Area Forecast Discussion
Issued by NWS
Issued by NWS
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
43
549 FXUS64 KLUB 091759 AFDLUB Area Forecast Discussion National Weather Service Lubbock TX 1259 PM CDT Tue Jul 9 2024 ...New AVIATION... .SHORT TERM... (Today and tonight) Issued at 246 AM CDT Tue Jul 9 2024 06Z upper air analysis reveals a positively-tilted shortwave trough ejecting over the Mississippi River Valley, with its base beginning to approach central North Texas as per recent water-vapor imagery. Farther west, a subtropical ridge was centered over the Mojave and Sonoran Deserts, where a 250 mb jet streak that was objectively analyzed on the 09/00Z upper air map data has weakened to 40 kt and is accompanied by an ill-defined vorticity lobe rotating over the Cricket Mountains. Increasing NVA/subsidence on the backside of the mid/upper-level trough continues to advect into the region which has resulted in excellent boundary-layer cooling this early morning; and patchy, small areas of mid-level stratus continue to linger across portions of the extreme southern TX PH and South Plains with an otherwise crystal clear sky. At the surface, a quasi-stationary front is located far to the south of the CWA and bends northeastward across the Edwards Plateau before extending northward to the east of the 100th meridian. West Texas Mesonet (WTM) data analyzes an anticyclone centered to the northeast of LBB, and between Floydada and Ralls; and winds were calm across the entire CWA. Leaf wetness on the WTM data was near zero except for a few locales despite relative humidity moistening to above 80 percent, and unless there is a spike in leaf wetness measurements, patchy fog appears to be a very low probability through sunrise. Trends will continue to be monitored. The benign surface pattern will remain intact throughout the scope of the short-term period, with winds remaining calm today as the anticyclone slowly rotates eastward into the Red River Valley. The mid/upper-level trough will be slow to pivot eastward throughout the day today as a subtropical ridge amplifies across the eastern Atlantic Basin, with its base forecast to still be present over central North Texas by 10/00Z this evening; however, the 250 mb jet streak embedded within the trough will continue to translate northeastward as it interacts with and absorbs Tropical Depression Beryl. Northwesterly flow will persist over the region today with boundary-layer heights capped near 700 mb beneath warm mid-levels and a slim, residual, elevated mixed layer (EML). Full insolation will result in a well-mixed boundary-layer developing beneath the cap, with Inverted-V profiles evolving as temperatures rise into the upper 80s and lower 90s area-wide from the gradual increase in geopotential heights as the subtropical ridge over the Mojave and Sonoran Deserts expands eastward. Scattered thunderstorms are forecast to develop far northwest of the CWA this afternoon as the 250 mb jet streak noses over the Sangre de Cristo Mountains and into the western High Plains. The expectation is for this complex to advect southeastward along the mean wind vector and arrive near the TX/NM state line towards 10/00Z. However, boundary-layer decoupling, in addition to the eroded EML, should result in the complex of storms to begin weakening with coverage becoming more-widely-scattered to perhaps even isolated as it crosses into the CWA. Convection will become elevated after sunset, which will eliminate the potential for gusts; and updrafts should begin to struggle to produce lightning after 10/05Z (midnight CDT) with showers lingering across the far western South Plains by that time. The highest PoPs, which were capped at 30 percent, remain along and west of the HWY-385 corridor as the decaying complex is forecast to move southward after dark. Warmer temperatures will follow heading into Wednesday morning as anvil debris minimizes the loss of longwave radiation amidst light and variable winds. Sincavage && .LONG TERM... (Wednesday through Monday) Issued at 246 AM CDT Tue Jul 9 2024 The subtropical ridge over the western U.S. will continue to wobble eastward on Wednesday as its position is modulated by a shortwave trough digging into the Alexander Archipelago. Meanwhile, the positively-tilted trough will become more-basal as its associated jet streaks translate over the Ohio River Valley, with a corridor of largely difluent, mid-level flow advecting into the CWA throughout the day. Several smaller-scale perturbations and ill-defined vorticity lobes will arc over the apex of the ridge and propagate southeastward within the eastern tranche of the expanding ridge from the west, and with a more-northerly component to the mid-level flow, the EML should improve in size and depth compared to Tuesday as forecast soundings indicate mixed-layer parcels yielding nearly 1,500 J/kg of CAPE. The boundary-layer will become well-mixed once again as slightly hotter temperatures are expected as surface flow veers to the southwest, further eroding the minimal MLCINH in place during the early afternoon hours. Scattered, multi-cellular clusters are forecast to develop across the Caprock and into portions of the Rolling Plains on Wednesday afternoon and into the evening; and storm motions will be governed by propagation from cold pools versus advection with the mean wind aloft. Inverted-V boundary-layer profiles beneath water-loaded updrafts will yield the possibility for isolated wind gusts in excess of 60 mph to occur with the organized clusters. Localized flooding will be possible due to the slow movement of storms. The spatiotemporal coverage of storms will begin to wane after dark as nocturnal stabilization of the boundary-layer occurs. By Thursday, mid/upper-level flow will dampen substantially as the waveguide of the basal troughing continues to attenuate from the amplifying ridges over the western U.S. and eastern Atlantic Basin. Diffuse surface troughing may serve as a focus for convective development across portions of the South Plains on Thursday afternoon, with pulse-like, single- and multi-cellular storms possible as the mean wind vector is nearly zero given the position of the latter synoptic-scale features. The blended PoPs were maintained for portions of the South Plains on Thursday as the barotropic airmass maintains a similar thermodynamic profile at the surface and aloft compared to the prior days. Doldrum-like conditions will follow heading into Friday and next weekend as little change occurs with the airmass as the subtropical ridges over the western U.S. and eastern Atlantic Basin begin to phase. Sincavage && .AVIATION... (18Z TAFS) Issued at 1230 PM CDT Tue Jul 9 2024 Overall a quiet day with calm winds and a shallow cumulus field forming throughout Western Texas. There is a chance of thunderstorms out of eastern New Mexico around sunset, which could shift wind directions and raise wind speeds. However, storms will struggle to make it into the Plainview and Lubbock aerodromes, and are not expected to affect Childress. Watson && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...09 LONG TERM....09 AVIATION...26