998 FXUS64 KFWD 091758 AAA AFDFWD Area Forecast Discussion...UPDATED National Weather Service Fort Worth TX 1258 PM CDT Tue Oct 9 2018 .AVIATION... /18Z TAFS/ Challenges: All near-term issues with convection(not continuous), cigs, and vsbys through 21z, then then timing wind shifts 00z through 09z Wednesday with a pre-frontal trough arriving by mid evening, then cold FROPA arriving by midnight or shortly thereafter. Cigs/vsbys will continue to fluctuate between MVFR cigs on either side of FL020 and VFR cigs BLO FL100 through 21z and in behind the line of heavier TS/SHRA currently moving across all North and Central TX airports. Afterward, VCSH/-RA could linger through 00z before veering low level winds from the W/SW flow around 10 knots occurs in wake of our linear storm cluster. Cold FROPA is progged to arrive across DFW Metro airports between 04z-06z, then through Waco Regional by 06z with winds shifting NW 10-15 knots with possible higher gusts. For now, confidence is too low to add gusts. Otherwise, skies will scatter after FROPA and by 09z Wednesday. DFW will be right on the western edge of nocturnal TS/SHRA development from the parent mid-level upper trough moving across the region. At this time, most activity should be "elevated" in nature and with weak mid level lapse rates less than 6 deg C/km, will only advertise VCSH/-RA for a few brief hours either side of 06z Wednesday. 05/ && .MESOSCALE UPDATE... /Issued 1058 AM CDT Tue Oct 9 2018/ Main concern through today will be the potential for severe weather across North and Central Texas. The RAP analysis continues to favor a concentrated area for increased tornado potential through the early afternoon hours for Central Texas. Clearing skies will lead to an increase in instability, priming the atmosphere for additional storm development as we go into the afternoon. Low level wind shear is becoming enhanced given the localized southeasterly to easterly winds. Within the large scale southeasterly flow, a few radar echoes are now moving into East Texas, likely from a slight perturbation in the pressure field. Showers will have the potential to intensify into supercells given 2500+ J/Kg forecast CAPE, and with the enhancement of the surface winds, storms that do develop will have the potential to rotate increasing the threat for a few tornadoes. Across North Texas (including the Metroplex), the threat for severe weather has ended as much cooler temperatures are expected to remain due to the extensive cloud cover from the convection across Central Texas. Previous thinking that another round of storms would move in from the west is fading, and now believe only a few showers will remain across North Texas as the atmosphere continues to be worked over. Hernandez && .SHORT TERM... /Issued 338 AM CDT Tue Oct 9 2018/ /Today and Tonight/ The upper level trough is starting to swing more towards a negative tilt tonight with widespread showers and storms continuing across mainly the western half of the state. By daybreak, we expect this activity will already be in our western counties with isolated to scattered rain activity occurring east of this area. Instability has been increasing across our southwestern zones as the low level jet increases in that area, and we anticipate some of this increased instability will continue to spread north during the early morning hours. So as these storms move into our western areas, a severe weather threat will exist, in particular in areas that are not disturbed by outflow boundaries. Model guidance tonight continues to suffer with the smaller scale trends and timing of convective evolution today, but there is an overall agreement that the morning complex of storms will push farther east across the region than previously thought, and a second round of storms will develop later in the day/evening. Severe storms will be possible along and ahead of the leading edge of the morning complex as instability continues to increase through the morning hours. Instability will be greatest along and south of I-20 and this may be where the higher threat for severe storms will be. We will carefully be analyzing mesoscale properties and radar trends to anticipate where the greatest threat for severe storms will be located. As the complex of storms continues east in the afternoon hours, the severe weather threat may also continue, but a weakening of the line is expected as the low-level jet weakens and the complex moves further away from the upper level trough. However, this will not be the end of the rain as most models indicate another round of convection will develop sometime in the late afternoon and early evening hours. This second round may form along the front as it starts to enter our region. The atmosphere may be too worked over by this time to support an additional threat for severe storms, but the threat cannot be completely discounted at this time and will depend on how far east and how extensive the morning complex of rain tracks. It's possible the threat this evening could be limited to our eastern counties. The final round of storms is expected to move pretty swiftly east with the front and exit the region late tonight. The main severe weather hazard will be damaging winds. Although some hail cannot be discounted, its threat may be limited by weak lapse rates and a deeply moist atmosphere. Unfortunately a tornado threat cannot be discounted either as nicely veering winds in the lower levels of the atmosphere will be maintained and has already resulted in some Tornado Warnings in West Texas. Storms today will be efficient rainfall producers which would result in a flash flooding threat if any storms stall, train or are slow- moving. With deep southerly flow through the atmosphere this morning, the flood threat may be slightly higher in the morning hours as the complex slowly moves across the region. However, we do not plan to issue a Flood Watch due to uncertainties in the speed and maintenance of the morning complex. As the front sweep across the region this evening and tonight, much welcomed cooler and drier air will filter into the region. JLDunn && .LONG TERM... /Issued 338 AM CDT Tue Oct 9 2018/ /Wednesday through Tuesday/ Much of the region will start Wednesday in the 50s, and possibly even the upper 40s in a few spots in our northwestern counties. This could be the coolest temperatures the region has seen since last Spring. Very pleasant weather with below normal temperatures, sunny skies and low humidity will prevail Wednesday and Thursday. During this time we will remain under west-southwest flow aloft as Hurricane Sergio heads east for Baja and Mexico and the next upper level trough digs along the West Coast. On Friday, Sergio will make landfall on Baja and Sonora, Mexico. Increased cloud cover and light rain will spread across much of North and Central Texas as mid level moisture surges ahead of Sergio and weak energy starts translating east from the storm. The rain will be falling from the mid levels of the atmosphere and will likely spend a good portion of the day fighting drier air below the cloud deck. The best rain chances will be mainly north of I-20 and west of I-35. The remnants of Sergio are forecast to maintain identity across Mexico and enter West Texas Saturday morning. Both the GFS and ECMWF have a defined surface low that moves northeast across our northwest counties late Saturday. Our surface winds also finally turn to the southeast, increase in speed and quickly draw some Gulf moisture into the region. At this same time, the upper level trough from the West Coast is continuing to inch closer to the region and is assisting a strong cold front moving down the Plains. Rain chances increase Saturday through Sunday, but the GFS and ECMWF differ in how this rain unfolds. The GFS has more rain with the low pressure system on Saturday and Saturday night, while the ECMWF has more rain with the cold front on Sunday. The details on the best timing and any possible threats with this next system will be refined this week. The weekend cold front will allow the coolest air of the season to filter into the region. Highs in the 60s are expected for the early part of next week with overnight lows in the 40s and 50s. JLDunn && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 75 57 75 56 72 / 100 70 0 0 0 Waco 80 59 78 57 76 / 90 60 0 0 0 Paris 80 60 74 54 71 / 90 90 10 0 0 Denton 73 54 73 54 71 / 100 70 0 0 0 McKinney 76 57 73 53 70 / 100 80 5 0 0 Dallas 77 59 76 56 72 / 100 70 0 0 0 Terrell 80 60 77 56 75 / 80 80 5 0 0 Corsicana 80 62 78 56 73 / 80 80 5 0 0 Temple 83 60 78 57 76 / 90 60 0 0 0 Mineral Wells 72 53 74 52 72 / 100 30 0 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 05/08