Area Forecast Discussion
Issued by NWS Dallas/Fort Worth, TX
Issued by NWS Dallas/Fort Worth, TX
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
635 FXUS64 KFWD 271859 AFDFWD Area Forecast Discussion National Weather Service Fort Worth TX 159 PM CDT Mon May 27 2024 ...New Short Term, Aviation... .SHORT TERM... /NEW/ /Today and Tomorrow/ Highlights... There is another threat of severe weather today, with isolated to scattered thunderstorms expected to develop this afternoon. The main threats will be large hail and damaging wind gusts. There is a low (but not quite zero) tornado threat. Additional storms will form late tonight and tomorrow. There will be a low severe risk early in the day, but a higher risk of severe weather as additional storms move into the area late tomorrow afternoon. Forecast Discussion... There are a couple boundaries in the area that we`re monitoring for storm development today. The first, and most notable, is a stationary front draped over the Metroplex. The boundary currently resides from about Jack County through DFW to Tyler. We have some shallow cumulus along the boundary now, but the updrafts have been weak. The second boundary is evident by a dewpoint gradient across the southern Big Country and Western Central Texas. This boundary is harder to identify in surface observations, but there is a cluster of cumulus that has developed in its vicinity. Plentiful insolation will result in a deeply-mixed boundary layer this afternoon, helping to erode the capping that was evident on the morning FWD sounding. Recent ACARS/aircraft soundings have shown that the cap still exists, however it is much weaker than earlier in the day. With the combination of weak confluence or moisture convergence near the boundaries, convective initiation will be possible after about 2-3 PM. Moreover, this morning`s observed sounding`s convective temperature was 97 F, which is already being met or close to being met in/near the Metroplex as of 1 PM. All of this to say, it looks more like than not that we will at least see convective attempts near the Metroplex and Western Central Texas this afternoon into the evening. The coverage of storms today should be isolated to scattered. Although we will have a focused source of surface ascent, negligible mid- level ascent should preclude widespread thunderstorm development. Since surface heating is a primary forcing mechanism, most of the storms should dissipate after sunset with the loss of heating for most of the night. The atmosphere remains highly buoyant, largely thanks to very high dewpoints across the region. DFW Airport`s dew point between 7-11 AM was 78 F...a daily record (our records go back to 1947). It has since mixed down to 73 F, a further sign of diurnal heating working to lift parcels near the stationary front. Widespread dewpoints of 77-80 F remain across most of the area south of the stalled front. This hot and humid airmass resides underneath cool mid-levels, with "above the cap" lapse rates of 8-10 degC/km. Forecast soundings indicate ML CAPE values of 4-5000, with hail growth zone CAPE values near 1500 J/kg. The shear isn`t great, but nearly straight hodographs will favor splitting storms yet again. After a storm splits, it will usually have a higher severe potential. The only way a tornado would be able to develop is if a storm happens to move directly along a surface boundary--either the stationary front or an outflow boundary. This would locally enhance the low-level wind field and possibly allow for a tornado to develop with a strong supercell. The chance of this occurring is low, but not completely out of the realm of possibility. The front will remain stalled across North Texas overnight, with the 925/850 front lingering over southern Oklahoma. A shortwave trough will move overtop of the fronts in the early morning and develop thunderstorms near the Red River. These storms should move southeast through the morning, likely creating a strong cold pool by mid-day. We are not fully confident of where and when storms will develop...but are confident we will have storms develop early in the day. The afternoon forecast will heavily depend on how the morning storms evolve, so for now, we have broad-brushed 30-60 PoPs across the region after 1PM tomorrow. There will be a severe threat with the morning activity, mainly a hail and wind risk. If training storms are able to develop, there will also be a flash flood threat as well. Heat/Temperature... It is HOT outside. Most temperature readings are in the low to mid 90s at this time. Temperatures should peak a few degrees higher in the next couple hours. When you combine the moisture in the air, heat index values of 105-110 are expected across much of the region today. Since our Heat Advisory criteria (heat index >= 105) has a two consecutive day requirement, we have not expanded the advisory west of I-35 or north of I-20. Tomorrow`s temperatures will finally be closer to the seasonal normals due to the cloud cover and increased rain chances. Bonnette && .LONG TERM... /Issued 308 AM CDT Mon May 27 2024/ /Tuesday Evening and Beyond/ An active northwest flow pattern will set up over North and Central Texas by midweek as the region becomes sandwiched between a developing ridge over portions of the Desert Southwest/northern Mexico and troughing over the Great Lakes region. An initial shortwave perturbation looks to shift over a sharpening dryline late Tuesday afternoon/evening, initiating isolated to scattered convection over portions of West Texas and the Big Country. This activity will likely develop initially as supercells before growing upscale into a cluster of cells or possibly an MCS. With a northwesterly mean cloud-layer wind and a 25-35 southeasterly LLJ, this complex of thunderstorms will rapidly shift southeast toward our forecast area late Tuesday evening into the overnight. Where the initial convection occurs will play a large part in determining where this complex tracks Tuesday evening/night. However, there are several signals that our western Central Texas counties could witness the brunt of this complex`s impact. These convective systems tend to track along instability gradients, and most guidance right now places that SBCAPE gradient/weak, stalled frontal boundary generally along/south of the I-20 corridor Tuesday night. This track over western Central Texas and the Hill Country may also be reinforced by outflow from thunderstorms near the Red River Valley earlier in the day. Damaging wind gusts along the leading edge of this complex and isolated hail will be the primary hazards. Latest high-resolution guidance currently places an area along/southwest of a Breckenridge- Hillsboro line in the track of this potentially severe line of storms. The portion of this complex north of the instability gradient will likely be sub-severe with a lack of surface-based instability present. PWATs approaching 1.9-2.1" and warm cloud depths greater than 15,000ft will make these thunderstorms very efficient rainfall producers and several locations beneath these storms could pick up a quick 2-3" of rain. Continue to monitor the forecast over the next couple of days as we further refine location and timing details. This active pattern will continue through the rest of the work week with daily chances for thunderstorms over portions of North and Central Texas through at least Saturday. Coverage Wednesday may be more isolated, but the next chance for more widespread rainfall looks to arrive late Thursday into Friday as another compact shortwave progresses overhead through the northwesterly flow aloft and the aforementioned stalled frontal boundary lifts north toward the Red River enveloping most of the region in moderate surface-based instability. Severe weather will be possible at times. Additionally, multiple rounds of heavy rainfall will increase the flooding threat, especially over already saturated areas. Otherwise, temperatures will be slightly tempered by clouds and precipitation with widespread afternoon highs in the 80s and low 90s and overnight lows in the mid-60s to low 70s. Langfeld && .AVIATION... /NEW/ /18Z TAFs/ VFR and southeast flow should prevail this afternoon. A weak surface front in the area may allow for thunderstorms to develop over D10 after about 21-22Z through 02-04Z this evening. The chance of an isolated storm developing appears more likely than not, however we are still not exactly sure where the first storm will develop. For now, we only have VCTS in the TAFs...but may need to add a TEMPO or remove VCTS as the afternoon progresses. The chance of direct terminal impacts is about 30%. A cluster of storms is forecast to develop over southern OK late tonight and early tomorrow morning. It should approach the area close to the morning push. These storms would also cause a change to north flow for most of the day. We are not highly confident of where and when storms will develop, so similar to today`s storms, we will have to closely monitor new data as it comes in and be quick to update the forecast if our thinking changes. Bonnette && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 96 72 89 71 83 / 20 30 50 60 50 Waco 93 72 89 71 83 / 20 20 50 60 50 Paris 94 67 84 66 79 / 0 30 40 40 50 Denton 97 70 86 68 81 / 20 30 50 60 50 McKinney 95 69 86 68 81 / 20 30 50 50 50 Dallas 97 71 89 71 84 / 20 30 50 60 50 Terrell 93 69 88 68 82 / 20 30 50 50 40 Corsicana 92 72 89 71 85 / 20 20 50 50 50 Temple 94 73 90 71 84 / 20 20 40 50 50 Mineral Wells 96 70 89 68 82 / 20 20 60 70 50 && .FWD WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 8 PM CDT this evening for TXZ135-145>148- 158>162-174-175. && $$