Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/28/17

Area Forecast Discussion
National Weather Service Hastings NE
538 PM CST Mon Feb 27 2017 .SHORT TERM...(This evening through Tuesday) Issued at 244 PM CST Mon Feb 27 2017 Focus tonight is on increasing low cloud cover and fog potential in our northern and eastern zones. Flow aloft will transition southwesterly ahead of an upper trough moving into the northern and central Rockies. Southerly low level flow will increase ahead of the approaching system with moisture being drawn north into the Central Plains. An area of low clouds/stratus on the leading edge of the moisture was evident on satellite across central Kansas today. Short term models are consistent with the low clouds lifting north and east overnight with our eastern zones along the edge of the low cloud cover. Models are also in agreement on the potential for visibility restrictions in fog along the stratus across our eastern/northern zones. The HRRR is very aggressive with some low visibilities/dense fog potential several hours tonight and will hit fog potential a little harder in the forecast and HWO. Visibilities improve early Tuesday with the passage of a surface trough and cold front. The cold front moves through right away in the morning with cool air advection more prominent in our northwest zones during the day and have backed off on high temperatures. Models are not in great agreement on whether or not we will see much in the way of precipitation with this system Tuesday/Tuesday evening. Cannot ignore the mid level frontogenesis and lift associated with the shortwave trough moving through Tuesday afternoon and evening and have followed closer to the GFS and ARW and included precipitation chances beginning in our Neb counties and spreading southeast during the day/evening. Precipitation type should be rain for the most part but could see a brief mix of rain/snow and possibly a change to snow before the precipitation ends. .LONG TERM...(Tuesday night through Monday) Issued at 244 PM CST Mon Feb 27 2017 Conditions dry out out overnight Tuesday night behind the departing trough axis. The pattern aloft transitions to a northwest flow regime and at the surface, high pressure builds east of the high plains. Wednesday is shaping up to be a dry, windy day with the potential for critical or near critical fire weather conditions. A tight pressure gradient and deep mixing will result in windy conditions with west/northwest gusts over 30 mph. Have trended dewpoints lower Wednesday afternoon and have roughly the southern third of our cwa with low relative humidity values around 20 percent. Will continue to mention the near critical fire weather potential in the HWO but have held off on headline as confidence is not high enough that low relative humidity will be below 20 percent for three hours. Beyond Wednesday, we are looking for a continuation of dry weather with temperatures trending above normal. Heights rise aloft, then flow turns zonal over the weekend and weekend temperatures are still favorable to reach the 60s. A trough passage and cold front cool things down for Monday. Have kept things dry for now heading into next week as precipitation chances look minimal. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Tuesday evening) Issued at 538 PM CST Mon Feb 27 2017 The main aviation forecast concerns include the chances for low stratus...MVFR ceilings and reduced visibilities due to fog...IFR to MVFR visibilities possible. The latest guidance has kept the worst conditions along and east of KGRI at this time, but have included at least a scattered MVFR deck at KEAR. This will be monitored and amended as confidence is not overly high on how the low stratus/fog may develop/evolve. Additionally overnight there will be a few hours of low level wind shear at both terminals. Winds will be southerly for much of the night before the front moves through changing them to the north- northwest. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Fay LONG TERM...Fay AVIATION...Billings Wright
Area Forecast Discussion
National Weather Service Green Bay WI
521 PM CST Mon Feb 27 2017 Updated aviation portion for 00Z TAF issuance .SHORT TERM...Tonight and Tuesday Issued at 224 PM CST Mon Feb 27 2017 The latest rap analysis and satellite/radar imagery show yesterdays cold front returning northward from the Upper Peninsula to the Dakotas early this afternoon. Winds have turned to the southwest aloft as shortwave energy moves east across the western conus, and are pushing mid and high clouds across the northwest half of Wisconsin. Starting to see light returns showing up over southwest Iowa and northwest Missouri, which is the leading edge of the deeper moisture return. As this moisture lifts northeast into the state late tonight, precipitation timing and potential for snow/freezing rain are the main forecast concerns. Tonight...Southwest winds will increase aloft ahead of the next shortwave trough, and associated cold front that will move southeast across the northern Plains and into the northern Mississippi Valley by daybreak. Ahead of the front, will see a push of deeper moisture accompanied with mid-level fgen which should produce a swath of precipitation over Iowa/Minnesota during the evening before entering Wisconsin overnight. This precipitation is on track to arrive over central and east-central WI between 06-09z, and across northern WI between 09-12z. Though temperatures will not fall much tonight, the combination of readings near freezing over north-central WI and pavement temperatures below freezing will lead to light accumulations of snow/freezing rain from the onset of precip through 8 am, including the morning commute. Will issue a sps to provide a heads up for the north. Elsewhere, precipitation should consist mostly of rain. Lows should fall into the upper 20s over northern WI, to the mid 30s in central WI. Tuesday...The swath of precip will continue to lift to the northeast and exit northeast WI during the morning. Progged soundings indicate that mid-levels temporarily dry out behind this leading swath of precip, but look to remain saturated enough for periods of drizzle to occur thereafter. As the front moves across the eastern half of the state and a wave of low pressure lifts into southern WI during the afternoon, there is potential for more widespread light rain to impact the area. Highs will be warmer than todays readings thanks to the push of warm air, and should range from near 40 in the north to the middle 40s in the south. .LONG TERM...Tuesday Night Through Monday Issued at 224 PM CST Mon Feb 27 2017 Precipitation type for Tuesday night into Wednesday morning continues to be the primary challenge for the long term forecast. Rain is expected to continue across the Fox Valley and central Wisconsin while snow showers and possible freezing drizzle press into northern Wisconsin. A transition to snow in the north is anticipated to be complete by early Wednesday morning, but drying mid levels around midnight may keep freezing drizzle in a little longer as ice crystal introduction into the lower levels diminishes during this time and liquid precipitation freezes to colder road surfaces. The rest of the region will then also change over to snow through the day and into the afternoon with a brief period of slick road conditions possible as road surfaces drop below freezing. Pops will gradually diminish through the day and into the afternoon before the system moves out by the evening. Northwesterly flow, wrap around moisture, and a couple shortwaves aloft will bring in a couple additional chances to see some light snow primarily in northern Wisconsin, but also sporadically through the Fox Valley and central Wisconsin through Thursday. A weak ridge is expected to move into the region Friday morning which will bring in a brief quiet period and colder temperatures overnight. Warm air advection returns ahead of the next shortwave Friday night, for another brief round of possible snow showers ahead of the next ridge that sits in the area for the weekend. Models then show a strengthening surface low pressure system that will enter the region late Sunday night into Monday with another round of possible mixed precipitation as temperatures rise ahead of its arrival, although the timing and placement of this system are still highly uncertain this far out. High temperatures will be around normal through the rest of the work week before advancing warm air advection brings temperatures well into the 40s over the weekend. && .AVIATION...for 00Z TAF Issuance Issued at 521 PM CST Mon Feb 27 2017 VFR conditions to prevail this evening. However an approaching frontal system will begin to lower cigs late tonight, and move precipitation from southwest to northeast across the region. Light snow and/or freezing rain may occur for a few hours over north- central WI late tonight into early Tuesday morning, which could impact flat surfaces such as runways. A period of low level wind shear conditions is also possible late tonight over north-central Wisconsin. LIFR/IFR cigs and poor vsbys are expected to hold tough through much of Tuesday with periods of light rain and drizzle. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......Uhlmann AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Wilmington NC
941 PM EST Mon Feb 27 2017 .SYNOPSIS... A warm front will lift north of the area Tuesday leading to near record high temperatures Wednesday. A strong cold front will bring thunderstorms Wednesday night into Thursday morning, followed by seasonable temperatures late week. Even cooler temperatures are expected by the weekend. && .NEAR TERM /THROUGH TUESDAY/... As of 900 PM Monday...A cluster of thunderstorms have developed off the southern South Carolina coast. Showers and some thunderstorms were more spotty as you move inland across southern South Carolina an southern Georgia. This convection was in association with a warm front. The front is expected to be aligned along the Carolina coast Tue morning and then quickly move N of the area during Tue. The high resolution HRRR model has been accurately portraying convective trends this eve. It shows the thunderstorms passing offshore to our S during the overnight. However, weak isentropic upglide should be enough to produce some showers on the cool side of the boundary. I have increased POPs to the 30-40 percent range. Still do not feel thunder is warranted given the lack of meaningful instability. Where rain does measure, amounts will be a tenth of an inch or less. Dewpoints have been increasing through the day, an indication of the ongoing moistening in the low levels. These higher dewpoints will ensure we will be a good 20 degrees warmer tonight than last night. We are forecasting mainly mid 50s with upper 50s along the immediate coast. The GFS shows sea breeze convection Tue afternoon. Expect a warm day on Tue with highs generally in the middle 70s. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...Active period through mid-week as near record highs give way to a strong cold front and widespread convection Wednesday night. Period begins Tuesday night with high pressure offshore and a warm front well north of the area. Increasing SW winds will drive strong WAA Tuesday night, and mins will likely fall only into the low 60s, mid 60s at the coast. This is more representative of early March highs, and sets the stage for what will be a very warm day on Wednesday. Drying in the mid-levels behind Tuesday`s front will allow sunshine to break through the mid/high level cloudiness which will combine with 850mb temps of 12-14C - near all-time highs for the date according to SPC Sounding Climatology. This suggests highs approaching records Wednesday aftn, with widespread 80+ away from the immediate coast. Forecast for Wednesday, March 1: Wilmington, NC: 81 Record: 83 (1918) Florence, SC: 84 Record: 84 (1997, 1951) N Myrtle Beach, SC: 77 Record: 81 (1955) Wednesday will be very warm, and with deep SW flow, instability will increase as dewpoint values rise into the 60s. This will set the stage for a possible severe weather event Wednesday night as a cold front races across the region. The Storm Prediction Center has our area in a MRGL risk for severe Wednesday night. A strong cold front will be reaching across the area driven by a potent vorticity impulse moving into New England causing height falls locally. Since this front is expected to cross overnight, likely after midnight, instability will be waning, but an HSLC event is possible. While these nocturnal events do not usually create widespread severe, over 50 kts of wind at 1500 ft AGL help to produce bulk shear values over 50 kts, DCAPE of 400-700 J/kg, and 0-1km SRH of 200-300 m2/s2 creates looping hodographs. Additionally, SHERB values reach 0.7 to 0.9 across far NW portions of the CWA, with lower values elsewhere. This supports at least an isolated damaging wind threat even overnight, as well as an isolated tornado threat, but widespread severe is not forecast. However, a weakening squall line will likely move across the area and most places will receive a gusty shower with briefly heavy rainfall. The highest threat for any severe will be west of I-95 Wednesday night. Temps will crash behind the front, but because of the late FROPA, mins will only have time to fall into the mid 50s well inland, around 60 at the coast, still well above normal for the date. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 230 AM Monday...Cold front will be off the coast as the period begins with strong cold advection underway. Showers may linger in the area for the first part of Thu morning, especially along the coast but any activity would be short lived. Canadian high builds in from the northwest Thu into Fri under broad 5h trough aloft. Reinforcing shot of cold air arrives Fri afternoon, along with an increase in northwest winds and a drop in relative humidity. The center of the surface high settles over the area Sat morning, sliding just off the coast into Sun. Pattern aloft transitions from broad troughing to flat flow, which helps push the surface high off the coast Sun. Temperatures near climo Thu and Fri will dip below climo Fri night and Sat. Temperatures will bounce back to climo Sat night as the return flow develops on the backside of the high. Increasing southerly flow Sun combined with westerly flow aloft will push temps several degrees above climo as the period ends. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... As of 00Z...VFR for much of the valid TAF period. However, there is a risk of MVFR ceilings and visibility in showers, mainly between 08z and 15z. A warm front will move across the terminals late tonight and Tue morning. Extended Outlook...VFR. However, there is a risk for reduced ceilings and visibility in showers and thunderstorms, mainly Wed night into Thu morning. && .MARINE... NEAR TERM /THROUGH TUESDAY/... As of 900 PM Monday...A warm front to our S will lift N and into the waters overnight. The front is expected to move N of the waters Tue morning. Given the front will move into the area overnight, wind speeds will decrease slightly, from 10 to 20 kt late this eve to 10 kt or less overnight. While the front is in close proximity, a varied wind direction is likely, but overall, the direction will veer from E and SE ahead of the front to S behind it. Seas will be 2 to 3 ft. SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...Cold front will cross the waters late Wednesday night, with SCA conditions possible. Ahead of this boundary, SW winds will increase steadily from 10-15 kts early Tuesday night, to 15-25 kts during Wednesday immediately ahead of FROPA. The frontal passage will be accompanied by a sudden wind shift to the NW with only slow decreasing speeds through the end of the period. Seas of 4-7 ft are expected late Wednesday and Wednesday night, rising from 3-4 ft Tuesday night, and a 5-6 sec southerly wind chop will be the primary wave group. A subtle decrease in amplitude is possible very late Wednesday night as the winds begin to shift offshore. Additionally, sea fog will be possible Tuesday night and especially on Wednesday as high moisture air advects across cooler shelf waters. Have not introduced any sea fog into the forecast attm as there is some concern that Td-T spreads may be slightly too high, and parcel residence times may not be long enough for saturation due to the fast wind speeds. Will mention the possibility here and address in the official forecast as we get closer to the time of potential sea fog. LONG TERM /THURSDAY THROUGH FRIDAY/... As of 230 AM Monday...Strong cold front will be either moving across the waters or just east of the waters as the period begins. Offshore flow will drop from a solid 15 kt in the morning to 10 to 15 kt in the afternoon. Weak offshore flow continues Thu night into Fri before another surge of cold air pushes across the waters Fri afternoon/evening. This surge will push northwest flow to 15 to 20 kt with gusts approaching 25 kt. Seas will trend down, from 3 to 6 ft Thu morning to 1 to 3 ft Fri morning, as offshore flow decreases. Increasing winds later Fri and Fri night will result in a slight bump in seas with dominant wave becoming a short period wind wave. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ NEAR TERM...RJD SHORT TERM...JDW LONG TERM...III AVIATION...RJD
Area Forecast Discussion
National Weather Service Jackson MS
958 PM CST Mon Feb 27 2017 ...ACTIVE WEATHER EXPECTED THROUGH MID WEEK... .DISCUSSION... Adjustments where made to the night time temperatures to reflect what is currently being observed. At the moment night radiation cooling is winning over the warm advection. However in a few hours the winds will start to pick up and temperatures will rise steadily--by sunrise the region will be in the balmy mid to upper 60s. In the southeastern region of the CWA, patchy fog was added into the forecast in the early morning hours. The HRRR was showing visibility of less than a quarter of mile south of I-20 and east of I-59. If a dense fog advisory would to be issued overnight, it would be likely to be for this immediate area. /12/ && .AVIATION... 00Z TAF discussion: Very moist air will bring more LIFR/IFR ceilings overnight with some potential for LIFR fog, but winds may be a bit too strong getting much fog. Expect good mixing of the boundary layer Tuesday resulting in improved ceilings/visibility by early afternoon along with gusty southerly surface winds. Going into Tuesday night, we will see plenty of stratus redevelop in the persistent southerly flow pattern ahead of the next cold front scheduled to push through Wednesday. /EC/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 62 82 66 77 / 17 12 23 64 Meridian 59 82 65 77 / 17 13 18 61 Vicksburg 63 84 68 76 / 14 15 25 63 Hattiesburg 59 83 66 81 / 43 12 14 46 Natchez 64 83 67 77 / 27 10 18 59 Greenville 59 80 66 72 / 54 42 41 57 Greenwood 58 81 67 74 / 48 42 36 68 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ 12
Area Forecast Discussion
National Weather Service New Orleans LA
738 PM CST Mon Feb 27 2017 ...SOUNDING DISCUSSION... The sounding this evening depicts the unstable environment storms across the northern part of the area and near the Mississippi Gulf Coast were working with earlier today. Mixed layer CAPE is at 1500 J/KG, though without forcing current thinking is still that tonight remains nearly dry. There is 42 kts of sfc to 6 km shear with winds southerly at the sfc and becoming west with height. Peak wind is 110 kts at 230 mb. PW is well above average at 1.5 inches. Krautmann && .PREV DISCUSSION... /issued 352 PM CST Mon Feb 27 2017/ SHORT TERM... For today the HRRR handled the area well...but coverage and strength was more aggressive than what took place today. Fairly strong helicity evident as some of the storms were rotating today. Convection associated with the upper jet expected to diminish through the evening as the upper support pulls off to the north and east. General thunder only expected in the far SW corner of MS for our area tomorrow. Warm and dry for Mardi Gras. In fact, it could be close to the warmest Mardi Gras on record which is currently 83 degrees. LONG TERM... A strong cold from is poised to enter the area Wednesday associated with With the front comes a Marginal Risk of severe weather east and west of a line across Lake Pontchartrain east to the MS Gulf Coast. The Slight Risk touches our counties in SW MS. Most of the energy will remain further north, however the tail end of a squall line could produce gusty winds, small hail, and an isolated tornado. ECMWF 0-2km lapse rates steepest around 18z over the area with model helicity of 200 ms/ss mainly in SW MS south to KBTR. Forecast sounding CAPE values decrease as the front travels south from 1120 j/kg around Monroe at 06Z Wed to 490 j/kg at KMSY at 00Z Thu. The area of thunderstorms are expected to weaken as the systems moves south. Cold but dry conditions following the front for the remainder of the week. Return flow begins in south Texas Saturday with rain chances increasing again late in the weekend to early next week. AVIATION... VFR conditions expected until some localized fog and lower ceilings Tuesday morning. BKN clouds will continue overnight with OVC 1000-1500ft possible for a few hours Tuesday morning. Winds will remain easterly without impacts to terminals. MARINE... The upper trough will continue to move east keeping winds mainly 10-15 knots. Bigger impact will be a cold front Wednesday with winds increasing to over 20 knots in the offshore waters. Most likely a Small Craft Advisory will be needed following the cold front for the strong northerly flow. Some thunderstorms can be expected as well associated with and ahead of the cold front. DECISION SUPPORT... DSS code: Blue. Deployed: NOLA EOC. Activation: None. Activities: Support for City of New Orleans through Tuesday. Monitoring convective trends. Decision Support Services (DSS) Code Legend Green = No weather impacts that require action. Blue = Long-fused watch, warning, or advisory in effect or high visibility event. Yellow = Heightened impacts with short-fused watch, warning or advisory issuances; radar support. Orange = High Impacts; Slight to Moderate risk severe; nearby tropical events; HazMat or other large episodes. Red = Full engagement for Moderate risk of severe and/or direct tropical threats; Events of National Significance. && .PRELIMINARY POINT TEMPS/POPS... MCB 66 84 66 79 / 20 10 20 50 BTR 68 83 68 81 / 20 10 10 50 ASD 67 83 66 82 / 20 10 10 40 MSY 68 81 68 82 / 30 10 10 30 GPT 67 77 66 78 / 20 10 20 30 PQL 65 79 65 79 / 20 10 10 30 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$
Area Forecast Discussion
National Weather Service Pocatello ID
158 PM MST Mon Feb 27 2017 .SHORT TERM...Tonight through Thursday. Upper trough axis and attending snowfall currently working through the region and should clear the ERN border this evening. Thus have extended the Advisory to 8pm per the HRRR model progs. Secondary storm system follows late tonight/Tuesday with another round of light snowfall and strong afternoon winds within the Snake River Plain. Thus the wind advisory remains of track for Tuesday afternoon. A moderately strong and moist NW flow will remain over the region Tuesday night through Thursday resulting in light ongoing snowfall across the CNTRL and NE mountains in upslope NW flow and slowly warming temperatures. Huston .LONG TERM...Thursday night through Monday. Will see a continued warm up Friday with temperatures getting back close to seasonal normals with any showers mainly limited to the central mountains and Upper Snake River Highlands along the Wyoming and Montana borders. By Saturday high temperatures should be up into the low 40s to around 50 in the Snake Plain and eastern Magic Valley ahead of a cold front. Temperatures should remain above freezing Saturday night with snow melt flooding again becoming a concern. GFS and European differ in timing of cold frontal passage Sunday with European much quicker early Sunday and GFS not driving it through until late Sunday night. Have high temperatures dropping back to below seasonal normal Sunday and Monday. GK && .AVIATION...Band of snow worked through the region with brief IFR conditions at SUN, BYI and PIH and at 1 pm at IDA. Expect IDA to improve rapidly this afternoon once band exits. SUN, BYI and PIH have returned to VFR or MVFR conditions. Expect some MVFR to IFR conditions at DIJ this evening as this band moves through. Expect BYI, SUN and PIH to be mainly VFR with possible MVFR ceilings at IDA and DIJ overnight. 10 to 20 knot winds expected at BYI, PIH and IDA. Expect windy conditions by Tuesday afternoon with 20 to 30 knot sustained at those 3 sites. Snow showers again a possibility Tuesday especially at SUN and DIJ with MVFR to IFR ceilings expected. GK && .HYDROLOGY...Cooler temperatures have helped to mitigate snow melt issues. The next warm up comes late this week peaking on Saturday with snow melt follow-through expected into Sunday. Huston && .PIH WATCHES/WARNINGS/ADVISORIES... Wind Advisory from noon to 6 PM MST Tuesday for IDZ020-021. Winter Weather Advisory until 8 PM MST this evening for IDZ019-023- 025. && $$
Area Forecast Discussion
National Weather Service Raleigh NC
858 PM EST Mon Feb 27 2017 .SYNOPSIS... High pressure will push further offshore through this evening, followed by a warm front lifting through the area tonight. A mild flow from the southwest will persist Tuesday through Wednesday, ahead of a cold front that will cross the area Wednesday night. && .NEAR TERM /THROUGH TONIGHT/... As of 900 PM Monday... The 00z GSO sounding hints at a key shift in the forecast this evening and that is extremely dry conditions below 700 mb all the way to the surface. As a result, not much moistening of the atmosphere has occurred and even though isentropic lift will pick up during the overnight hours, having a hard time believing that we will get any precipitation west of US Highway 1. Currently the warm front can be seen in the observations near Columbia SC with an increase in dewpoints of around 10 degrees. Earlier runs of the NAM, WRF and others depicted precipitation forming in the western Piedmont and moving east during the early morning hours as this front pushes northward. Instead, would now favor the HRRR and RAP solutions which show precipitation mainly in the southeastern counties and after 6z and continuing to into the morning with the bulk of the precipitation occurring east of I-95. Expect low temps in the mid 40s in the Triad to low 50s in the southeast. && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... As of 320 PM Monday... Tuesday...the isentropic lift will decrease shortly after daybreak Tuesday which should lead to a diminishing of the shower coverage. After 14z, the greatest threat for a shower or two will be roughly along and east of I-95. An increasingly moist and conditionally unstable air mass coupled with the approach of a perturbation lifting east-ne from the TN Valley into the mid-Atlantic Tuesday afternoon will trigger a few additional showers and possibly a thunderstorm. SInce forcing fairly weak, do not expect coverage to be any worse than isolated or scattered. A steady sly flow along with periods of sun should boost afternoon temperatures into the low-mid 70s with upper 70s highly probable across the far southeast. Tuesday night...the mild weather will continue as a low level jet will strengthen overhead in response to an amplifying s/w lifting to our northwest. The variably cloudy skies and steady sly flow will maintain overnight temperatures in the 60-65 degree range, closer to normal daytime highs for early-mid March. While a shower or two may occur to the north-nw of Raleigh and the Triad, the bulk of central NC will remain dry as forcing expected to be weak at best. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... As of 235 PM Monday... Wednesday and Wednesday night: As the low pressure system over the Midwest moves eastward on Wednesday, the parent low will move over the Great Lakes region while the upper level trough/sfc cold front extending from the Great Lakes southwest through the ARKLATEX progress east toward the Carolinas. Over Central NC, continued warm southerly flow will persist through the day Wednesday as cloud cover and chances for convection increase from the west. Highs will range from mid 70s NW to low 80s south. South-southwesterly winds will be quite strong on Wednesday, sustained 15-20 kts with gusts to around 30 kts, strongest just before sunset and then again with the front. Latest model solutions continue to suggest the best chances for convection (shower and possible strong thunderstorms) will move into the west late Wednesday evening, quickly moving eastward through Central NC by early Thursday morning. Despite the poor diurnal timing of the axis of convection the high (uni-directional) shear and low (500-1000 J/Kg) CAPE will result in the slight chance for thunderstorms to produce some damaging winds as they move through the region. The likelihood decreases with time as the showers progress through the area. Wednesday night, winds will become more northwesterly, cold air advection will commence and skies will begin to clear. As a result of current fropa timing, low temperatures will range from mid 40s NW to mid 50s SE. Winds will continue to be breezy overnight (10-15 kts with gusts to around 20 kts). Thursday through Monday: This period is expected to remain dry. Highs Thursday and Friday will still be in the upper 50s to mid 60s, lows Thursday night in the mid 30s. A reinforcing dry cold front will push through late in the week with the coldest temperatures (mid 20s to around 30 degrees) expected Friday night/Saturday morning as the surface high moves overhead. Highs Saturday will be the lowest of the period, mid to upper 50s. Expect moderating temperatures once again for the remainder of the weekend and into next week as yet another low pressure system develops out west and the flow over the Carolinas becomes increasingly southerly. && .AVIATION /00Z Tuesday through Saturday/... As of 710 PM Monday... VFR conditions are likely to hold for a few more hours, but a trend toward IFR at INT/GSO and MVFR elsewhere is expected later tonight, mainly after 08z. Mid and high cloudiness over the area, caused by a weak mid level disturbance, will be exiting slowly to the east through tonight, however lower level moisture will stream in from the SW later tonight, generating a trend to IFR cigs at INT/GSO and MVFR cigs at RDU/FAY/RWI after 08z, lasting through around 13z, at which time cigs will rise to MVFR at INT/GSO and VFR elsewhere through mid/late morning. Winds will increase during the morning from the SW at 8-12 kts with occasional gusts to 15-20 kts, lasting through the afternoon. A few showers and isolated storms are possible late Tue afternoon into the evening, but coverage and confidence are too low to mention at this time. Looking beyond 00z Wed, a trend back down to sub-VFR cigs is expected after 06z early Wed morning with a steady breeze from the SW overnight. Low level wind shear (unidirectional) is possible late Tue night through daybreak Wed. Cigs will lift slowly toward VFR through Wed, with a good chance of showers and storms -- some of which could be very strong -- very late in the afternoon through the evening and nighttime hours, ahead of a cold front. Strong and gusty winds from the SW are likely Wed into Wed night, sustained around 20- 25 kts with gusts of 30-40 kts possible. Cold front passage Wed night will shift winds around to NW with clearing skies, and VFR conditions will dominate Thu through Sat. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...GIH NEAR TERM...Ellis SHORT TERM...WSS LONG TERM...KC AVIATION...Hartfield
Area Forecast Discussion...UPDATED
National Weather Service Springfield MO
854 PM CST Mon Feb 27 2017 .UPDATE... Issued at 838 PM CST Mon Feb 27 2017 Forecast remains largely on track for this evening. 00Z KSGF sounding showed about 139j/kg of MU cape however there is a substantial cap around 650mb. 00Z Norman sounding showed an impressive mid level dry layer and inversion with about 2000MU cape above. This airmass was streaming towards the area and therefore casts some questions as to how widespread precip will be tonight. While a few scattered showers have developed around the SGF metro as of this writing, expect that for the most part coverage wont be particularly widespread. HRRR and other models are generally in agreement that locations east of US Highway 65 and especially areas across south central Missouri have the best chance of seeing a shower/storm tonight. As far as severe potential, there is enough instability and shear combo to warrant a limited threat of an isolated large hail to quarter size however thinking this would be limited to areas across far south central Missouri. Stratus will continue to spread north into the area ahead of an approaching warm front. We have inserted some patchy fog overnight especially in south central missouri. CLoud cover will keep temps mild overnight especially from Springfield west with readings remaining near 60 overnight. Lastly, forecast model data will continue to be looked at overnight for the severe potential on Tuesday. Quick glance at data from the 00z NAM shows a majority of the day Tuesday dry with storm chances increasing after dark Tuesday evening. Stay tuned. && .SHORT TERM...(This afternoon through Tuesday) Issued at 1048 AM CST Mon Feb 27 2017 Southeast winds will help temperatures this afternoon climb into lower to middle 60s for most of the Ozarks. An area of showers and a few storms were moving to the northeast out of Oklahoma in an area of isentropic lift and generally with the surface to mid level flow. A few storms are expected to move across the region this afternoon, however, a fairly strong cap should keep any convection in check. With MUCAPE values this afternoon from 150 to 500 j/kg some areas across extreme southwestern Missouri may hear some thunder but it will be the exception rather than the rule. The surface winds will shift from the southeast to the southwest through this evening and overnight. Showers and a few rumbles of thunder will continue but coverage should be scattered in nature. Enough instability may develop late this evening into tonight for a penny to quarter size hail risk with a few of the strongest storms across south central MO. The continued southerly flow and shift to southwesterly flow at the surface will aid in bringing low and mid level moisture into the region by Tuesday morning. The southwesterly flow at the surface and aloft will maximize by overnight and through Tuesday morning as surface low pressure moves across the plains and moves a cold front towards the region. Models have been in good agreement with the exception of the NAM, in developing modest instability across the region with CAPE values by Tuesday afternoon in the 900-1600 j/kg range. In addition, shear will be very strong with 60-80kts showing up during the afternoon focused along and south of I-44. Models have continued to show a CAP, but it becomes pretty weak during the afternoon after/around 21z with less than 10j/kg of CINH noted across the Ozarks. This works in favor of the development of strong to severe storms during the afternoon. One concern would be the very strong shear, overcoming the modest instability and shearing the tops off of the storms as they develop. While this may occur, the concern remains that strong winds and even a tornado may be possible with storms that can develop and take advantage of the instability and shear. The cold front will make its push through the region Tuesday evening. Storms will remain along the front as it makes its way eastward, though the CAP looks to strengthen a bit as the front moves through. The frontal forcing will most likely be capable of overcoming the increasing CINH, but instability will be on the wane as well. .LONG TERM...(Tuesday night through Sunday) Issued at 1048 AM CST Mon Feb 27 2017 The cold front will move through the region Tuesday night and be well west of the Ozarks by sunrise Wednesday morning. A few lingering post frontal showers may be exiting the southeastern Ozarks after sun up, but will quickly move east of the region. High pressure will filter into the area through the day Wednesday with temperatures only climbing into the 50s during the afternoon. With several additional rounds of high pressure expected through the end of the week and into the weekend, the region will remain dry with temperatures climbing back into the 60s to near 70 by the weekend. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 527 PM CST Mon Feb 27 2017 A gradual lowering of ceilings will occur Tonight as moisture increases from the south. MVFR ceilings are likely at BBG by mid to late evening and then SGF and JLN after 03z. Still some question as to exact timing of the stratus. A brief period of IFR is even possible. Surface winds will remain gusty out of the south tonight with some low level wind shear possible at BBG overnight. A few showers and storms will likely come close to the BBG airport late tonight and have put in VCTS for now. Confidence is low however there is some patchy fog potential at JLN by morning. A brief increase in ceilings may occur during the day Tuesday before more showers and storms arrive. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ UPDATE...Burchfield SHORT TERM...Hatch LONG TERM...Hatch AVIATION...Burchfield
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Tuesday) Issued at 310 PM CST Mon Feb 27 2017 Recent water vapor imagery and RAP analysis showing upper flow becoming more southwest ahead of a shortwave moving into California. Another upper wave was moving east across southern Canada. Surface pressures were falling quickly over central Kansas with warmer air surging north. Deeper moisture with this warmer air keeping skies partly sunny, with enough depth of the moisture for a few showers to form in eastern areas. Several items of interest in tonight into Tuesday afternoon. May see a few showers into the early evening in the east where isentropic upglide remains, with weak instability keeping a thunder mention going. Southerly winds will persist overnight and attempt to saturate a shallow layer near the surface. Some models are squeezing out some drizzle, but given the shallow moisture depth and little vertical motion, have not included it. With the aid of the northern wave, initial surface low moves across southern Nebraska tonight with next low moving across northern Kansas during the day. Cold air advection slowly works in, but should have enough clearing of the low cloud for a warmer day for most locations ahead of a cold front. Have increased temps most areas with this in mind but confidence in high temps is not high. Mixed- layer CAPE increases to at least a few hundred J/kg in east central Kansas. Wind fields will be quite strong and could support a some updrafts capable of producing small hail. To the northwest, frontogenesis aloft will bring at least a small chance for rain to develop late in the afternoon. .LONG TERM...(Tuesday night through Monday) Issued at 310 PM CST Mon Feb 27 2017 The bulk of the interesting weather will be in the first 9-12 hours of the period on Tuesday night/early Wednesday morning. A modest meridional shortwave trough axis will be centered along the High Plains at 00Z Wed with a 140 kt jet steak rounding the base of the trough and lifting northeast. Increasing 925-700mb frontogenetical forcing, modest ageostrophic ascent in the left- front region of the jet, and a combination of slantwise/upright instability will set the stage for a narrow band of precipitation bisecting the CWA. The major questions revolve around the location of the banded precip and attendant BL thermodynamic properties. The 12Z GFS was a northern outlier in the placement of the band in comparison to the NAM/ECMWF/SREF/NMM/ARW, so leaned towards the southern solution of the placement of the precip. The thermodynamic setup was a bit trickier to resolve. Sounding profiles in the mid levels depict a classic heavy snow setup with omega maximized through the center of the DGZ. MUCAPE values above the Fg zone will range from 100-200 J/kg, more than ample to enhance precip rates during the 3-6 hour period. To account for the intense snowfall rates and mesoscale nature of the band, adjusted the Tuesday night forecast as follows: 1) Raised snow ratios to a mixture of the NAM/GFS, substantially higher than SuperBlend. 2) Raised the rain/snow thresholds in the ForecastBuilder to 36/40, 2 to 3 degrees higher than the default. 3) Adjusted hourly temperatures down to near the wet bulb shortly after the onset of precip. Even with all these tweaks, surface Tw values of +2 to +4 C may still be too much to overcome to generate any meaningful snowfall amounts. The updated forecast snowfall amounts only tops out at 0.5" near Manhattan, but even a couple degree difference in the wet bulb could result in several inches of snow along a very narrow corridor. The strength of the ongoing CAA and whether or not the precip can modulate the BL fast enough will play a key role in precipitation type and snowfall accumulations. Stay tuned for further updates! Strong longwave ridging will build over the western CONUS after this system pushes out by 12Z Wednesday. The result will be steadily warming temperatures and mostly clear skies for the latter half of the work week and the weekend with the next wave of any consequence not arriving till early next week. H850 temps will rebound to 0 C Thursday, +5 C Friday, +9 C Saturday, and then +14 C Sunday. Thus, look for the return of well above average temps in the 60s and 70s by this weekend. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 545 PM CST Mon Feb 27 2017 Potential for LLWS as the LLJ kicks in from 03Z-10Z time frame. This is more of speed shear change near the 2kft level as opposed to directional change. Lower confidence in arrival of stratus deck, so have delayed that also and have not had the confidence to go below MVFR conditions once it does build in. This will be something that will have to monitored more closely. Good confidence in SSW winds through the period as the system to the west becomes more organized and eventually lifts through the area. Could see some gusts near the midday time frame before a wind shift late in the period. Thinking precip chances remain low. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...65 LONG TERM...Skow AVIATION...Drake