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Displaying AFOS PIL: AFDSHV Received: 2018-10-17 10:00 UTC
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789 FXUS64 KSHV 171000 CCA AFDSHV Area Forecast Discussion...CORRECTED National Weather Service Shreveport LA 500 AM CDT Wed Oct 17 2018 .SHORT TERM.../Today through Thursday/ Areas of -RA continues to develop/shift E generally between the I-30 and I-20 corridors of E TX, which extends across much of N LA as well this morning. This is in association with weak convergence along and N of the H850 trough, as well as weak elevated isentropic forcing embedded in the SW flow aloft. However, sfc obs indicate the low cigs beginning to lift across SW AR this morning, as drying between the bndry lyr and H925 continues to spill SSW into portions of extreme NE TX to near the AR/LA border. This trend will continue today with the drier air beginning to deepen late this morning through the afternoon across portions of N LA and adjacent sections of NE TX. Convergence along the H850 trough is expected to weaken later this morning, as drier air continues to mix SSW, which should result in the areas of -RA diminishing by afternoon. However, given the current radar trends and the fact that measurable rain is still falling, have increased pops this morning to likely along the I-20 corridor of E TX/N LA, tapering pops down to chance N and S of this area. Have also dropped mention of pops this morning for SE OK/Nrn sections of SW AR, although the short term progs are in good agreement with areas of SHRA currently SW of DFW between MKN and LZZ, lifting NE along a weak inverted mid level trough into portions of NE TX/SE OK/adjacent sections of SW AR. These SHRA will encounter a deeper area of drier air as it approaches the Red River Valley, but still may result in some light QPF this afternoon. Thus, have retained low chance pops this afternoon for much of NE TX/SE OK/SW AR/NW LA, tapering to slight chance elsewhere given that the overall forcing may tap into the high PW air mass S of I-20 that will linger through the afternoon. Any sct -SHRA should diminish this evening as the responsible mid level energy begins to weaken. The progs also depict weak dirty ridging aloft extending NW across much of the area today, as the Wrn Atlantic/Fl Peninsula, and Gulf of MX ridge begins to bridge W. Should see temps climb about 10 degrees today as the -RA gradually diminishes and cigs begin to lift, and have kept readings closer to the Blends/MAVMOS. The wedge of low level drier air is expected to continue backdooring SW across N LA/Lower E TX tonight, although the H850 cigs should not scatter out much farther S than I-20 by Thursday morning. However, weak overrunning looks to commence by Thursday morning, in time as a deeper wedge of elevated moisture originating from the SW Gulf begins to advect N around the Wrn periphery of the ridge. As a result, isolated -SHRA may develop across the SW sections of E TX Thursday morning, with the moisture profile beginning to deepen once again in response to this moisture advection/saturation from the top down from SHRA developing/spreading N across Cntrl and Ecntrl TX. Have increased pops to low chance for the far Wrn counties of E TX Thursday afternoon given the good agreement in light QPF over these areas, while also maintaining a buffer of slight chance pops for SE OK/much of the remainder of E TX. Should see a continued trend of warming (but still below normal) daytime temps Thursday as well, with low level moisture advection expected to increase from the S late Thursday night. This will occur as the closed low indicated on the morning water vapor imagery over Nrn AZ this morning, should begin to slowly lift N into UT tonight, before becoming absorbed into the NW flow aloft by Thursday night. This next trough will begin to amplify ahead of the next shortwave troughing digging SE into the Nrn Plains from Saskatchewan/Manitoba. Thus, overrunning and the eventual increase in large scale ascent will begin to increase resulting in an increase in SHRA as we round out the end of the work week. 15 .LONG TERM.../Thursday night through Tuesday night/ The very persistant upper level low of late will be located just to the North of the Four Corners by late Thursday and is very closely modeled by GFS/ECMWF to open wave and slip into the pattern moving out across the plains while slowly filing the long wave into a more zonal flow across the country by the start of next week. However, as expected this will refocus the tropical connection still lying across Texas back into our area, initially across I-30 for late week. This large area of rain showers will filter down across I-20 overnight and eventually all of the cwa by mid weekend as a now stronger cold front drops down the front range of the Rockies with a 1032mb air mass over IA by sunset Saturday. The result will be rain showers will again work across most of the area Friday and into Saturday with fresh Northerly winds that will drive all the moisture Southward during the afternoon. By far, Sunday is looking to be the much better day this weekend with the still 1028mb high centered over KT/TN on and all of the rich moisture back in the tropics from Brownsville to Miami. The work week starts out dry and below average on temps and now looks to continue as such into midweek before the next Pacific cyclone spins up South of Baja and looms beyond this scope. Meanwhile, a weak upper low will skirt along the Gulf coast from mid to late week, keeping primarily just to the South of our area. This is a little different than recent days and perhaps a chance for us to dry out. /24/ && .PREV DISCUSSION... /issued 1149 PM CDT Tue Oct 16 2018/ AVIATION... For the 17/06Z TAF period, IFR/MVFR cigs continue to plague all sites this evening as light to moderate rain is still ongoing over much of the region. Expect these trends to continue through at least daybreak as cigs may dip even lower with intermittent LIFR conditions at times. Rain should began to taper off during the day on Wednesday, but still cannot rule out some periodic rainy periods as SW flow aloft shifts more westerly. Cigs will begin to finally improve as well, likely seeing MVFR and some low VFR cigs late in the period. N/NE sfc winds will prevail with speeds from around 6-12 kts through much of the period. /19/ && .PRELIMINARY POINT TEMPS/POPS... SHV 58 55 64 55 / 60 20 10 10 MLU 58 54 68 55 / 60 10 10 10 DEQ 62 52 62 52 / 30 20 10 30 TXK 57 51 62 51 / 40 20 10 20 ELD 58 51 64 52 / 40 20 10 10 TYR 56 54 63 52 / 60 20 30 10 GGG 58 55 63 54 / 60 20 20 10 LFK 58 56 68 57 / 30 20 20 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 15/24