corridor hard with LIFR conditions. Trended the ceilings/visibilities down considerably from the previous forecast. With the widespread low cloudiness it should take until at least 15z to get back to MVFR-VFR conditions. && .MARINE... Tonight-Mon...The latest surface analysis shows the pressure gradient starting to slacken, even though the GFS has a solid 20 knot east/southeast flow in the low levels. The models have been showing a decrease in the gradient as winds veer around to the south. Gusty conditions will likely continue overnight, especially in the Gulf Stream, so won`t change small craft advisory that is in place until 4 am. Exercise caution conditions will likely continue Mon morning, especially offshore, then by afternoon southwest winds will diminish to 10 knots or less. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...Small Craft Advisory until 4 AM EST Monday for Sebastian Inlet to Jupiter Inlet 0-20 nm-Sebastian Inlet to Jupiter Inlet 20-60 nm-Volusia-Brevard County Line to Sebastian Inlet 0- 20 nm-Volusia-Brevard County Line to Sebastian Inlet 20-60 nm. && $$ Lascody/Blottman
Area Forecast Discussion
National Weather Service Omaha/Valley NE
941 PM CST Sun Dec 11 2016 .UPDATE... Issued at 920 PM CST Sun Dec 11 2016 The main changes for the evening updates were to exit some flurries/clouds out of the area and significantly lower low temperatures. By 03z...temperatures already close to zero near the SD border and approaching with around 10 deg. at FET. Still 1 to 3 inches of snowcover in northeast Nebraska, so conditions favorable to bottom out. The RAP seemed to have the best trend for temps as the other models were too warm. Surface winds will continue to diminshing with mostly clear skies and cold high pressure over the area. Low level winds do come around to the southwest and increase to 30kts by 12Z and in turn could result in some increasing clouds and possibly flurries later in the am. The saturated layer is only 40mb thick with a lot of dry air something to pass on to the next shift. && .SHORT TERM...(tonight through Wednesday night) Issued at 257 PM CST Sun Dec 11 2016 Flurries/snow pellets are on their way out, with quieter weather to follow for the next few days. Subjective 12Z upper-air analysis indicates fast and mainly zonal flow, with a few shortwave troughs rippling through the flow. Also zonal upper-level jet extended from OR/northern CA through WY-CO/SD-NE toward the Great Lakes and southern New England. An 850mb low was centered in ND, with a fairly tight temperature gradient/baroclinic zone from BC through MT/SD before loosening over the upper MS River valley/western Great Lakes. Surface trough at 20Z extended from southern WI through eastern IA to an elongated low from northeast MO to northeast OK. Surface high was noted across the Dakotas into western NE. Main forecast concern in the short term is potential for on and off flurries, along with a few temperature swings. As long as fast zonal flow with weak ripples and some mid=level moisture all continue across the central US, some flurries could occur as any wave passes. Tonight into Monday looks safe as surface to mid-level ridging passes through. Mins tonight should reach early lows in the western CWA before return flow allows some improvement behind the surface ridge. Despite cold lows tonight, warm air advection and mainly partly cloudy skies on Monday should allow temperatures to recover into the 30s and 40s across the area. Plunging cold front on Monday evening should bring much colder readings on Monday night and Tuesday. Maybe the front brings a flurry or two, but do not currently have a mention in the forecast given the low confidence. Otherwise, lows in the single digits to teens and highs in the upper teens to 20s are expected. Another one of those upper-level shortwave ripples may slide through around Tuesday night, but with little moisture, again think that the best it might muster are flurries, which again are not mentioned given low confidence. Temperatures remain generally neutral through Wednesday night, with lows in the upper single digits to lower teens and highs in the upper teens to mid-20s. .LONG TERM...(Thursday through Sunday) Issued at 257 PM CST Sun Dec 11 2016 Upper-level trough is progged to dig into the western US from Thursday into the early weekend before ejecting across the central US through the weekend. GFS/ECMWF solutions are actually in fairly good agreement on the feature, with some minor differences on timing. Ahead of the system, warm air advection on Thursday into Friday may boost temps particularly on Thursday night and Friday, when highs might reach back into the upper 20s to upper 30s, depending on solution. Do have a small area of light snow mentioned later Thursday, but confidence is rather low. Thursday night, a band of snow in the warm air advection seems likely across the Dakotas into MN/IA, which may just clip the northeasternmost CWA. Despite slight chance POPs on Friday morning, actually think most of Friday could be dry until front passes through later on Friday and into Saturday. Even then, dry slotting could keep part of the CWA dry or with lower chances of precipitation (especially the southern CWA), while confidence is higher in precipitation in the northern CWA. Current thermal profiles would suggest all-snow north, and perhaps a rain-snow mix on Friday afternoon in the southern CWA if it does in fact rain. That said, thermal profiles on the edge of freezing are tricky to forecast reliably at day 6, and mixed-phase precipitation in general is possible. Precipitation should end as snow as cold- air advection continues in earnest Friday evening through Saturday. Any lingering snow on Saturday will move eastward and out of the area, with cold air plunging into the central US. Coldest temps will be expected where any snowpack remains from the late week event. That said, with high pressure near on Saturday night, along with clearing skies behind the exiting system, imagine it will be a very cold night in some areas. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 520 PM CST Sun Dec 11 2016 Patchy MVFR conditions will end early this evening with decreasing clouds and VFR conditions overnight. Northwest winds will diminish and become southerly on Monday as high pressure builds through the region. The next cold front will push through the area Monday afternoon but did not include another group for that wind shift at this time. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ UPDATE...Zapotocny SHORT TERM...Mayes LONG TERM...Mayes AVIATION...Miller
Area Forecast Discussion
National Weather Service Norman OK
749 PM CST Sun Dec 11 2016 .UPDATE... Updated cloud cover and min temperatures. && .DISCUSSION... Cold air advection and diurnal cooling continue this evening and temperatures were already falling below current hourly grids. Although we will have some cirrus to contend with (and have updated sky grids to account for this cirrus), light winds and partly cloudy skies will still allow for some good radiational cooling as surface ridge moves into the northwest. The RAP and HRRR seemed to have a good handle on current temperature trends and both forecast cooler temperatures by sunrise in northern and western Oklahoma than were in the grids, so have lowered mins in the north and west closer to the mins forecast by the high- resolution models. && .PREV DISCUSSION... /issued 612 PM CST Sun Dec 11 2016/ DISCUSSION... AVIATION... MVFR ceilings will move southeast of central Oklahoma this evening in the wake of a weak cold front. Gusty north winds will subside by midnight. VFR conditions and light winds are expected until mid-day tomorrow when south winds will arrive to western Oklahoma. Speeds are expected under 12 kts generally. PREV DISCUSSION... /issued 302 PM CST Sun Dec 11 2016/ DISCUSSION... An active pattern is expected through this week with a series of cold fronts expected to pass by Oklahoma and north Texas. The first cold front is progressing southeastward today with temperatures falling into the 40Fs and gusty northerly winds behind the front. Ahead of the front, temperatures have warmed into the upper 60Fs and low 70Fs. Expect the passage of this front to result in high temperatures to be near average (low to mid 50Fs) for tomorrow afternoon. On Tuesday, the next cold front is expected to gradually pass by the area. Temperatures will only be slightly cooler behind this front. An even stronger, reinforcing push of cold air is expected on Wednesday. This will drop high temperatures 10-15F below average for Wednesday and Thursday. Significant warm air advection--aided by an intense 50-55 knot low-level jet--is expected to commence late Thursday into Friday. Rain and/or drizzle may develop due to isentropic ascent in response to the warm air advection. Currently, anticipate any areas of precipitation to be coincident with temperatures above freezing as temperatures will likely warm through the night. Therefore, expect any precipitation to stay liquid for now. Increased wind speeds on Friday beyond blended guidance based on 925-850 mb wind speeds and the tight surface pressure gradient. Also opted to raise temperatures above blended guidance for Friday afternoon as low-level thermal fields are progged to be quite warm (850 mb temps >=15C across the west) with west- southwest flow. Many locations may reach the 60Fs with some temperatures near 70F possible across western north Texas. Some remnant warm air advection rain/drizzle will be possible on Friday. On Saturday, another seasonably strong cold front is expected to pass by Oklahoma and north Texas. In the front`s wake, falling temperatures into the 30Fs and gusty northerly winds are expected. The 11/12Z GFS and ECMWF are in better agreement that precipitation chances look very low behind the cold front. Therefore, opted to keep post-frontal weather dry on Saturday for now. Seasonably cold temperatures are expected to persist into Sunday. Mahale && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 29 51 31 47 / 0 0 0 0 Hobart OK 29 49 32 47 / 0 0 0 0 Wichita Falls TX 28 53 36 54 / 0 0 0 0 Gage OK 23 50 24 43 / 0 0 0 0 Ponca City OK 24 48 25 41 / 0 0 0 0 Durant OK 36 55 42 55 / 10 0 0 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...None. TX...None. && $$