National Weather Service Raw Text Product
Displaying AFOS PIL: AFDFWD Product Timestamp: 2019-01-23 21:00 UTC
Previous in Time Latest Product Next in Time
View All KFWD Products for 23 Jan 2019 View All AFD Products for 23 Jan 2019 View As Image Download As Text
534 FXUS64 KFWD 232100 AFDFWD Area Forecast Discussion National Weather Service Fort Worth TX 300 PM CST Wed Jan 23 2019 .SHORT TERM... /Through Tonight/ Rather tranquil weather will persist through tonight, with the only notable change being a continued decrease in wind speeds and a gradual shift in direction. A 250mb northwesterly jet centered over Idaho will maintain a progressive pattern, forcing the central-US trough (which yielded our local pockets of sleet last night) to transit downstream. Building heights in the wake of this trough will bring a surface ridge axis across all of Central and North Texas by late evening, resulting in flow backing to a light southerly direction. Despite these southerly winds, light speeds and a very dry column (e.g., precipitable water values near the 5th percentile for the date) should still solidly support radiational cooling, and many locations are expected to experience a freeze again tonight. Low- lying, sheltered areas will likely realize the coldest conditions, owing to localized cold-air drainage. Picca && .LONG TERM... /Thursday onward/ Cold and dry will be the main theme for the long-term forecast. Morning 500 mb analysis showed a deep trough in place across much of the interior CONUS. At the surface, high pressure extends from the Great Basin southeastwards across the Desert Southwest and into the Lone Star State. This combination is leading to cool, but dry conditions across much of the Southwest and Southern Plains. An upper-level pattern characterized by a deep upper-level trough will persist throughout the next seven days, resulting in continued cold anomalies across much of North America east of the Rocky Mountains (see the latest CPC outlook for Days 6-10). The GFS and ECMWF are in strong agreement as to the big picture details, and to some degree, even the finer points in the forecast. These finer points in the forecast will be dictated by the timing of various shortwave troughs and potential vorticity anomalies propagating through the longwave trough. The first such feature will move into the Southern High Plains on Thursday. At the surface, a cold front will push through, reaching our northwestern counties by early afternoon, and clearing our southeastern counties by midnight. Winds may become northwesterly a little ahead of the main front within a pre-frontal trough. Highs should reach the 50s ahead of the front, with lows falling back into the 20s by Friday morning. Moisture ahead of the front looks quite minimal, so PoPs will be near zero for Thursday. On Saturday, another shortwave trough will propagate through the persistent longwave trough, but at a far lower latitude (i.e. south of the International Border). This will result in the development of a weak surface low that will track along the Rio Grande. Precipitation will likely develop in the baroclinic zone to the northeast of this surface low, but most of this rain should remain to our southwest. It will be possible that some light rain sneaks into our southern and southwestern counties however, thus lower end PoPs were carried for Saturday, with chance PoPs indicated south of a Eastland to Groesbeck line. A brief warm-up looks to commence on Sunday and into Monday as a surface low develops over the Northern Plains, leading to southerly winds and warm air advection across North and Central Texas. This warm-up looks to be short-lived however. A strong Arctic cold front will come blasting through late Monday afternoon as a potent PV anomaly swings through the Central Plains. Gusty northwesterly to northerly winds and rapidly falling temperatures can be expected behind this cold front. Moisture may be a little deeper ahead of this front however thanks to the warm air advection on Sunday and into early Monday. Some light precipitation may develop over the eastern third of our forecast area. This precipitation looks to be predominantly liquid rain, but a brief transition to VERY LIGHT snow will be possible early Tuesday morning before the moisture is evacuated to our east. The best chances for light snow will be the farther north and east one goes, with light snow chance PoPs carried northeast of a Sherman to Greenville line. /Extended Outlook/ CPC outlooks indicate elevated probabilities of below normal temperatures through the end of January as a negative phase of the Arctic Oscillation (AO) is forecast to persist through the coming weeks. A negative phase AO typically results in a more amplified pattern with deep upper-level troughs becoming established across much of North America (as is the case currently), and southward migrations of the Polar Vortex. What this means for us in North and Central Texas is that cold air deliveries from the Arctic become more frequent, and perhaps more sustained, leading to the longer term cold anomalies that we have been seeing (and that look to persist for some time). The magnitude of how cold it gets can vary however, and depends greatly on where the axis of these upper-level troughs become established, with a farther west axis typically resulting in more extreme cold across the Southern Plains, and a farther east axis resulting in extreme cold across the Midwest and Northeast. With respect for wintry precipitation potential, this Arctic air tends to be quite dry, so despite the increased risk for colder than normal temperatures, there is not necessarily an increased risk for winter weather; however, since cold air is (obviously) one of the key ingredients for winter weather, we will have to be mindful of any passing storm systems that may introduce lift and moisture into this cold air. The key message at this point is to look for continued near to below normal temperatures in the extended forecast, with a reduced risk for widespread precipitation events (wintry or otherwise). Godwin && .AVIATION... /Issued 1206 PM CST Wed Jan 23 2019/ /18Z TAFs/ No major concerns through the TAF periods of our local airports. Winds will remain occasionally gusty (upwards of 20-25 kt) from the northwest early this afternoon. However, gusts should subside towards 21-00Z. Winds will further weaken and back towards a southerly direction thereafter, and a return to south flow ops is possible by late evening (02-05Z). Winds remain light and southerly through much of Thursday. Only exception involves the 30-hour KDFW TAF -- a cold front is expected to cross the terminal around 21-00Z, with winds switching to the north/northeast around 10 kt. VFR tonight into tomorrow. Picca && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 32 56 28 46 35 / 0 0 0 0 5 Waco 27 57 30 49 35 / 0 0 0 0 5 Paris 29 53 25 42 30 / 0 0 0 0 5 Denton 26 55 26 46 32 / 0 0 0 0 5 McKinney 25 55 27 44 32 / 0 0 0 0 5 Dallas 32 57 29 46 35 / 0 0 0 0 5 Terrell 27 55 28 46 33 / 0 0 0 0 5 Corsicana 33 56 30 46 35 / 0 0 0 0 5 Temple 28 58 32 50 35 / 0 0 0 0 0 Mineral Wells 27 57 26 48 32 / 0 0 0 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 11/82