Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/14/17

Area Forecast Discussion
National Weather Service Columbia SC
1009 PM EST Fri Jan 13 2017 .SYNOPSIS... A backdoor front will move into the region tonight and Saturday and provide a slight chance of showers through early next week. A front will bring showers and possible thunderstorms late Wednesday and Thursday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Surface high pressure will continue to build into the Northeastern US overnight while a back door cold front drops south into the area. Convergence near the front along with weak isentropic lift over the boundary may produce light showers in the northern Midlands. However, the HRRR keeps most of the shower activity further north. Low stratus is expected to develop tonight through Saturday morning. With increased moisture along the frontal boundary and shallow, cool air pushing into the CSRA, areas of fog are also expected to develop tonight across the CSRA. Winds will be light. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... Front will continue to back door into our forecast area (FA) Saturday, bringing some cooler temps, mainly north and central FA, with slight chance showers mainly north and mainly early. Temperatures Saturday will range from the lower 50s near the NC/SC border to the upper 60s southern Midlands/CSRA. Weak low- level wedge appears could gradually erode Sunday as another boundary shifts SE and appears to back door either into our region or possibly remain just to our NE. The shower chance appears minimal with only weak isentropic lift and not much upper energy. Followed guidance blend on most elements. && .LONG TERM /MONDAY THROUGH FRIDAY/... High pressure surface and aloft appears to provide fair and warm conditions Monday and Tuesday. Latest GFS continues to indicate significant moisture late Wed night thru Fri, as a series of upper disturbances roll through. Will continue mention of slight chance thunder to accompany the shower chances with indications of considerable low level jet and sufficient instability. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... The backdoor front will push through the area late tonight and early Saturday. Nocturnal cooling and moisture convergence ahead of the front will help support stratus and fog late. Stratus and fog will likely persist behind the front during the rest of the TAF period. Leaned toward the GFS LAMP for the timing of developing MVFR and IFR conditions late tonight and early Saturday morning. Convergence along the front may also help support drizzle. There may be slight diurnal improvement late in the morning and early afternoon, but uncertainty is high because of model inconsistency. Followed the more optimistic NAM MOS because of h85 westerly flow and forecasted IFR conditions becoming low-end MVFR. Variable wind will become light northeast behind the front. EXTENDED AVIATION OUTLOOK...A stationary front near the area Sunday and Monday will likely become a warm front and lift north of the region Tuesday. A cold front is forecast to move into the area Wednesday. The pattern supports possible widespread stratus and fog especially during the early morning hours Sunday through Tuesday. Showers associated with the cold front may bring restrictions Wednesday. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
Area Forecast Discussion
National Weather Service Charleston SC
932 PM EST Fri Jan 13 2017 .SYNOPSIS... High pressure to the north will persist through the weekend before shifting offshore and lingering through late next week. A weak cold front could impact the area for the middle portion of the week. && .NEAR TERM /THROUGH SATURDAY/... As of 915 PM: Latest satellite and sfc observations indicate that the backdoor cold front was located near of the NC/SC state line. In fact, KLTX radar detected a fine line associated with the front, the boundary was sliding SW at 20 kts. Based on the observations, it appears that the front is outpacing the HRRR by nearly two hours. At the current pace, the front would reach Charleston and Berkeley Counties around 7Z. Recent guidance indicates that the front will begin to stall within the lower Savannah River Valley. I will update the forecast to adjust sky and winds to the latest frontal timing. As of 650 PM: Satellite and sfc observations indicated that a backdoor cold front will located west to east across Raleigh, NC. This front should drive southwest tonight, expected to reach Charleston and Berkeley Counties by 9z. Forecast soundings appears quite moist below 4 kft after the front. I will increase the sky cover and adjust timing of BKN sky. In addition, I will adjust the wind shift associated with the backdoor cold front to align with latest high resolution guidance. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... Confluence aloft will drive a back door type cold front across SC early Saturday, sinking south of Savannah, GA by late morning. Although cloud cover will likely increase along and behind this feature, the column remains quite dry with PWATS only of 0.6-0.7 inches, and thus rainfall is not expected minus an isolated shower or sprinkle. This front will waver across GA Saturday into Sunday as the mid-level ridge gets suppressed, but will then wash out during Sunday thanks to increasing diffluence and rising thicknesses the latter half of the weekend. The toughest portion of this forecast then involves just how far south the front will slip, and whether the southern zones will cool much at all. WPC favors the front pushing south of Savannah, but MOS numbers suggest continued well above normal temps both days that far south. While Sunday`s forecast is easier - above normal everywhere as the front weakens, Saturday`s temps are more tricky. Will use a blend for temps Saturday, which create temps continued well above seasonable norms well south, despite a shift in winds to the NE. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Deep high pressure to prevail A powerful upper ridge will remain over the area into Wednesday before breaking down as an upper trough and associated surface cold front approach from the west. The front looks to weaken as it nears but it will likely lead to an increase in rain chances toward mid week as some deeper moisture moves into the area. Unseasonably warm temperatures will persist through Friday. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... As of 650 PM: Satellite and sfc observations indicated that a backdoor cold front will located west to east across Raleigh, NC. This front should drive southwest tonight, expected to reach Charleston and Berkeley Counties by 9z. The front is forecast to pass KCHS around 11z, possibly reaching KSAV during the mid morning hours, resulting in light NE winds. The primary forecast challenge will be the placement and timing of restrictive stratucu behind the front. Using CONSShort and forecast soundings, I will TEMPO MVFR ceilings between 11Z to 15Z. KSAV is expected to remain south of the restrictive ceiling deck. However, both terminals should see gradually increasing ENE winds through the daylight hours, with cloud decks near MVFR levels. Extended Aviation Outlook: VFR conditions should generally prevail through Tuesday, although flight restrictions will be possible each morning at KCHS/KSAV due to low clouds and/or fog. A cold front could bring some showers on Wednesday. && .MARINE... Light winds this afternoon and overnight will keep in only the 5 to 10 kt range, with seas of around 2 or 3 ft. Exception will be for AMZ374, where higher swells will bump seas up into the 3 to 5 ft range. Saturday through Wednesday: Gusty NE winds of 10-15 kts will envelop the waters Saturday as a back door cold front slides southward and stalls across GA. This front will wash out during Sunday allowing the gradient to relax, and while subtle shifts in wind direction are possible, a predominant NE wind will persist with speeds falling to 5-10 kts. Highest seas will occur during the strongest winds the first half of Saturday, reaching 3-4 ft, and will otherwise be rather placid at around 2 ft. Another tightening of the gradient is likely on Monday with an associated increase in winds/seas but again no Advisories are expected. A coastal trough could move in and/or set up Monday night as high pressure to the north slides east into the Atlantic before southerly winds and seas increase toward mid week with the approach of a weak cold front. && .TIDES/COASTAL FLOODING... Due to the a perigean full moon tide cycle, tides may approach 7 ft MLLW along the SC coast Saturday morning potentially requiring an advisory. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...NED SHORT TERM...ILM LONG TERM...ILM AVIATION...NED MARINE...ILM TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Quad Cities IA IL
931 PM CST Fri Jan 13 2017 .UPDATE... Issued at 920 PM CST Fri Jan 13 2017 Watching expansive area of precipitation over portions of E KS and W MO near to south of KC metro. Isentropic lift on 305K sfc depicts this current precip well, and supports this lifting across the far southern cwa after 07z through 12z. Have increased pops and expanded northward to near Fairfield, IA to Princeton, IL axis overnight. Overall the setup doesn`t look to dissimilar from a few nights ago when we had convection streaming across these same locations. What is different is moisture and magnitude of transport nowhere near as impressive for much, if any thunder. Nonetheless, still fairly steep mid level lapse rates within strong mid level baroclinic zone for likelihood of scattered showers with brief bursts of sleet and freezing rain potentially leading to slick conditions over portions of southeast IA, northeast MO into west central IL. && .SYNOPSIS... Issued at 315 PM CST Fri Jan 13 2017 18Z surface data had arctic high pressure over the western Great Lakes with a frontal boundary from Texas into the Tennessee Valley. Dew points were in the single digits above and below zero from the northern and central Plains into the western Great Lakes. Dew points in the teens and higher ran from the Great Lakes to the Gulf coast. && .SHORT TERM...(This Evening through Saturday) ISSUED AT 315 PM CST Fri Jan 13 2017 Quiet and dry conditions will be seen through sunset and into the early evening hours. The exception will be in the highway 20 corridor which might see some isolated flurries with a passing disturbance. Attention then turns to later tonight and Saturday. The morning balloon data showed a large and deep layer of cold, dry air across the area. Moisture will start surging into the area late this evening and overnight that will slowly moisten the dry layer at the surface. Based on trends from the RAP model, moisture will be slow to arrive this evening. Thus dry conditions are expected through midnight. There will likely be returns on the radar develop this evening. However, these returns will be clouds developing and/or virga. After midnight, the first wave will move from Missouri into southern Illinois. Per the RAP trends, the lower atmosphere slowly saturates. However, there is a large area of dry air above the fairly shallow moist layer. Additionally, the moist layer ends when temperatures get just above freezing aloft. Given this information, there are questions regarding the potential for precipitation occurring late tonight and into Saturday morning. Right now it appears that there is a low risk for a mix of sleet and possibly freezing rain south of a line from Galesburg, IL to just north of Memphis, MO. The cold temperatures and the depth of the cold air at the surface brings the possibility for the lower atmosphere to cool as precipitation begins. If this occurs, then the precipitation could be a mixture of sleet and snow. If there is any ice accumulation tonight, areas south of a Macomb, IL to Bible Grove, MO line would have the best chances of seeing a very light glaze. On Saturday, any lingering sleet, freezing rain, or snow in the far southern areas will end during the morning hours followed by temperatures climbing to around freezing. The remainder of the area will see dry conditions. .LONG TERM...(Saturday Night through Friday) ISSUED AT 315 PM CST Fri Jan 13 2017 Focus remains centered on the slow moving winter storm system that will lift through the area Monday and Tuesday. Latest model runs demonstrate critical differences in the timing and track of the surface low and exhibit an overall slowing trend over previous runs. Thus forecast confidence remains low and no changes were made to the winter storm watch headlines in place for Sunday into Monday morning. Overall, the ECMWF is more progressive with precipiation breaking out in the south late Saturday night, then becomes a slower, and more westerly outlier with the surface low tracking through central IA Monday night into Tuesday. The GFS and Canadian are faster with the low lifting out and also trend further east, passing over eastern IA/NW IL Mon night, reaching into lower MI Tuesday. Will continue with a low confidence blend for now, with the overall signal still showing freezing rain/sleet and possible light snow at the onset Sunday, changing the mix to all rain from south to north with the strong warm/moist advection and passing warm sector Sunday night through Monday morning. Saturday night: A cold and dry low level airmass remains in place associated with a 1034 mb plus high over southern MN/SW WI under a weakly confluent upper flow. The ECMWF remains the most progressive suggesting precipitation breaking out in the south by 12Z Sunday, while the more likely scenario suggests the northward advancing precipitation will stay to the south as the weak low level east to northeast flow continues a feed of dry air under weak forcing. Thus have only slight chance pops in the far south with low temperatures in the teens to low 20s. Little changes made to the main event Sunday and beyond with light ice accumulations of a tenth to possibly near a quarter inch in the far south/southwest before the changeover to all rain occurs late Sunday night through Monday morning. Latest models suggest areas north of I-80 may not see the mixed precipitation begin until Sunday evening. If current model trends continue, Sunday through Sunday evening timeframe would pose the greatest risk for ice accumulations in the south, while the late Sunday night and Monday periods may be at most risk for sleet and ice accumulations central and north. This is especially true if the slower, more westerly solutions bear out, keeping a low level feed of cold, dry air from under the exiting ridge into the area, under the deepening warm, moist advection aloft and stronger upper level forcing. Temperatures climbing into the 30s and 40s from late Monday through Tuesday should then quickly melt any accumulations. Tuesday night and beyond looks dry with above normal temperatures under a split flow aloft that keeps arctic air bottled up well to the north. && .AVIATION...(For the 00Z TAFS through 00Z Saturday Evening) ISSUED AT 537 PM CST Fri Jan 13 2017 Main concern tonight is the potential for pockets of lower MVFR cigs to develop at the terminals, as 925 mb winds turn e/se and attempt to advect pockets of low clouds and cigs 1200-1800 ft agl into the terminals from central IL. The MVFR cigs are fairly spotty and not widespread thus making confidence lower on occurrence. As a result, I have kept the TAFs all VFR through the period hinting at lower cloud potential with scattered MVFR bases mid evening into the overnight. Any MVFR cigs would appear to be fairly short-lived as 925 mb winds turn westerly late tonight, which would bring in drier air and shunt any lower cigs east of the terminals. Will continue to assess ob trends and amend if needed. E/NE winds around 5-10 kts will turn from N/NW on Saturday as reinforcing high pressure builds into the Upper Midwest. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...Winter Storm Watch from Sunday afternoon through Monday morning for Benton-Buchanan-Cedar-Clinton-Delaware-Dubuque-Iowa- Jackson-Johnson-Jones-Linn-Muscatine-Scott. Winter Storm Watch from Sunday morning through late Sunday night for Des Moines-Henry IA-Jefferson-Keokuk-Lee-Louisa-Van Buren-Washington. IL...Winter Storm Watch from Sunday afternoon through Monday morning for Henry IL-Rock Island. Winter Storm Watch from Sunday morning through late Sunday night for Hancock-Henderson-McDonough-Mercer-Warren. MO...Winter Storm Watch from Sunday morning through late Sunday night for Clark-Scotland. && $$ UPDATE...McClure SYNOPSIS...08 SHORT TERM...08 LONG TERM...Sheets AVIATION...McClure
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
836 PM CST Fri Jan 13 2017 .UPDATE... The dense cold airmass over North TX continues to spill deeper into the Northern Hill Country and Central TX, with the southernmost surge reaching just past ABIA at 8 pm. The next several hours will be tricky as at some point the front will be upended by the increasing nocturnal southerlies in advance of the approaching upper low. Early evening indications might suggest that the most aggressive NAM may be the winning model, but have blended in some more conservative RAP data through noon tomorrow. Main impacts to the overall forecast is earlier cooling near the front and overnight lows about 5-8 degrees cooler along and 20 miles inside the frontal zone. No attempts were made to speculate on any impacts the frontal surge will have on highs Saturday as radar velocity data shows the frontal inversion to be very shallow. && .PREV DISCUSSION... /ISSUED 558 PM CST Fri Jan 13 2017/ AVIATION... /00Z TAFS/ The slow moving shallow cold front will be the main challenge to impact the TAF periods, especially at AUS where radar imagery suggests the boundary entering the northern 5 mile vcnty ring. Conditions around AUS could thus vary greatly through the next 12 to 18 hours with a slightly higher presence of light shower activity than the other taf locations. Prevailing ifr conditions are expected south of the front for all sites for much of the late evening and early morning hours. Close to daybreak, skies could drop into lifr categories, especially at AUS, with showers expected to increase mainly from 08z to 18z. Mixing should be a gradual process, but will continue with a slightly more optimistic than model guidance trends for vfr skies by around 21Z. The front is expected to mix northward to no longer impact TAF sites by 21Z, but a slightly more easterly wind may result from the modified pressure fields. This could lead to lower cigs and more shower activity in TAF updates, as some of the finer resolution models show more frontal influence east of I-35. PREV DISCUSSION... /ISSUED 331 PM CST Fri Jan 13 2017/ SHORT TERM (Tonight through Saturday Night)... The boundary of the shallow cold front has progressed very slowly southward this afternoon as evident off GRK radar and area surface observations. The front is just south of a Llano to Georgetown line. Have followed closer to the RAP and NAM12 over the next 12-18 hours with the front, and some additional southward progression is possible tonight before the front moves back north Saturday afternoon. High temperatures will be tricky for northern areas Saturday, depending on how far south the front. A continued warm night for most of the area south of the front. Isolated to widely scattered showers will be possible through the short term. LONG TERM (Sunday through Friday)... An upper level low will lift northeast out of Mexico into far West Texas on Sunday and then north through the Panhandle and into Kansas Sunday night and Monday. Large scale ascent will overspread the western CWA Sunday afternoon with the approach of the low. Showers and thunderstorms are expected to develop across the western CWA as the ascent overspreads the area and interacts with an eastward advancing Pacific cold front. CAPE values of around 1000 j/kg and deep layer shear of 40-50 kts should support a strong to severe threat as the storms develop Sunday afternoon. The severe threat should continue east into the central CWA Sunday evening as the front progresses east. A 40-50 kt low level jet and 0-1KM SRH values of 200-300 m^2/s^2 will support a threat for an isolated tornado risk Sunday afternoon and night. In addition, as the upper level low lifts more northeast to north the mean flow becomes more parallel to the front. This in combination of PW vales up to 1.4" could support a threat for locally heavy rainfall across central and eastern counties Sunday night into Monday morning. Eventually the front slides through eastern counties Monday evening. As the upper level low opens and ejects north additional energy digs back into the base of the trough Monday into Tuesday. This may continue a chance for rainfall Monday night through Tuesday. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 57 72 60 74 62 / 20 30 20 50 80 Austin Bergstrom Intl Airport 60 73 61 75 62 / 20 30 20 40 80 New Braunfels Muni Airport 63 75 61 75 63 / 20 20 20 40 70 Burnet Muni Airport 51 68 58 70 58 / 30 30 20 60 90 Del Rio Intl Airport 65 74 63 74 53 / 50 30 40 60 60 Georgetown Muni Airport 51 70 58 72 60 / 30 30 20 50 90 Hondo Muni Airport 65 75 62 75 61 / 30 30 20 50 70 San Marcos Muni Airport 63 74 61 76 63 / 20 30 20 40 70 La Grange - Fayette Regional 64 76 62 75 65 / 20 20 20 30 50 San Antonio Intl Airport 65 75 62 75 62 / 20 30 20 50 70 Stinson Muni Airport 67 77 63 76 64 / 20 30 20 50 60 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Mesoscale/Aviation...Allen Synoptic/Grids...Oaks Public Service/Data Collection...30
Area Forecast Discussion
National Weather Service Fort Worth TX
743 PM CST Fri Jan 13 2017 .UPDATE... The shallow cold airmass in place on the north side of an arctic front resides below 925 mb and continues to be a challenge for guidance. The boundary continues to sag south over Central TX and may not begin to lift back to the north until tomorrow. The HRRR seems to be doing a respectable job with the shallow frontal layer, eventually stalling the boundary late this evening and keeping it quasi-stationary along the southeast border of the CWA through much of Saturday morning. Some changes to the temperature forecasts were required based on the expected position of the front. Temperatures will be kept fairly steady overnight, with an increasing trend beginning mid to late morning Saturday. The good news is that even if it cools another couple of degrees tonight, all precipitation across the CWA overnight should still remain in liquid form. We will need to keep an eye on the northwestern-most counties where some lower and middle 30s are being reported, but since precip is falling through such a large warm layer, even if a few spots dropped to 30-32 degrees there would likely only be minor accumulations on elevated surfaces. 30 && .AVIATION... /ISSUED 610 PM CST Fri Jan 13 2017/ A frontal boundary extended south of a KF44 (Athens) to KT35 (Cameron) to KGTU (Georgetown) line as of 23Z (5 PM CST). As can be seen on the KGRK radar, this boundary is continuing to slowly move southward. Expect north flow to prevail at all of the TAF sites for the next 36 hours. All of the TAF sites are already IFR and some LIFR conditions are possible overnight and Saturday morning. Areas of fog and patchy drizzle are possible through Saturday. Scattered showers are expected mainly during the afternoon and evening Saturday and an isolated thunderstorm will be possible. More widespread showers and thunderstorms are expected Sunday. 58 && .PREV DISCUSSION... /ISSUED 400 PM CST Fri Jan 13 2017/ Two distinct airmasses are currently in place across Texas this afternoon with a nearly stationary frontal boundary marking the transition from warm and humid to cold and damp. At this hour the front is ever so slowly continuing to slide south as indicated by the Granger radar with the boundary located across the northern half of Milam county. The front stretches northeast from there and is very near Athens then extends to just south of Texarkana. North of the front...temperatures are in the 30s and 40s with north winds and areas of light rain and drizzle. South of the front... temperatures are in the 70s and 80s. The cold front is very shallow across North Texas with the 12Z Fort Worth sounding showing a depth of only around 1000 feet. Southerly winds are noted on both the Granger and Fort Worth VAD wind profiles at 2000 feet. This low level warm moist advection above the cooler surface air has resulted in an area of light to moderate rain and drizzle which continues to move north through the area this afternoon. This initial wave of ascent and moisture advection will continue northward through this evening and we should see a gradual decrease in the coverage of precipitation through tonight. PoPs will be highest generally along and north of I-20. Surface observations show that temperatures are in the upper 20s and lower 30s across central and southern Oklahoma with mid 30s across our northwest counties. There is some weak surface cold advection but this should become neutral later this evening. With strong southerly winds above the shallow front...the front itself should become completely stationary or may begin to drift back to the north slowly. Overnight temperatures are likely not to cool much more...and may even rise a couple of degrees overnight. Concerning any potential freezing rain in our area...temperatures are unlikely to fall to or below freezing anywhere in our area given the lack of more robust low level cold advection so no wintry precipitation is expected. On Saturday...the frontal boundary will continue to lift north and will continue to be modified by warm southerly flow. Moderate warm advection will continue although it does appear that some dry air will impinge upon the area from the east late in the day. This should generally keep rain chances lower than today. There will be sufficient moisture across our northwest counties to support some slightly higher rain chances. By Saturday night into early Sunday morning...the powerful upper low over the southwest will be approaching far west Texas. This will allow a surface low to develop across west Texas and low level flow across our area to strengthen and back to the southeast. Large scale forcing for ascent will increase through the day Sunday with widespread showers and a few thunderstorms developing across west Texas. Areas west of I-35 will have the best rain chances late Sunday with a line of showers and thunderstorms moving across the rest of North Texas on Sunday night. PoPs will be near 100% Sunday night into early Monday morning across the region...with most areas picking up more than an inch of rainfall. There will be a threat for locally heavy rainfall in some areas...especially east of I-35 through Monday but the overall flash flood threat appears low at this time given that the main line of convection is expected to move through rather quickly. Concerning the severe weather potential... As the upper low gets closer Sunday night...wind fields will strengthen resulting in large curved hodographs indicative of impressive 0-1 and 0-3km shear values across North Texas. This occurs as a strongly forced line of convection moves through the region. The major limiting factor to a more impressive severe weather setup is the lack of any substantial low level instability. Forecast soundings from the most aggressive guidance indicates MUCAPE of around 500-700 J/kg however most of this seems to be the result of steepening lapse rates with the approach of the upper low. Very little instability is noted in the 0-3km layer which suggests a limited severe weather threat at this time. So...given the strong shear profiles...there will be an isolated tornado threat with the more robust updrafts...but at this time a widespread severe weather event does not appear likely. We will continue to monitor this over the next day. Precipitation should end from west to east during the day on Monday with cooler temperatures filtering into the area on Tuesday. A lingering piece of shortwave energy will spread over the area Tuesday night with continued low rain chances. Dunn && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 40 60 53 67 56 / 30 30 20 40 100 Waco 44 67 57 70 59 / 30 20 20 50 100 Paris 46 61 54 68 59 / 40 30 20 20 90 Denton 39 55 51 65 52 / 40 40 20 50 100 McKinney 41 59 52 66 56 / 30 30 20 30 100 Dallas 41 61 55 68 58 / 30 30 20 40 100 Terrell 45 65 55 68 59 / 30 20 20 30 100 Corsicana 47 69 56 71 60 / 20 20 20 30 100 Temple 47 69 58 71 59 / 30 20 20 50 100 Mineral Wells 37 56 51 65 49 / 40 40 20 70 100 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 58/30
Area Forecast Discussion
National Weather Service Lincoln IL
906 PM CST Fri Jan 13 2017 .UPDATE... Issued at 855 PM CST Fri Jan 13 2017 No major changes to going forecast and headlines this evening. First wave of rain and freezing rain has shifted into extreme southeast Illinois and should move out of our area over the next hour. Our attention now turns to another band of freezing rain that is forecast to track out of Missouri late tonight and into our area after 08z and continue on and off through the morning before the precip starts to get shunted to our southeast in the afternoon. RAP/HRRR/and latest NAM showing this wave for the early morning hours tracking further north than our initial wave that focused in areas south of I-72 today. Model consensus suggests a tenth to locally two tenths of an inch may occur with this second wave, especially along a Taylorville to Mattoon to Paris line with lighter amounts, generally less than a tenth of an inch up to the I-74 corridor with the trend for trace amounts further north. As mentioned above, the precip should push out of most of the area, except the far southeast by afternoon. By that time, it appears our surface temperatures may be close to our just above the freezing mark which should melt any additional ice the falls Saturday morning. Have bumped the POPs up further north to reflect the northward trend in models with the next wave of freezing rain. We should have the updated ZFP out by 915 pm. && .SHORT TERM...(This evening through Saturday) ISSUED AT 258 PM CST Fri Jan 13 2017 Will change the winter storm watch over central part of CWA to a freezing rain advisory tonight through Sunday morning. So a freezing rain advisory will be in effect from Schuyler, Mason, Logan, DeWitt, Champaign and Vermilion counties southward. Winter Storm watch continues north of there from midnight Sat night thru Sunday night. A frontal boundary over southeast TN into southern AR and central Texas was causing overrunning of light freezing rain and sleet into areas south of Taylorville to Paris line at mid afternoon where temperatures were mostly 30-32F with Lawrenceville up to 33F. Colder temperatures in the mid to upper 20s north of Lincoln. Mostly cloudy to overcast skies over CWA at mid afternoon. Strong 1045 mb arctic high pressure over central WI and sprawled across the Great Lakes region was giving a ne flow of cold air into central IL. Still some forecast model differences with handing qpf fields through Saturday even with the short range/high resolution models. The HRRR models has area of light freezing rain and sleet diminishing over southeast IL by 03Z/9 pm this evening with just a few smaller patches of light qpf thereafter as far north as Canton and Bloomington. The RAP13 model also diminishing mixed pcpn over southeast IL but not until late evening and then develops expanding area of light qpf after 2 am from Peoria south. The NAM12 model diminishing light qpf in southeast IL early this evening, and then spreads/develops light qpf ne toward I-72 during overnight. With stronger arctic high pressure nearby over WI, will keep northern CWA drier tonight into Saturday. Will bring chance of light freezing rain northward into central CWA during the evening with likely pops in southeast IL. Models then diminish qpf from nw to se during Saturday especially north of I-70. Light rain will also becoming more likely in southeast IL by Saturday Saturday afternoon. Ice accumulations up to a tenth inch from I-72 south tonight into Sat morning (locally one to two tenths along I-70) with less amounts se of I-70 due to milder air and also north of I-72 in drier air. Lows tonight range from lower 20s nw of IL river, to 30-32F in southeast IL from I-70 south. Highs Saturday range from lower 30s north of I- 72 to 35-37F in southeast IL. ENE winds will stay fairly light during this weekend. .LONG TERM...(Saturday night through Friday) ISSUED AT 258 PM CST Fri Jan 13 2017 A lull in the freezing rain threat will exist at the beginning of the forecast period across most of the forecast area, with the better chances just to our west/south across Missouri and far southern Illinois. Our attention to start next week turns to the vigorous upper low that is currently spinning off the southern California coast. This feature will eject northeast toward the area Sunday into Monday, accompanied by a surface low and more widespread precipitation than is in our vicinity right now. The initial surge of precipitation associated with the southwest system will arrive late Saturday night into Sunday. Initially, our local surface temperatures will be cold enough for freezing rain. As the precipitation returns, moisture depth is too shallow/warm for ice crystals, so freezing rain is expected at the onset. Then, as deeper moisture and cloud ice returns, a period of sleet/snow is possible. However, the sleet and/or snow should not last long as a deeper elevated warm layer develops. This signals a south to north return to freezing rain on Sunday into Sunday night. However, as surface winds turn more southerly later Sunday into Monday, temperatures will warm enough for rain. This system does not exit the area until later Tuesday, and rain chances will linger until the system departs. Hazardous travel condtions are expected from time to time into Monday with the periods of freezing rain anticipated. However, a significant ice storm does not look likely due to the relatively low rainfall amounts that occur with sub-freezing temperatures, as well as the diurnal melting that could occur in many areas on trees and power lines. Once the current system finally leaves the area early next week, the rest of the week should be fairly quiet weather wise with warmer than normal temperatures. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 535 PM CST Fri Jan 13 2017 Initial wave of freezing rain was located just south of SPI and DEC early this evening with a temporary lull in the precip further west and south. We expect light freezing rain to develop over central Mo after 04z and spread into parts of central IL after 08z and be with us for about a 6 to 8 hour period before all the precip gets shunted to the south by afternoon. We should also see a gradual deterioration in the cigs later this evening from south to north, although some MVFR cigs pushed into PIA and BMI earlier today from the northeast. Further north towards I-74 there is quite a bit of dry air in the low levels so any precip to our south should stay to the south thru the evening with the threat for precip shifting closer to our northern TAF sites Saturday morning. Most areas should see IFR cigs with some lower vsbys in fog as well as we head thru the morning on Saturday with some improvement in cigs/vsbys during the afternoon, but still looking like mainly MVFR conditions at that time. Winds will be northeast to east at 8 to 15 kts tonight and then back more into a north to northwest direction on Saturday with speeds of 5 to 10 kts. && .ILX WATCHES/WARNINGS/ADVISORIES... Freezing Rain Advisory until noon CST Sunday for ILZ040>057- 061>063-066>068-071>073. Winter Storm Watch from late Saturday night through late Sunday night for ILZ027>031-036>038. && $$ UPDATE...Smith SHORT TERM...07 LONG TERM...Bak AVIATION...Smith
Area Forecast Discussion
National Weather Service Jackson MS
936 PM CST Fri Jan 13 2017 .UPDATE... Updated for evening discussion. && .DISCUSSION... Anomalously warm weather continues across the ArkLaMiss as a 590 dam subtropical ridge remains centered over the SE CONUS. This allowed for two more daily record highs to fall/tie today at HBG and TVR. A few shallow isolated showers formed this afternoon beneath a stout mid-level inversion, but quickly dissipated. A stalled frontal boundary remains draped across the NW portion of our CWA with current temps as of 3z in our NW in the low 50s and even upper 40s, while the remainder of the area remains mild with temps in the upper 50s/low 60s. For the remainder of the evening, the main forecast concern will be the potential for areas of fog with visibilities less than 1/4 mile possible. There has been some disagreement between guidance as to where the best fog potential will be with the HRRR and GFS hitting the NW hard, while the NAM wants to show the best potential in the east. Opted to go with the HRRR solution, as it is likely handling the advection of drier air from the east the best. While some degree of fog is still expected area wide, the best coverage will be along the HWY 82 corridor down to TVR along the stalled frontal boundary where moisture pooling, low dewpoint depressions, and low condensationpressure deficit values are located. Therefore, went ahead and issued a dense fog advisory for north and west portions of the CWA. Right now, it appears the drier air, characteristic of low 50s/upper 40s dewpoints, will preclude greater fog coverage in the SE, however trends in this area will be monitored and the current dense fog advisory may have to be expanded if conditions become more favorable for widespread fog development. Otherwise, lowered overnight min temps, especially in the NW in the vicinity of the stalled frontal boundary and in the east where better cooling is expected to occur. /TW/ Prior discussion below: Tonight through Saturday, An anomalously warm weather pattern for the ArkLaMiss will continue into the weekend as a strong 590 DM subtropical ridge remains centered over the northeast Gulf of Mexico. A few showers that developed earlier today have mostly dissipated. The primary weather concern in the near term will be for redevelopment of fog late tonight into Saturday morning given the warm, moist boundary layer above the relatively cool ground. While we are likely to see fog in most locations, there is some uncertainty with "dense" fog development due to mixing of a shallow surface front over the Delta region and some potential for drier air to advect in from the east over the Pine Belt region. These uncertainties are reflected by a variety of solutions in the high- res near term guidance, and after coordination with surrounding offices, have decided to hold off on a dense fog advisory. For now, have broad brushed a limited threat for dense fog in the HWO and will allow future shifts to better assess areas of greater dense fog potential. Otherwise, look for any fog to burn off by late Saturday morning with a variable amount of cloud cover to follow along with well above normal temperatures. Slightly cooler but still above normal temperatures associated with shallow cooler air over the upper Delta region can be expected. /EC/ Sunday through Friday: The remainder of the weekend should continue to be warm across the forecast area as a low pressure system lifting northeastward out of the High Plains strengthens warm, onshore flow across our region. The upper-level ridge should begin to weaken slightly in advance of the approaching upper low as we head into the new work week, but its effects will continue to be felt with max temperatures in the mid to upper 70s area wide on Sunday and Monday. Meanwhile a deepening upper-level trough moving into central portions of the country, with a series of shortwaves interacting with it through the middle of the week. Models have continued to struggle with the finer details of this pattern - speed and strength of the shortwaves, particularly. Therefore confidence on how fast the overall trough axis moves across our region remains low. A general consensus of deterministic and ensemble guidance continues to suggest a slow moving upper trough edging over Louisiana and Arkansas Monday night, with a cold front slowly advancing into our western parishes counties sometime on Tuesday. Moisture advection ahead of this system will be concentrated along the front, and could result in some periods of heavy rainfall for our area. Tuesday afternoon into Tuesday night continues to look like the favored time period for heavier rainfall somewhere in the vicinity of the Mississippi River. Model runs today show enough slow movement of the trough throughout the day Wednesday that any concerns for flooding remain low. Though details are murky at this point, models agree that the next trough will quickly move into the western CONUs as we head into the second half of the week. Have continued slight chance to chance POPs through the end of the forecast to account for possible periods of showers or thunderstorms ahead of that next trough. && .AVIATION... 00Z TAF discussion: Mostly VFR conditions are occurring this Friday evening, but GLH has dropped to MVFR ceilings. Expect more MVFR to IFR ceilings to occur this evening into the overnight hours. Patchy fog will again be possible across the area with some potential for dense fog in northern locations. Will continue to monitor and amend any TAFs if needed, but expect the dense fog to occur closer to daybreak. /28/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 53 75 53 75 / 2 5 3 5 Meridian 50 75 51 75 / 1 4 3 5 Vicksburg 54 75 53 75 / 1 7 4 7 Hattiesburg 51 76 53 75 / 1 5 3 8 Natchez 56 75 55 75 / 3 6 3 10 Greenville 49 70 52 71 / 1 16 10 7 Greenwood 53 73 52 73 / 1 13 7 6 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...Dense Fog Advisory until 9 AM CST Saturday for MSZ018-019- 025>042-047. LA...Dense Fog Advisory until 9 AM CST Saturday for LAZ007>009-015- 016. AR...Dense Fog Advisory until 9 AM CST Saturday for ARZ074-075. && $$ TW/NF/28/EC
National Weather Service Jackson KY
1005 PM EST Fri Jan 13 2017 .UPDATE... Issued at 1005 PM EST FRI JAN 13 2017 Dense fog is setting up on the ridges of eastern Kentucky along with development just to the southwest of the CWA - and indications in the HRRR and CONSShort for low vis in these areas through the night. Accordingly, have updated the forecast to include this along with issuing an SPS in conjunction with LMK and OHX. with this updated also fine tuned the rain chances through the rest of the night along with a tweaking to T and Td grids per the latest obs and trends. These have been sent to the NDFD and web servers. Along with the SPS an update to the ZFP and HWO have been issued. UPDATE Issued at 745 PM EST FRI JAN 13 2017 00z sfc analysis shows the cold front through the southern portion of the CWA with patches of rain of a scattered to numerous nature passing through the breadth of eastern Kentucky. The amount of moisture in the air is keeping the clouds rather low through the night and into Saturday along with patchy fog. Currently the front shows up quite well in the obs with temperatures varying from the lower 50s in the far southeast to the upper 30s/low 40s north. Dewpoints are generally within a degree or two of the dry bulb temperatures while winds are mostly from the northeast at 5 to 10 mph. Have updated the grids through the night to reflect the timing and placement of the PoPs across the area based on current radar trends and consensus model guidance. Also loaded in the latest ShortBlend temp/dewpoint guidance through 12z Saturday and tweaked them for the current obs and trends. The updated grids - including beefed up amounts of fog - have been sent to the NDFD and web servers. && .SHORT TERM...(This evening through Saturday night) Issued at 316 PM EST FRI JAN 13 2017 An east to west oriented line of precipitation continues to track across the Ohio Valley into much of central and northern Kentucky. This will remain in the liquid phase across all of eastern Kentucky as temperatures will hold in the mid-upper 30s across the Bluegrass region with warmer readings farther south. This is thanks to surface high pressure sliding across the Great Lakes and lower Canada keeping a more substantial cold dome from building south into the Coal Fields. Upper level features further support above freezing surface temperatures as an upper high nudges north across the Gulf coast into the western Atlantic with a trough traversing the St. Lawrence Valley, allowing for today`s earlier frontal/moisture convergence boundary to surge back north toward the Ohio River, thus ushering warmer air back in aloft. Have gone ahead and also inserted patchy fog into the forecast given the plethora of low level moisture and overall light winds in place. After a lull in the more widespread rain for a brief period tonight, a band of precipitation will develop across the Ohio Valley early Saturday as another upper trough skirts the western shores of Hudson Bay, subsequently sending the frontal boundary back toward eastern Kentucky. This will bring numerous to widespread rain showers back in through the day. At the same time, cooler air will once again infiltrate the Commonwealth, although temperatures near and above 40 degrees will keep only rain in the offing. In fact, temperatures near the Tennessee border may again reach the mid 50s without a significant southward push of colder air behind the front. Rain chances will decrease from north to south through the evening and overnight into Sunday morning along the front, but rain showers will remain likely with the front in proximity to the region in combination with a saturated airmass. .LONG TERM...(Sunday through Friday) Issued at 200 PM EST FRI JAN 13 2017 Very mild and damp weather will continue through next week. To begin the period, a deep layer of low level moisture will be in place with the frontal zone still over the region. This will provide lots of clouds and steady temperatures from Sunday through Monday morning. Moisture profiles are also very supportive of a prolonged period of drizzle into Monday morning. With this said, models continue to run too low with the rain chances and have opted to go into the likely range for rain chances, staying above model guidance. This is a situation, where models are never high enough on the rain chances. Heights will finally start to build on Monday as a sharp shortwave trough helps to develop a strong area of low pressure across the central plains. This will send the nagging boundary off to the north with eastern Kentucky breaking into the warm sector. This will send temperatures much higher into the 60s, setting up another very warm mid January day. We could have a few spotty showers pop up in the warm sector on Monday, most likely from the Cumberland Plateau up across central Kentucky. With the deep system developing out to our west, models still showing uncertainty heading into the Tuesday and Wednesday time period with the strength of the system likely dictating how our weather unfolds. Either way confidence is fairly high a frontal boundary will get pushed into the region Tuesday or Wednesday, providing another good chance of rain. With deep southwesterly flow in place and a frontal boundary lined up with the flow, we will have to watch the potential for locally heavy rain somewhere in the Ohio River Valley. Right now, models tend to be targeting areas more in central Kentucky for heavier rain potential, but with lots of details yet to be sorted out, this could easily shift east or west. Certainly something to monitor heading into next week, given the saturated ground conditions. We may dry out Wednesday night or Thursday, but another system may follow quickly on the heels of the midweek system. Thus, rain chances will continue into the end of the week. One thing is for sure, the mild weather isn`t going anywhere through the end of next week. In fact, several more days of highs in the 60s will be possible from Tuesday through Thursday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 700 PM EST FRI JAN 13 2017 LIFR/IFR conditions remain in place across the area, for the most part. The band of rain across the area will continue - more off than on - through the night and into Saturday - with more in the way of convection expected from midday Saturday into the afternoon. Visibilities will be variable through this time depending on the movement and impact of the showers on each site. Due to this, ceilings will stay IFR/LIFR through Saturday morning and into the afternoon. Winds will be generally light from the northeast through the period. Note: icing concerns still look to remain north of all JKL terminals through the weekend. Pilots flying west into the Missouri Valley or north toward CVG/CMH need to be aware that icing potential will greatly increase tonight into Saturday. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...GUSEMAN LONG TERM...KAS AVIATION...GUSEMAN/GREIF
Area Forecast Discussion
National Weather Service Norman OK
943 PM CST Fri Jan 13 2017 .DISCUSSION... Have made minor adjustments to temperature, rainfall/ice accumulation, and related elements to account for the latest observations and short-range guidance. No changes have been made to the Warning/Advisory configuration. The HRRR seems to be doing quite well with rainfall forecasts. As such, it appears that the greatest rainfall in central Oklahoma will occur around/after sunrise tomorrow, with only light amounts overnight. Heaviest rainfall overnight and early Saturday should occur along the wet- bulb freezing line, which will move very little overnight, roughly from Wichita Falls to Ada to Holdenville. && .PREV DISCUSSION... /issued 559 PM CST Fri Jan 13 2017/ DISCUSSION... AVIATION... Freezing rain and rain will persist through Saturday over most of Oklahoma and northern Texas. IFR conditions become common. PREV DISCUSSION... /issued 332 PM CST Fri Jan 13 2017/ DISCUSSION... Freezing rain and ice accumulations continue to be the questions this forecast. Small area of freezing rain in north central OK this afternoon will continue to lift NE out of the area. Radars show another area of precipitation moving into the area from Texas. This precipitation will move into areas where temperatures are at or near freezing leading to another round of icy weather. Temperatures are expected to remain fairly steady tonight so areas that are at or below freezing right now will likely remain that way tonight. Models show another round of heavier precipitation late tonight into Saturday morning across portions of central OK. Where exactly this area of heavier freezing rain sets up will have an impact on ice accumulations overnight into the morning. Right now, the models are showing this area along or near the I-40 corridor which includes the OKC metro area. With this in mind, the Ice Storm Warning has been extended southward and some adjustments were made to the freezing rain advisories. Models then show another round of heavier precipitation affecting NW/N portions of the fa Saturday afternoon and night. The freezing line is still expected to begin to slowly shift northward Saturday and Saturday night so even though precipitation chances will continue Saturday some locations will only experience a cold rain instead of freezing rain. How soon and how quickly the freezing line lifts could have an affect on how much ice accumulation occurs in a location. The good news is that once temperatures go above freezing this weekend, they will likely remain above freezing except for maybe parts of N OK. Temperatures are expected to warm to above freezing everywhere on Sunday. Models show the upper low moving across the region Sunday into Monday leading to fairly widespread rain showers and some thunderstorms. A few strong to severe storms may also be possible in parts of southern OK and north TX Sunday night into Monday. The precipitation is expected to finally end on Monday. After Monday the forecast remains dry with near or above average temperatures next week. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 28 35 34 50 / 70 80 70 60 Hobart OK 27 35 34 49 / 60 80 60 80 Wichita Falls TX 30 42 40 59 / 70 70 40 80 Gage OK 25 31 29 39 / 40 90 80 80 Ponca City OK 28 33 31 46 / 50 80 80 50 Durant OK 35 47 45 62 / 50 40 30 50 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...Ice Storm Warning until 6 AM CST Sunday for OKZ004>020. Freezing Rain Advisory until midnight CST tonight for OKZ032-039- 042-044-045. Freezing Rain Advisory until 6 AM CST Saturday for OKZ031-037- 040. Ice Storm Warning until 6 PM CST Saturday for OKZ021>030. Freezing Rain Advisory until 6 PM CST Saturday for OKZ033>036- 038. TX...Freezing Rain Advisory until midnight CST tonight for TXZ086>090. Freezing Rain Advisory until 6 AM CST Saturday for TXZ083>085. && $$ 23/09
Area Forecast Discussion
National Weather Service Shreveport LA
950 PM CST Fri Jan 13 2017 .DISCUSSION... At 0330z, a quasi-stationary surface front was located from Northwest Smith County, to near Pittsburg, TX, and then generally eastward along the Arkansas/Louisiana border. Highest rain chances will continue to be north of Interstate 30 as precip develops across North Texas and moves northeast. Farther south, scattered showers have been trying to develop across Deep East Texas and Central Louisiana in the warm sector. These showers are moving north. These trends should continue through the overnight hours, so no changes were made to the PoP grids. Forecast soundings suggest the potential fog development across much of the area, especially within the warm sector after midnight. The HRRR appeared to have a good handle on the frontal position and the resulting temperatures and dewpoints. Therefore, temps were adjusted to closely follow the HRRR through the remainder of the night. Updated text products have been sent. /09/ && .PREV DISCUSSION... /issued 922 PM CST Fri Jan 13 2017/ AVIATION... For the 14/00Z terminal forecast period, all sites will begin with prevailing VFR flight categories with a gradual lowering of the bases and lowering of the visibilities to MVFR during the overnight hours with IFR and below flight categories after 14/07Z. Parts of East and Northeast Texas and Southwest Arkansas will be in near a frontal boundary that will aid in the development of rain and showers. IFR/LIFR persisting through around 14/15Z before improving to MVFR. Surface winds light East to Southeast to prevail through the terminal forecast period with Northeast winds 3-7 knots for Southwest and South Central Arkansas and Western sections of East and Northeast Texas in wake of the nearly stationary front near the Arkansas/Louisiana border to near Gilmer texas and to the west of an Idabel Oklahoma to Tyler and Palestine Texas line. PREV DISCUSSION... /issued 345 PM CST Fri Jan 13 2017/ DISCUSSION... Stalled cold front remains just along the wrn and nrn CWA boundaries of E TX/SE OK/SW AR this afternoon. Light shwrs continue in the warm sector, but have seen very little convection focused along the boundary. The front is fcst to begin to move back nwd tonight as low pressure in the plains deepens. SW flow aloft over the top of a very unseasonably warm and moist boundary layer will continue to allow for isold to sct shwrs through the weekend. Rain chances will increase into early next work week, as the upper low off the coast of srn CA moves into W TX Monday. While this system may pose a severe threat to areas of W and Central TX, that threat will greatly diminish as the upper low dampens and lifts newd over central OK. The ewd progression of the front will slow significantly, and the loss of strong upper level support and lack of overall instability will limit severe potential with the tstms. Front/upper low looking a bit more progressive with this package, which has cut down on the qpf quite a bit from earlier packages. Rain looks to move out late Tuesday/early Wednesday, with little to no change in airmass. Secondary upper low will move in on the heels of the early-week system, and will bring chances for rain back to the region for the latter half of the work week. Models a bit inconsistent on this feature, so stayed with conservative, low-end PoPs attm. Unfortunately for those who enjoy seasonable January temperatures, we will remain above normal, and in most cases well above normal, for the entirety of the fcst pd. /12/ && .PRELIMINARY POINT TEMPS/POPS... SHV 63 75 56 74 / 20 20 20 20 MLU 56 75 54 74 / 20 10 20 20 DEQ 51 64 53 67 / 50 40 30 30 TXK 52 67 54 70 / 30 30 30 20 ELD 52 70 52 71 / 30 20 20 20 TYR 55 74 57 72 / 20 20 30 20 GGG 62 74 57 72 / 20 20 30 20 LFK 63 77 59 74 / 20 10 20 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 09/06/12
Area Forecast Discussion...UPDATED
National Weather Service SAN ANGELO TX
955 PM CST Fri Jan 13 2017 .UPDATE... Temperatures have slowly dropped to the freezing mark at some locations across the far north/northwest part of west central Texas. Temperatures are expected to remain nearly steady overnight. Radar shows the development of sattered light rain showers across the eastern half of the Big Country, mostly east of a Haskell to Abilene line. Movement of the showers is to the north. The coverage of showers overnight should remain limited enough to keep PoPs in the chance category. With these considerations, making an update to the forecast to carry expand the mix of light rain/light freezing rain to encompass the area north of a Sweetwater-Albany line. May also have some patchy light fog/drizzle or a little freezing drizzle where temperatures are at or just below freezing. Having mentioned this, precipitation is expected to remain light and patchy/scattered overnight. With temperatures holding steady and not expected to drop farther overnight, no travel problems are anticipated. But will monitor the situation closely and update if needed. Latest update to the forecast products will be out shortly. && .PREV DISCUSSION... /issued 815 PM CST Fri Jan 13 2017/ UPDATE... The cold front has sagged a bit farther south than previously anticipated, and was near the southern border of Sutton and Kimble Counties this evening. The 18Z NAM and latest HRRR indicate that the front will stall, but will not begin to move back to the north until around midday Saturday. Temperature, wind and dewpoint adjustments were made to account for the farther southward progress of the front. Also made upward adjustments to sky cover, given the current and expected trends with widespread cloud cover. PREV DISCUSSION... /issued 552 PM CST Fri Jan 13 2017/ AVIATION... /00Z TAFS/ Look for very challenging flight weather, during the next 24 hours. A weak cold front currently lies along or near a line from Sonora to Junction. Warm and moist air, moving over colder air at the surface, will continue to produce low ceilings and perhaps light showers, during the next 24 hours. Models indicate little if any potential for improvement. By 12Z tomorrow, expect IFR ceilings to dominate all of West Central Texas. PREV DISCUSSION... /issued 330 PM CST Fri Jan 13 2017/ SHORT TERM... (Tonight and Saturday) An upper level low just off the CA coast continues to move southeast toward the northern Baja Peninsula. This low will move into the central Baja Peninsula by Saturday afternoon, keeping southwest flow aloft over our area, which will result in weak shortwave energy passing over the area through tomorrow. The cold front that moved through the Concho Valley overnight and this morning looks to have stalled roughly along a line from Barnhart to Menard to Mason. The front is expected to either remain stalled tonight or continue very slowly through Saturday morning before beginning its progress back to the north tomorrow. For tonight, the boundary will serve as a stark delineation between cooler overnight lows to the north and warmer lows along the I-10 corridor. As the upper level low approaches through tomorrow, southerly flow just off the surface will increase, lifting moist unstable air over the top of the cold surface air. This, along with passing weak shortwaves will allow for scattered showers to develop during the overnight hours tonight. On Saturday as the upper low approaches, surface pressure falls will occur across west Texas and the desert southwest. This is expected to turn winds to a more southeasterly direction, and begin moving the cold front northward again. Exactly how far north the front will make it is still uncertain, but will keep the warmer temperatures generally south of I-20 for now. There will be a continued chance for isolated to scattered showers through Saturday, and with additional heating, a few thunderstorms cannot be ruled out, although severe weather is not expected. LONG TERM... (Saturday night through Friday) A cold front will be stalled across the central portions of West Central Texas Saturday evening, then slowly begin to lift north Sunday morning into Sunday afternoon. Highs on Sunday will generally be in the 60s, as abundant cloud cover, scattered showers, and isolated thunderstorms are expected, ahead of an approaching upper level low. This upper level low will be located across far West Texas Sunday afternoon, then swing across the Texas Panahandle Monday morning. As this feature approaches, large scale lift will result in increasing showers and thunderstorms across West Texas Sunday morning, then spread east into West Central Texas Sunday afternoon and evening. During this time frame, SBCAPE values will increase to 500-700 J/KG while 0-6 KM Bulk Shear values increase to 50 to 70 knots. A few strong to severe thunderstorms will be possible, with large hail and damaging winds being the main concerns. Rain chances will decrease from west to east during the evening hours, with most of the convection east of the area by early Monday morning. As the aforementioned upper level low moves toward the Central Plains, an upper level trough will linger to the west, across the Desert Southwest and northern Mexico. Uncertainty continues on the exact timing and track of this feature, but any precipitation associated with it looks to remain across are far southeast counties and east of our area. A cold front will move through the region late Monday or early Tuesday. Cooler temperatures are forecast behind the front Tuesday, with highs mainly in the 50s and overnight lows in the 30s. A slow warm up will ensue through the end of the work week. && .PRELIMINARY POINT TEMPS/POPS... Abilene 34 45 42 63 / 50 60 40 80 San Angelo 40 55 52 66 / 50 50 40 80 Junction 51 68 57 67 / 40 40 30 70 Brownwood 41 59 50 65 / 40 40 30 80 Sweetwater 33 44 42 60 / 60 60 50 80 Ozona 48 65 58 65 / 50 40 50 80 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service Topeka KS
518 PM CST Fri Jan 13 2017 ...AVIATION UPDATE... .SHORT TERM...(This evening through Saturday) Issued at 320 PM CST Fri Jan 13 2017 Currently the upper level low pressure is located over the coast of southern CA, while at the surface high pressure was centered over the upper Midwest. Mid level flow out of the southwest has set the stage for an overrunning situation. The challenge in the short term is the chances for freezing drizzle across portions of the area this evening and overnight. The soundings show that saturation is relatively deep over east central KS and there may be periods of lift. There is also a thin layer of drier air near the surface that could potentially limit freezing drizzle from reaching the surface. Also, a few of the models suggest enough lift for isolated to scattered freezing rain showers tonight. The chances for this are low and confined to locations along and south of I-35. If any freezing rain falls tonight the amounts will generally be light, but may cause travel issues. Overnight the surface high pressure will be reinforced over the northern plains and upper Midwest. This will help maintain the northerly to northeast surface winds, which will support the sub freezing air mass in place. A band of freezing rain is forecasted to move over portions of southeast KS tonight and into tomorrow morning. As the upper level low pressure tracks over northern Mexico another surge of moisture will flow northward around the periphery of the sub tropical high over the southeast US. That round of precipitation is forecasted to lift into KS mid day Saturday. Models are still in agreement that surface temperatures will be sub freezing with warm air aloft for northeast KS. Late Saturday into Sunday the ice accumulation is expected to increase across most of the area depending on the actual width of the band of precipitation. Current radar over southwest MO showed that the band of freezing rain today was relatively narrow like 2 to 3 counties wide. If this were to occur then icing would be highly localized. The NAM is suggesting this could be a possibility late Saturday into Sunday, while the GFS and ECMWF are predicting more widespread precipitation. .LONG TERM...(Saturday night through Friday) Issued at 320 PM CST Fri Jan 13 2017 The more significant icing is expected to occur late Saturday into Monday morning. On Sunday models agree that surface temperatures will gradually warm to around or just above freezing. A few degrees will mean the difference between rain and freezing rain. Precipitation rates may also play a role in mixing down those warmer temperatures from above the surface. So you could have transitions of rain vs freezing especially across east central KS depending on the rain intensity. Temperatures are forecasted to be slightly cooler over northern and north central KS so Sunday into Sunday night these areas could receive significant icing. This is when the upper level low pressure lifts out over the plains, which means the warm air advection will increase and will be fighting the sub freezing temperatures. Again, a few degrees will make a huge difference so large potential for lots of ice or not much ice. Cooler warm nose temperatures may also cause sleet to mix with freezing rain. From late Saturday through Monday morning most locations should receive some ice with amounts around one quarter to three quarters of an inch. This will likely cause travel issues and possibly scattered to widespread power outages. Again, there is also the possibility of much lesser ice amounts. Warmer temperatures will definitely move into the area on Monday with highs in the 40s and 50s. Melting will help improve the lasting effects of any ice accumulations, although recovery time is tough to predict and depends on many non meteorological factors. A brief period of mixed precipitation may linger for a few hours over north central into northeastern KS mainly along the hwy 81 and hwy 36 corridor Monday night as the storm system departs the area associated with some wrap around areas of precip. The rest of the period should remain dry and rather uneventful weather wise as much of the Central Plains remains in between a split flow pattern as a broad upper level ridge builds over the region. Temperatures for mid to late week will warm and be quite pleasant and once again well above normal for this time of year into the 50s and 60s by Thursday and Friday. A bit early to tell, but the next upper level weather system may start to encroach on the area by late Friday with the GFS most aggressive on the evolution of upper level features with a closed upper low and negatively tilted trough lifting into the region. Meanwhile, the EC keeps the system further west still over the Southern and Central Rockies. Based on temperature profiles, both models indicate that any precipitation would be all liquid. But, again, this remains too far out in the forecast to have too much degree of confidence. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 518 PM CST Fri Jan 13 2017 RAP and NAM isentropic progs show little if any vertical motion within the stratus this evening. And there are even signs for some weak pressure rises at the surface with possibly some dry air advection near the surface. There may be some -FZDZ through the evening but I don`t know if it will be widespread enough to include a prevailing group for it. So have a Dry forecast with CIGS between 2 and 4 KFT and will monitor radar trends for possible freezing precip. && .TOP WATCHES/WARNINGS/ADVISORIES... Ice Storm Warning from 6 PM Saturday to midnight CST Sunday night for KSZ024. Ice Storm Warning until midnight CST Sunday night for KSZ026- 038>040-054-055. Ice Storm Warning from 6 PM Saturday to noon CST Monday for KSZ008>012-020>023-034. Ice Storm Warning from 6 AM Saturday to midnight CST Sunday night for KSZ035>037. Ice Storm Warning until noon CST Sunday for KSZ056-058-059. && $$ SHORT TERM...Heller/Sanders LONG TERM...Drake/Sanders AVIATION...Wolters
Area Forecast Discussion
National Weather Service Las Vegas NV
600 PM PST Fri Jan 13 2017 .SYNOPSIS...The storm system affecting the area will begin to wind down overnight. The weekend will see drier conditions with ten exception of northwest Arizona where showers may linger into Sunday. && .UPDATE...Widespread rain showers over western San Bernardino will be coming to an end over the next several hours as the upper low west of San Diego drops further south down the west coast of the Baja Peninsula overnight. Some of the higher rainfall amounts in the past 24 hours occurred over southern/western San Bernardino County, as skies clear fog formation possible. Radar is detecting some light showers over Mohave County. HRRR shifts this area northwest into northeast Clark/southeast Lincoln County overnight. Have to keep an eye of Las Vegas as may not be done with the light rain. && .SHORT TERM...Tonight through Saturday Night Primary concern for this forecast period is the current low pressure system that brought all the rain and mountain snow to the area over the last two days. This low continues to push south into Mexico and will eventually push east and toward New Mexico. The dynamics and forcing mechanisms that caused precipitation in our area will go with it. Thus we expect to see a gradual tapering off of rain across the area overnight tonight. Currently the main band of precipitation is beginning to transition over to a NW-SE orientation and weaken. This was anticipated. However, it will take sometime before the rain ends. This is particularly true for areas like Yucca Valley, Barstow area and locations in southern Inyo County. Once we get into Saturday, conditions look good. Skies clear out and precipitation ends. The exception is Mohave County where some lingering showers may affect that area through Sunday. .LONG TERM...Sunday through Friday. A generally dry northerly flow will be over the region Sunday through Tuesday as the upper low over northern Mexico slowly pulls away and is followed by another weak low sliding down the California coast by Sunday evening. North breezes can be expected...especially along the Colorado River Valley Sunday and Monday but speeds do not look particularly strong. It looks like the wet Pacific pattern will bring another round of widespread precipitation to California next week as another atmospheric river is forecast to develop in the base of a broad trough that will move inland Wednesday and Thursday. This will likely bring snow to the southern Sierra by Wednesday afternoon/night and spread a chance of precipitation across the southern Great Basin and Mojave Desert Thursday. There are some differences in the details with the medium range models but they also forecast another fast moving trough and substantial batch of moisture right behind it for Friday. This will lead to chances for precipitation for most of our forecast area Wednesday night through Friday. Little change in temperatures can be expected. && .AVIATION...For McCarran...Showers are generally over for the valley with improving conditions this evening. Sky conditions will be a bit tricky this evening with cigs expected to remain around 6-8 feet, but could rise to around 10-12k feet at times overnight. Cigs will generally remain around 10-12k feet through Saturday. Winds will be north to northeast 6-8 kts through Saturday. For the rest of southern Nevada...northwest Arizona...and southeast California...Scattered showers will mainly impact western San Bernardino and southern Inyo Counties this evening with cigs down to 4-5k feet at times. Vsbys could also lower to around 3-4sm. Conditions will improve later this evening with rising cigs and increased vsbys in those locations. Elsewhere, sct-bkn clouds around 6-8k feet overnight and Saturday. Winds will generally be north to northeast 5-15 kts. && .SPOTTER INFORMATION STATEMENT... Spotter are encouraged to report their snowfall or rainfall amounts to the National Weather Service for this event. && $$ Update...Pierce Short Term: Lericos Long Term: Morgan Aviation: Gorelow For more forecast information...see us on our webpage: or follow us on Facebook and Twitter