100 FXUS64 KFWD 030931 AFDFWD Area Forecast Discussion National Weather Service Fort Worth TX 331 AM CST Sun Feb 3 2019 .SHORT TERM... /Through Tonight/ In wake of yesterday's departing shortwave trough, weak upper ridging will prevail today. Meanwhile, another upstream shortwave will traverse the Rockies today, leading to increased lee cyclogenesis. This pattern will keep the Southern Plains within a warm advection regime with moist southerly flow prevailing. Widespread low stratus and some fog exists across the forecast area this morning with ample moisture within the lowest 3 kft. While visibilities may occasionally drop to around a mile or less throughout this morning, widespread dense fog is not expected at this point. The thickest fog is generally expected across parts of Central Texas through mid morning. Otherwise, continued warm advection has supported some very light showers or sprinkles across our southeastern zones overnight which may linger through the morning before exiting to the east. Outside of these isolated showers and some occasional mist or drizzle this morning, most areas will remain dry today. The high dewpoints and widespread clouds have kept temperatures mild overnight, with most locations beginning the day in the mid 50s to near 60 degrees. Later today, low-level flow will veer slightly in response to the aforementioned increasing cyclogenesis to our northwest. The slight westerly component within the low- level flow should help to gradually erode the cloud deck from west to east throughout the day while an ill-defined Pacific front boundary drifts slowly eastward towards the forecast area. With skies expected to go broken or scattered west of I-35 this afternoon, temperatures should be capable of climbing well into the 70s, or even near 80 degrees across some of our western counties. Farther east, stubborn cloud cover should prevent temperatures from climbing out of the mid 60s to near 70. The tightening surface pressure gradient will also mean increased wind speeds, with winds of as high as 20-25 mph possible this afternoon. As the low-level cloud deck erodes later today, additional mid- level clouds will spread into the area from the west later this afternoon and evening. While this may lead to the appearance of some echoes on radar, precipitation from this cloud deck appears rather unlikely with some much drier air located just beneath the cloud base. These clouds along with lingering low stratus in East Texas should help keep overnight lows on the warm side, in the mid 50s to low 60s. Fog may redevelop across some of our southern and eastern zones by daybreak Monday where dewpoints will climb into the low 60s overnight. However, persistent winds around 10 mph should prevent it from becoming widespread or dense. -Stalley && .LONG TERM... /Monday through Saturday/ Well above normal warmth is anticipated through at least mid-week. Morning to early afternoon cloud cover/drizzle is anticipated with low rain chances across parts of the area. From mid-week and into next weekend, conditions will change quite noticeably as a strong front plows southward through the area. Increased chances for showers and storms will accompany this front along with much colder conditions. Rain chances will linger into next weekend. Monday and Tuesday---Rich boundary layer moisture will be transported northward beneath a decent capping inversion. While lapse rates are somewhat steep above the cap, there appears to be little in the way of forcing for ascent. This should mean only drizzle/fog in the morning hours on Monday and again on Tuesday, mainly for areas near and southeast of a Lampasas to Waco to Canton line. Drizzle/fog may be possible elsewhere, but at this time, the best potential is across the aformentioned geographic area. On Monday afternoon, surface to 850mb flow will veer sharply ahead of cold front that is forecast to dive southward out of the Central Plains. All indications are that this front should remain north of the Red River. The veered low levels should help to scour out low level moisture (and thus drizzle/fog and clouds) and will likely promote rapid warming due to increased adiabatic compression. High temperatures will be greatest west of I-35 (highs in the low 80s) with slightly cooler conditions across East Texas(highs in the low 70s) where cloud cover will linger and the downslope component will not be as great. Tuesday should feature another day of unseasonably warm conditions, though highs will be tempered some thanks to the greater degree of cloud cover. Low level flow does not appear to veer as sharply in model wind fields...with the exception being across the Big Country where temperatures may still climb to near 80 degrees. The depth of moisture should increase some and capping will not be as strong with backed low level flow, especially across East Texas. Forcing for ascent---outside of WAA---appears meager and I've undercut blended model guidance and will only advertise a 10-15 PoP with a few showers. Otherwise, there will be a risk for a few pockets of drizzle/fog, mainly during the morning hours. Late Tuesday, some guidance suggests that some weak convection will be possible along the Red River and across parts of East Texas. It appears that some of the model guidance may be attempting to produce some precipitation due to modest surface convergence along the front discussed above. For now, I'll maintain a rain-free forecast during this time for a couple of reasons. 1) Forcing for ascent appears meager on the synoptic scale and 2) It's a little difficult to identify any mesoscale influences that would result in rain and/or storms. As we get closer to Tuesday, we should have a better handle on 2) with the assistance from hi-res NWP. Wednesday and Thursday---Wednesday will be a little cooler thanks to denser and more widespread cloud cover. Capping will be reduced further and WAA should be enough to kick off some isolated to widely scattered showers during the morning and afternoon hours on Wednesday. Slightly stronger breezes are expected on Wednesday as the surface pressure gradient tightens some. Rain chances will increase quickly Wednesday night and into Thursday with the approach of our next big cold front. Model guidance has converged with respect to the timing of FROPA. The 00 UTC GFS is now slightly faster than the 00 UTC ECMWF and Canadian. PoPs advertised by the blends seem reasonable, though I'll cap rain/storms chances off at 60% given that there will likely be some spatiotemporal changes to the PoP forecast. There appears to be sufficient instability for thunderstorms late Wednesday and into Thursday. CAPE values will near 1500 J/kg with deep layer shear values on the order of 40 knots. These ingredients could support some organized storm modes, however, there are a few of things that could preclude a severe weather episode. The first is the speed of the front with respect to the storm motion. With deep layer shear vectors largely parallel to the front, it's possible that updrafts will be undercut quickly. Finally, the time of day may be slightly unfavorable for surface based convection. In addition, if cloud cover hangs tough through the day, the aformentioned forecast CAPE values may be overdone. Lapse rates do climb close to 7 C/km, however, and if storms do realize forecast CAPE values and can remain out in the warm sector away from the front, there could be a threat for strong to severe storms. Friday and Beyond---After above normal warmth, Friday and into the weekend will see much colder conditions. Strong north winds below 850mb should ensure that colder air filters southward into North and Central Texas. 700mb flow, however, appears as if it will quickly become southerly...possibly in response to the thermally direct circulation associated with the entrance region a strong upper level jet. This would result in a decent amount of isentropic upglide atop the colder near surface layer and thus a good setup for post-frontal stratiform precipitation. Previously, the GFS and some of its ensembles were the lone camp that advertised this scenario. Closer inspection of the latest ECMWF guidance is more in line with the GFS/GEFS solutions and I've nudged PoPs upward some late Friday and into Saturday. At this time, it appears that most locations should be warm enough such that all precipitation remains just a cold rain. The exception to this may be along the Red River, though moisture depth likely would support more in the way of freezing drizzle. For now, I'll keep the entire forecast void of any winter precipitation, but it'll be something to keep an eye on. Bain && .AVIATION... /Issued 1128 PM CST Sat Feb 2 2019/ /06Z TAFs/ Stratus will continue to surge northward overnight in response to deepening surface low pressure across the Central and Southern High Plains. MVFR to high end IFR ceilings will slowly lower through the night with all TAF sites falling below 1000 ft before sunrise. Visibility will also fall between 3 and 5 miles but breezy southerly winds overnight/Sunday morning should prevent dense fog from developing. Ceilings will slowly lift by mid morning but will remain below 3000 ft until mid afternoon Sunday. A few sprinkles or brief light rain will be possible through the night generally east of Waco so no impacts to the TAF sites are anticipated. A south to southeast wind will prevail through Sunday evening at speeds between 8 and 13 knots tonight and 12 and 16 knots on Sunday along with some higher gusts. 79 && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 73 60 80 60 76 / 5 0 0 5 10 Waco 73 61 79 60 76 / 10 0 0 5 10 Paris 68 61 76 58 73 / 10 5 0 10 20 Denton 72 58 78 57 76 / 5 0 0 5 10 McKinney 70 59 77 58 75 / 10 0 0 5 10 Dallas 72 60 80 61 76 / 5 0 0 5 10 Terrell 71 61 77 60 74 / 10 0 0 10 10 Corsicana 71 63 78 61 76 / 10 5 0 10 20 Temple 73 61 78 60 76 / 5 0 0 5 10 Mineral Wells 74 56 81 56 78 / 0 0 0 0 10 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 24/26