DFW FORECAST DISCUSSION
000 FXUS64 KFWD 160436 AFDFWD Area Forecast Discussion National Weather Service Fort Worth TX 1136 PM CDT Sat Jun 15 2019 .AVIATION... Timing thunderstorms will continue to be the primary challenge with this TAF package. A complex of storms is finally starting to organize across the Big Country at 04Z. These storms will continue to move east through the night, reaching the Metroplex TAF sites around 09Z. Waco may see a few storms in the vicinity a few hours after sunrise, but most activity should remain to the north. Storms should exit to the east shortly after sunrise Sunday with the passing of a shortwave trough. Much of Sunday should be storm free, however, a second round of storms will likely develop early Sunday evening when another shortwave and a cold front enter the region. A 40 knot low level jet will bring stratus northward overnight with MVFR ceilings expected in Waco around 09Z and slightly later across the Metroplex TAF sites. However, thunderstorms could briefly alter ceiling trends. VFR conditions are expected Sunday afternoon and evening. A breezy south wind will continue between 12 and 16 knots along with some gusts to 26 knots. The wind gusts in and around thunderstorms will likely be a bit stronger. 79 && .SHORT TERM... /Issued 328 PM CDT Sat Jun 15 2019/ /Tonight through Sunday/ This afternoon`s satellite imagery reveals a shortwave trough over New Mexico moving east towards the Texas Panhandle. Thunderstorms should develop quickly this afternoon across west-central Texas in the vicinity of a dryline as forcing associated with the shortwave arrives. Scattered storms will spread east along with the disturbance, eventually congealing into an MCS while approaching North Texas this evening. The latest timing brings activity into the northwest zones around 10 PM, then into the I-35 corridor (mainly along and north of I-20) around midnight. There is a possibility of storms weakening the farther east they travel, but with good instability in place and continued lift from the shortwave, a damaging wind threat will likely exist late into the night. Storms will spread east of I-35 overnight and will have begun to spread south of I-20 where a warm, moist tropical airmass will exist. Activity will continue propagating southeast before exiting the area Sunday morning. Additional thunderstorms are likely later in the day Sunday, though the timing is a lot less certain. Several models are keying in on redevelopment shortly after sunrise somewhere along the Red River associated with a secondary vort max swinging around the back edge of the main shortwave. If so, activity would propagate southeast across the region during the morning, exiting to the southeast early Sunday afternoon. It is possible, however, that conditions will have become too stable for morning development following the overnight convection. In this case, despite the forcing associated with the secondary impulse, we would need to wait for several hours of surface heating and destabilization, and additional storms would hold off until afternoon (and would be more isolated in nature). Either way, more showers and storms may already be developing just northwest of the area by late afternoon as the next disturbance approaches from the west, continuing what is likely to be several days of unsettled weather. 30 && .LONG TERM... /Issued 328 PM CDT Sat Jun 15 2019/ /Sunday Night Onward/ Active weather should persist Sunday night and into Monday, with a continued risk for occasional strong or severe storms lasting into the week. This type of activity cannot be easily "timed" or "placed" as it is driven by small-scale features dependent on preceding convection, so the main message here is to keep an eye on weather if you have outdoor plans and be prepared for perhaps rapidly changing forecasts in the coming days. Through the extended, the environment will remain characterized by strong to extreme instability owing to ample low-level moisture content and warm daytime temperatures coupled with incredibly steep mid-level lapse rates. As is typical heading into the summer months, westerly flow aloft and attendant deep-layer shear will remain rather weak, occasionally strengthened by low- amplitude shortwave disturbances. This high CAPE low shear environment will be the story of the extended forecast, contributing to periodic thunderstorm chances over the next several days. At the beginning of the extended period Sunday evening, convection may already be ongoing across portions of the forecast area as previously discussed. Despite some convective overturning and stabilization from storms earlier in the day, a quick recovery with persistent south flow should allow for new development to occur, likely northwest of the CWA late Sunday afternoon and evening. This activity would likely form into a complex or two which should dive southeastward into North Texas later Sunday evening and overnight. A strong/severe storm risk in the form of wind/hail will accompany this activity simply due to the nature of the instability present. The weak shear may limit individual storm intensity/longevity while favoring primarily a multicellular storm mode. There will also be a continued risk for flash flooding, as some areas will likely have received multiple rounds of rainfall through Sunday night. All of these storms should continue to shift southeastward through Monday morning. After perhaps a bit of a lull during the first part of Monday, renewed development is expected throughout the day. Several mesoscale boundaries should exist from previous convection, along with perhaps a reinforced effective frontal zone that may be driven southward into North Texas from Oklahoma. This will set the stage for widely scattered convection occurring, especially during the peak heating hours Monday afternoon and through Monday evening. The Tuesday/Wednesday time period should see slightly lower convective chances with an attendant warm-up due to less storm/cloud coverage during the afternoon hours. Storms will likely be confined to typical summertime diurnally-driven convection in the afternoon and evening hours each day. Coverage should be more limited due to the presence of some weak upper ridging and slow height rises. Isolated storms will still pose a marginal severe risk for hail and downburst winds with strong instability remaining in place. Heat index values will be in the upper 90s to near 100 on Tuesday, but may creep into the 100-105 range on Wednesday depending on the amount of cloud cover or afternoon convection. Meanwhile, coarser guidance has been rather persistent regarding the potential for a thunderstorm complex to develop across the TX Panhandle and western Oklahoma on Wednesday night which would have a tendency to dive southeastward into North Texas within increasingly northwesterly flow aloft. Despite what will likely be a smaller-scale process, model run-to-run consistency lends credence to this possibility, and PoPs have been configured as such for the time being. The warm and humid conditions will prevail through the end of the week with continued convective chances primarily during the peak heating hours each day. Highs will remain in the mid to upper 90s with heat index values in the neighborhood of 100F. -Stalley && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 73 88 72 88 72 / 50 30 60 50 40 Waco 75 91 73 90 73 / 40 30 60 50 20 Paris 72 85 69 81 69 / 50 40 70 70 50 Denton 72 88 71 87 71 / 50 30 60 50 40 McKinney 73 88 71 85 71 / 50 30 60 60 40 Dallas 74 90 72 88 73 / 50 30 60 50 40 Terrell 74 88 72 89 72 / 50 30 60 60 40 Corsicana 73 87 72 85 72 / 40 30 60 60 30 Temple 74 90 73 91 73 / 30 30 50 50 20 Mineral Wells 71 88 69 89 70 / 50 30 60 40 30 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 79