927 FXUS64 KSHV 281620 AAA AFDSHV Area Forecast Discussion...UPDATED National Weather Service Shreveport LA 1120 AM CDT Mon Mar 28 2022 .UPDATE... Mostly cloudy to overcast skies persist across most of the forecast area this morning, but ceilings lifted rapidly after sunrise. Latest visible satellite loops indicate the clouds are starting to scatter south of Interstate 20, and these trends should continue with skies becoming mostly sunny this afternoon. A quasi-stationary front has moved farther south of I-20, and this is reflected in a rather strong gradient in the dewpoints, with low to mid 30s in Southeast Oklahoma and Southern Arkansas to 60s across the southern half of the area. The front is still expected to return northward this afternoon. Dewpoints should increase across the northern half of the area as southerly flow returns, but they should mix out farther south with sunshine and vertical mixing. Most of the forecast looks on track today, but some updates were made to the Sky and Dewpoint grids based on the latest trends. CN && .PREV DISCUSSION... /issued 636 AM CDT Mon Mar 28 2022/ AVIATION... Cigs have lifted to MVFR across much of E TX/N LA this morning, and will soon affect the ELD and possibly the TXK terminals through mid-morning before scattering out by mid to late morning. IFR cigs and patchy FG has also developed across portions of the Lower Toledo Bend Country into Cntrl LA, but should not affect the LFK or N LA terminals before improvements are seen later this morning. VFR conditions will return areawide by late morning/midday, with a sct cu field developing in wake of a stationary front located along the I-20 corridor of N LA into extreme NE TX, begins to lift N out of the region by early to mid afternoon. While the cu field should diminish by sunset, the cirrus shield will increase from the W and gradually thicken overnight, with MVFR cigs developing over SE TX/S LA late this evening and spread N into the region overnight, between 07-12Z Tuesday. These cigs will persist through mid to late morning, before returning to VFR. S winds 6-12kts is expected today and tonight, with occasional gusts to 20kts possible over the Wrn sections of E TX. /15/ PREV DISCUSSION... /issued 402 AM CDT Mon Mar 28 2022/ SHORT TERM.../Today through Tuesday/ The morning sfc analysis indicates a stationary bndry extending from just S of the I-30 corridor of NE TX into portions of extreme Nrn LA near/just S of the I-20 corridor, although this bndry has continued to drift a bit SSW across N LA in the last several hours, as weak pressure rises have been noted closer to the sfc ridge axis extending from the Midwest S into the Lower MS Valley/SE CONUS. However, the last sfc obs depict stronger SSW winds over portions of E TX this morning, suggesting that this bndry is on the move along its Wrn flank, with areas of low stratus/FG now developing across Deep E TX/WCntrl LA, and should continue to spread NE S of the front through/shortly after daybreak this morning. Have inserted patchy FG wording into the forecast through mid-morning but will hold off on any Dense FG Adv. for now pending what the FG does through daybreak. The increasing SSrly bndry lyr flow will help to return this sfc frontal bndry back N into Cntrl/Ern OK and AR by afternoon, with the cigs expected to gradually scatter out by late morning/early afternoon, allowing for increasing insolation and warm advection to warm temps to near/lower 80s across much of the region. The NBM has again initialized too low with max temps areawide, and thus have warmed temps some 1-3 degrees areawide, which may not be enough in some areas as what was observed with max temps Sunday especially over E TX. A 40+kt SSWrly LLJ tonight will yield a gradually increasing/deepening low level moisture field across the region, with low cigs developing over SE TX/S LA later this evening, which will quickly spread N into the area after midnight. Min temps tonight may actually be observed around/shortly after midnight, with Srly winds and the increasing low cigs allowing temps to hold steady or slowly rise late. Believe that the pressure gradient will be sufficient enough overnight such that the air will remain mixed to preclude FG development, with the bndry lyr moistening further Tuesday as the pressure gradient tightens with the SSWrly LLJ ahead of the deep opening upper trough that will shift E from the Desert SW through the Four Corners Region/Srn Rockies during the afternoon. A considerable cu and cirrus shield should remain in place throughout the day, but strong Srly winds/warm and moist advection and available insolation beneath the broad ridging aloft in place ahead of this approaching trough should result in temps again climbing to near 80/lower 80s over much of the region, a bit higher than what is depicted in the NBM. Dry conditions will continue given the still shallow low level moisture field, as we await the larger scale forcing ahead of the trough/developing dry line late Tuesday afternoon/evening to initiate deeper convection that will advance E into the area late Tuesday night. 15 LONG TERM.../Tuesday Night through Monday/ Upper ridge axis will have moved well east of our region by Tuesday Night as a potent upper level trough begins moving out of the Intermountain West and into the Great Plains. This trough will be our potential big weather maker during the predawn hours Wednesday Morning across our far northwest zones and across the remainder of our Four State Region during the day Wednesday. By 00z Wed, a well defined dryline should be oriented north to south across OK into NC TX, near or just west of the I-35 Corridor. Much of the warm sector across our western half should be capped ahead of this feature but upper forcing should really begin ramping up during the late evening and especially during the overnight hours Tuesday Night into the predawn hours Wednesday Morning as the upper trough progresses eastward. A linear line of convection should begin developing near or just in advance of the dryline, well to our west Tuesday Evening/Night with this feature expected to rapidly move eastward. The convection is expected to outrun the dryline which should remain near the I-35 Corridor by 12z Wed with the linear line of convection likely entering our far west and northwest zones near or just prior to 12z Wed. SPC currently has our area along and west of a line from Tyler and Dekalb Texas to near Mena, Arkansas in a Slight Risk for severe thunderstorms with bowing line segments producing damaging wind gusts in association with a QLCS the likely storm mode early on. This feature should continue to move rapidly eastward through at least the western 2/3rds of our region by Noon on Wednesday and the eastern 1/2 to 1/3rd of our our region by late morning through the afternoon hours on Wednesday. Should be a well defined cold pool in association with the eastward moving QLCS on Wednesday which suggests damaging wind gusts will continue to be the greatest threat but low level directional shear will be sufficient for embedded QLCS tornadic vorticies as well. In agreement with SPC and their Day 3 discussion that discrete storms will be greatly dependent on just how much instability we see ahead of the QLCS on Wednesday. Deep layer 0-6km Bulk Shear values hint at that possibility which of course combined with strong low level directional shear would pose more of an intense tornado threat but would like to see more instability to see a more discrete storm mode ahead of the much more likely QLCS. Strong cold front in association with the upper trough will eventually catch the dryline to our west and will have pushed through all but our eastern third by 00z Thu with the convection likely east of our region ahead of the cold front. A brief cool down in the wake of this front to end the work week with lows Wed and Thu Nights in the 40s and highs by Friday returning to the 70s across our entire region. There is another upper trough poised to effect our region quickly on the heels of its predecessor Friday Night into Saturday but discrepancies in the medium range pertaining to this troughs amplitude leads to uncertainty concerning pop coverage into Saturday. Split the difference for now between the drier GFS and the much wetter ECMWF which calls for chance pops across our region on Saturday with any precipitation ending to our east Saturday Night and a dry Sunday to finish up the weekend. Did introduce low end chance pops across our western half for Monday in advance of our next trough of low pressure to begin the upcoming work week. 13 && .PRELIMINARY POINT TEMPS/POPS... SHV 83 61 83 65 / 0 0 0 20 MLU 81 60 82 64 / 0 0 0 10 DEQ 78 57 78 60 / 0 0 0 80 TXK 78 60 80 64 / 0 0 0 50 ELD 79 57 81 63 / 0 0 0 10 TYR 83 63 83 61 / 0 0 0 80 GGG 82 63 83 62 / 0 0 0 50 LFK 85 63 85 66 / 0 0 0 40 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 09/04