Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/29/21

Area Forecast Discussion
National Weather Service Corpus Christi TX
721 PM CDT Wed Apr 28 2021 .AVIATION... /00Z TAFs/ Gusty SE winds with gusts of 20-30 KTs this evening gradually weakening around 06Z. MVFR CIGs expected to develop near the coast over the next few hours, with lowering CIGs toward COT/LRD toward and after 10Z. Focus switches to the storms moving out of Mexico. Expecting most activity to remain north of LRD-COT due to strong capping over the region, but will monitor for any development farther south that could potentially affect the western sites. For now, will hold VCSH at COT for this evening. A front will move south through tonight and bring showers and possible thunderstorms. Have added at least VCSH for ALI/VCT/CRP after 06Z as thunder may be a bit more isolated. Rain chances should begin to taper off through the late afternoon with CIGs lifting to VFR, with the exception of MVFR CIGs lingering a bit longer near COT. && .PREV DISCUSSION... /Issued 351 PM CDT Wed Apr 28 2021/ SHORT TERM (Tonight through Thursday Night)... One final shot for severe storms exists tonight across portions of La Salle and Webb Counties, although the latest mesoanalysis is not looking too supportive for this in the coming hours. Even with strong heating in place across our western counties, a complete lack of boundary layer cumulus says the cap is still too strong. This is not the case farther up the Rio Grande where a mesolow is evident on visible satellite over Maverick County complete with clusters of agitated cumulus. So the best storm chances should hold NW of the Brush Country this evening, although the HRRR and a few other CAMs have suggested a lone cell or two developing in Webb and Duval Counties this evening with the arrival of an upper speed max. Interestingly, this speed max is confirmed on satellite with a recent uptick in cirriform clouds crossing Laredo, yet the we feel the cap is still too strong at this time for convective initiation in these areas. This should change later tonight over the northern Brush Country as the southern fringes of convection move closer ahead of a Pacific cold front. Overall, PoPs were trimmed lower tonight through the day tomorrow as ascent remains shallow along the slow-moving front. Shallow showers may be the dominant mode along this front, but as this front temporarily stalls over the Coastal Bend Thursday afternoon we should see convective temps met at times which would open the door to some CAPE. Otherwise, the front should finally nudge into the coastal waters Thursday night ahead of light northerly flow. Rain chances should expand to beyond the front late in the night as stronger SW flow overspread the region ahead of a stalled upper low to our west; however, some residual dry slotting may keep the column aloft too dry until much stronger ascent arrives early in the long term forecast. Lastly, minor coastal flooding is again on tap late tonight/early Thursday morning during high tide given favorable swell periods, moderate to strong onshore flow and a recent full moon. LONG TERM (Friday through Wednesday)... Latest model runs are a bit more in agreement with an upper level cut off low developing and meandering west of the area Friday and Saturday. This will keep rain chances in the forecast into the weekend. PWATs remain high with around 1.5 inches near the Rio Grande to around 2 inches along the coast. The deep abundant moisture will combine with a series of embedded short waves tracking around the main upper low to generate scattered convection Friday. Mid level instability and the upper support warrants a mention of thunderstorms. Chances look better by Saturday as a warm front/surface trough works its way north across the area. Surface based CAPE increases to moderate values. RRQ of upper level jet is progged to be over the CWA Sat. These conditions could lead to some strong storms Saturday. Rain chances decrease from west to east Sunday as the upper low moves east of the area with dry conditions expected through next Tue. With expected cloud cover and rain chances, weekend high temps will be cooler. A warming trend will begin Sunday as the warm front lifts north of the area. Triple digit temps are expected out west by early next week. MARINE... Strong onshore flow this evening will weaken to moderate levels over the bays and nearshore waters toward midnight, and the open waters early Thursday morning. A slow-moving cold front will approach the waters Thursday afternoon before moving into the waters Thursday night ahead of weak northerly flow. Isolated to scattered showers and thunderstorms are expected near this front. Weak to moderate offshore flow will continue Friday, then become onshore over the weekend. Weak to moderate northeast to east flow can be expected Friday and Saturday, becoming southeast by Saturday night. Weak to moderate onshore winds on Sunday will increase to more moderate levels Sunday night through Monday. Scattered showers and thunderstorms are possible late in the week and through the weekend. Drier conditions can be expected early next week. && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 74 87 69 82 63 / 20 20 40 40 50 Victoria 73 83 68 81 63 / 30 30 40 40 40 Laredo 74 94 70 84 64 / 20 10 30 40 50 Alice 73 93 68 84 62 / 20 20 40 50 50 Rockport 73 84 69 81 65 / 20 20 40 40 40 Cotulla 73 92 67 85 63 / 30 20 30 40 50 Kingsville 74 91 69 82 63 / 20 20 40 50 50 Navy Corpus 74 82 70 79 66 / 10 20 40 40 50 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...Wind Advisory until 7 PM CDT this evening For the following zones: Bee...Coastal Kleberg...Coastal Nueces...Coastal Refugio...Coastal San Patricio...Goliad...Inland Calhoun... Inland Kleberg...Inland Nueces...Inland Refugio...Inland San Patricio...Victoria. High Rip Current Risk through Thursday morning For the following zones: Aransas Islands...Calhoun Islands...Kleberg Islands...Nueces Islands. Coastal Flood Advisory from 4 AM to 10 AM CDT Thursday For the following zones: Aransas Islands...Calhoun Islands... Kleberg Islands...Nueces Islands. GM...Small Craft Advisory until 7 AM CDT Thursday For the following zones: Coastal waters from Baffin Bay to Port Aransas out 20 NM...Coastal waters from Port Aransas to Matagorda Ship Channel out 20 NM...Waters from Baffin Bay to Port Aransas from 20 to 60 NM...Waters from Port Aransas to Matagorda Ship Channel from 20 to 60 NM. Small Craft Advisory until 11 PM CDT this evening For the following zones: Bays and Waterways from Baffin Bay to Port Aransas...Bays and Waterways from Port Aransas to Port O`Connor. && $$ CB/85...AVIATION
Area Forecast Discussion
National Weather Service State College PA
1120 PM EDT Wed Apr 28 2021 .SYNOPSIS... A stalled front will remain near the New York border tonight, then an area of low pressure approaching from the midwest will lift across northern Pennsylvania on Thursday. An upper level trough will swing over the region Friday, then high pressure will build in on Saturday. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Quasi-stationary front remains draped from Lake Erie into central NY state late this evening. A ribbon of high pwats pooling south of this boundary, combined with a weak shortwave approaching from the lower Grt Lks, will keep the chance of showers in the forecast overnight, mainly over the northern tier counties. A few lightning strikes still noted at 03Z across the northern tier, where some minimal cape on the order of about 500 J/kg persists. RAP cape fields indicate a few lightning strikes will remain possible up there well into the night, as there is little room for additional cooling based on current dewpoint depressions. A developing surface wave over the Mississippi Valley is progged to track northeast overnight. Strong isentropic lift at nose of associated low level jet should arrive over the western half of Pa toward dawn. Thus, have increased POPs toward daybreak over the western counties. It will be an unseasonably warm night under mostly cloudy skies south of the stalled front. Lows are expected to range from the low to mid 60s in most spots. However, the quasi-stationary front will likely dip just south of the NY border overnight, resulting in lows in the upper 50s along the northern tier. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/... Thursday will feature more widespread shower activity, as the aforementioned sfc wave deepens as it slides ENEWD along the aforementioned frontal zone draped across NW/Ncentral PA. Categorical POPs are supported throughout most of central PA. However, the steadiest rain should fall across the extreme northwest part of the forecast area, where fgen forcing is strongest at nose of low level jet. Elsewhere, the rain should be showery in nature. Latest HREF and operational runs indicate rainfall of around 1 inch across the northern tier, with only a tenth of an inch or less across much of the Lower Susq Valley. Modest instability will exist to the south of the frontal zone across the southern third of CPA tempered by antecedent precipitation and/or abundant cloud cover, but deep shear profiles will still be rather strong. Day2 MRGL outlook has been suppressed slightly southward to cover the southern third of the area as a result. The potential exists for an isolated strong storm Thursday afternoon/evening. A cold front trailing the sfc low will traverse the area Thursday night with showers fading into early Friday morning in cooler post-frontal NW flow. Latest model guidance shows the low intensifying into New England on Friday. A tightening p-gradient and reinforcing shortwave/surge of CAA should translate into a period of strong gusty NW winds. Similar to the evening shift Tue, the day shift Wed also nudged gusts above the NBM 90th percentile into the 35-40 mph range approaching advy levels based on deterministic fcst soundings. Friday is the last day of April 2021 and it will be noticeably colder, especially coming off of 2 days of summerlike conditions. The MaxT24hrChange will be a setback of 10 to 15 degrees colder with highs a few to several degrees below average ranging from around 50F in the NW to mid 60s SE. A rather chilly Friday night with lows Saturday morning in the low 30s/40s to kick off the 5th month of the year. No freeze concerns at this time with 7 more zones activated in the growing season May 1. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... High confidence in cool and dry conditions Saturday, as upper trough lifts out and surface high builds into PA. Dry air at low levels will likely translate to afternoon minRH values around 30% or lower, although a subsidence inversion should prevent the mixing down of even drier air above the BL. All medium range guidance develops an upper ridge off of the east coast Sunday into early next week, with a quasi-stationary front draped across the Grt Lks into northern New England. A deep southwest flow should result in a return to above normal temperatures during this period, along with an increasing chance of showers, especially closer to the front over northwest PA. The latest ECENS and GEFS plumes indicate the best chance of showers will come in two bouts during the first half of next week. The first is likely Monday PM in association with a southern stream shortwave lifting out of the Miss Valley. The progged surface low track through the eastern Grt Lks favors northwest Pa for the most significant rain from this system. The second bout is likely to come Tuesday night or Wednesday associated with next wave of low pressure riding along quasi- stationary front. Current guidance suggest this system will track a bit further south, bringing a decent chance of rain across all of central Pa. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... For the 18Z TAFS, made some large changes. Unless things get active soon, backed off on the timing of the showers later this afternoon. A lot of cloud cover outside. Took thunder out of BFD. While there is a storm on the north side of Lake Erie at the current time, really hard to see much going on in our area given the time it would get into our area. BFD would have the best chance of a shower late afternoon, then perhaps JST later this evening. Thus backed off on lower CIGS later tonight. A weak low forecast to form on the cold front and lift northeast on Thursday. This system would likely in a higher chance of showers and storms later Thursday, with lower conditions. Outlook... Thu...Restrictions possible areawide in showers. Isolated thunder possible. Fri...Restrictions possible with rain showers. Gusty W/NW winds. Sat...MVFR cigs BFD/JST possible in morning. Breezy. Sun...Improving conditions. Mon...Mainly VFR conditions, but a chance of showers late NW. && .CLIMATE... Near-record high temperature (87F) at Harrisburg today. The record high is 90F set in 1957. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...DeVoir NEAR TERM...Fitzgerald SHORT TERM...DeVoir/Fitzgerald LONG TERM...Fitzgerald/Colbert AVIATION...Martin CLIMATE...
National Weather Service Hastings NE
622 PM CDT Wed Apr 28 2021 ...AVIATION UPDATE... .DISCUSSION...(This evening through Wednesday) Issued at 355 PM CDT Wed Apr 28 2021 Main concerns in the short term are potential for patchy frost tonight, then low-end near critical fire wx and temperatures Thu and into the weekend. Focus then turns to next chance for rain Sun into early next week. Water vapor shows a positively tilted trough stretching from the Upper MS Valley all the way into the Desert SW. The upper trough axis remains close enough to the area that we`re still seeing some iso shwrs/weak storms this aftn, mainly S of I-80 and E of Hwy 281. Not expecting much from this and what little PoPs we have will decr thru the eve. Skies are already beginning to clear out from N to S (a bit faster than expected), and this trend will continue thru the eve. Brzy N winds will also decr, but probably won`t go completely calm outside of low valleys and sheltered areas due to weak reinforcing front set to move in between 06Z and 12Z. Have low temps in the upper 30s from LXN to ODX, so could see some patchy frost for these areas. If winds end up lighter, could see slightly lower temps (more frost) given clr skies. Warming temp trend begins tmrw and continues thru weekend, and will come with some brzy conditions, at times. Some of the models suggest RHs could fall to near critical levels Thu and Fri aftn in the presence of 25 to 30 mph gusts Thu aftn, and 20-25mph Fri aftn. However, even the typically drier RAP model keeps us above 20 percent (critical) RH levels, so not overly concerned at this point, esp. considering fuels continue to become less and less favorable w/ time. Other than the brzy conditions, Thu and Fri look quite pleasant. Model consensus is for a series of shortwaves to dig thru the Great Lakes and carve out a deeper upper trough over the NE CONUS Thu night into Fri AM, but appears this will remain progressive and too far E to impact our wx. If anything, flow will take on an incr Wrly, downsloping component compared to Thu, and with good amnts of sunshine, should see nice jump in temps to upper 70s to mid 80s for Fri aftn. Temps jump even more for Sat as lee trough deepens and pulls low level thermal ridge squarely into the CWA. Incr pressure gradient force between departing high and new sfc low will lead to brzy and potentially windy conditions. Forecast high temps are already into the mid 80s to low 90s, and much like Mon, wouldn`t be surprised if this is too low and temps trend upward as we get closer. Dry atmosphere, SW low level flow, and strong insolation argue for this as well as potentially critical fire wx. Upper trough that cuts off over TX next 24hrs looks to eject NE Sun-Sun night, with next cold front entering the CWA Sun aftn-eve. GFS is more aggressive with QPF along the front relative to the EC. Like prev forecaster stated, can`t completely rule out some strong-svr storms along this front, but limited moisture (sfc Tds generally in the 50s), less than stellar lapse rates, and marginal shear argue against anything too significant attm. Best rn chances will be Sun eve into Mon, though official PoPs linger into Tue and even Wed. This could be overdone, esp if 12Z GFS/EC are onto anything. Nonetheless, temps will cool off to near normal levels for Mon-Tue. Temps look to rebound mid to late next week. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Friday) Issued at 617 PM CDT Wed Apr 28 2021 Expect a quiet night tonight overall with skies gradually clearing through the next several hours and early overnight. Cigs may continue to bound around slightly for the next hour or two between VFR and MVFR (the main reason being the extent of cloud cover, BKN vs SCT). Once things begin to clear up VFR conditions are expected through the end of the period. Also expect winds to quiet down to light and variable through the overnight. Winds are then expected to pick up again tomorrow out of the north and northwest by around mid-day. Gusts are expected to be generally in the 20-30kt range. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ DISCUSSION...Thies AVIATION...Shawkey
Area Forecast Discussion
National Weather Service Goodland KS
959 PM MDT Wed Apr 28 2021 .SHORT TERM...(This evening through Thursday night) Issued at 205 PM MDT Wed Apr 28 2021 Satellite imagery and 500 mb RAP analysis showed southwest flow over the region today, as an upper closed low spun over eastern Arizona and western New Mexico. An upper trough gradually pushed across the High Plains, keeping skies cloudy through the day with light precipitation grazing the northwestern and southeastern zones. At 2 PM MT, temperatures mainly ranged in the 50s. North winds were observed at 15 to 20 mph, with gusts around 30 mph. Temperatures fall into the mid 30s to low 40s tonight as northwest flow develops aloft behind the exiting trough. In the meantime, skies clear from the northwest and dry weather returns to the region. A warming trend begins on Thursday, when a broad ridge amplifies over the west coast. As a result, temperatures climb into the upper 60s to low 70s and dry conditions continue. North winds gusting up to 30mph can be expected across much of the area from the late morning through afternoon hours. Winds taper off and shift towards the south overnight as temperatures fall into the upper 30s/low 40s and the ridge noses into the Plains. .LONG TERM...(Thursday night through Wednesday) Issued at 244 PM MDT Wed Apr 28 2021 For this long-term forecast package, do expect a return to an active weather pattern with a variety of weather threats. At this time, nothing stands out as a more significant threat but that will need to be resolved for future forecast packages. Beginning with Friday and Saturday, southwest flow will return across the region as the upper level ridge begins to break down and a trough takes shape over the western United States. With the southwest surface flow, expecting dry weather conditions as well as a drastic warming trend. With those weather conditions, will need to think about fire weather threat. The high temperatures should be at least 10 to 15 degrees above normal, so low relative humidities seem quite reasonable with warm temps and dry air advection. Breezy conditions are also possible with a decent pressure gradient between surface high pressure to the east and developing low pressure along the Front Range. Thinking elevated to near critical fire weather conditions are likely on Friday along and south of I-70, and near critical to critical fire conditions Saturday from roughly Yuma to Goodland to Oakley. On Sunday, attention will turn to storm chances once again as several favorable ingredients for storms come together. First, a cold front will move south across the High Plains, ending somewhere across our forecast area during the daytime hours. In addition, a shortwave trough will move out over the Plains, providing that upper level trigger mechanism. Finally, warmth will still be in the area ahead of the front and this time, moisture return from the Gulf should have arrived to provide instability. Therefore, storms will be possible, especially along and east of Highway 25. It is still too early to resolve the details of timing, precise areas, and the particular severe-weather related threats, but wouldn`t be a surprise to have a few strong to severe storms at least in the vicinity. From Sunday night through Tuesday, active weather will persist in the form of continuing precipitation chances and cooler weather. Any severe weather threat should be gone with the front passing completely through the area by Sunday night. However, still could have some thunderstorms in the area. With cooler temperatures forecast, it`s not out of the realm of possibility that a few snowflakes may be observed somewhere Tuesday morning. However, was not confident enough in the temperature forecast to mention that in the forecast package at this time. For now, kept the precipitation as all liquid but if any flakes were to be observed, keep an eye on east Colorado. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 957 PM MDT Wed Apr 28 2021 VFR conditions forecast for the TAFs. Light winds tonight will become gusty close to 18z Thursday. The winds will decline toward 0z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...JBH LONG TERM...RRH AVIATION...JTL
Area Forecast Discussion
National Weather Service Phoenix AZ
527 PM MST Wed Apr 28 2021 .UPDATE... Updated Aviation section. && .SYNOPSIS... Today will bring some lingering showers and a few thunderstorms across the high terrain east of Phoenix and considerable warming to the lower deserts. A strong high pressure system will then take over late week resulting in much warmer temperatures and highs likely topping 100 degrees by Saturday. Temperatures will moderate somewhat early next week, but stay well above normal as dry conditions and mostly clear skies prevail. && .DISCUSSION... The upper level low continues to slowly shift southeastward through the region with the low center now just moving into extreme SE NM at this hour. Showers and a few TS continue to rotate southwestward around the low center across much of Gila County and into parts of extreme eastern Maricopa County. Although most places have seen little or no rainfall (so far), some spots across southern Gila Counties and extreme eastern Pinal Counties have seen measurable rainfall, with San Carlos RAWS measuring 0.40 inch between 1214 pm and 114 pm as a heavier shower moved across the region. Although drier air will gradually work in from the west through the remainder of the day/evening, there looks to be enough residual moisture across eastern Arizona to combine with daytime heating and steep lapse rates for additional convection. Hi-res models show convection attempting some westward propagation of the convection through the rest of the afternoon and into the early evening. However, HREF and HRRR guidance are still generally keeping the showers and thunderstorms across Gila County, but still can`t rule out a few inching into far eastern Maricopa and eastern Pinal Counties. A few hundred J/kg of CAPE and plenty of 0-6 km bulk shear may support a brief organized storm capable of small hail and sub-severe gusty winds across Gila County. A more likely impact to the lower deserts will be outflow winds from these showers/TS, with gusts as high as 25-30 mph possible. mainly across the far east and NE valley. Across the lower deserts today, significant warming is still forecast to occur as the impressive upper level ridge just off the West Coast nudges eastward into our region. However, the battle between the strong ridge to our west and the slow exit of the upper low will continue through the rest of the week. Model ensembles have continued to trend toward a slower exit of the upper low. This shift is expected to keep the highest heights from the ridge across central California northeastward into the Great Basin. Despite this subtle shift, very warm temperatures are still expected, but the likelihood of reaching 105 degrees across the Arizona deserts continues to drop. The latest forecast now calls for highs likely just topping 100 degrees across the western deserts on Friday with the Phoenix area into the upper 90s. Saturday still looks to be the hottest day with median NBM temperatures of 101-104 degrees across the western deserts to 99-102 for the Phoenix area. Daily record highs will still in jeopardy though, particularly Saturday with Phoenix`s probability of tying Saturday`s record of 103 now down to 28%, Yuma (106) at 10%, and El Centro (106) 26%. The hot temperatures Friday and into the weekend will begin to back off starting Sunday as an incoming trough into the Northwestern U.S. quickly dives southeastward into the Great Basin by Sunday afternoon. This will suppress heights aloft over our region, likely dropping highs back into the upper 90s for Sunday. Further cooling should be realized into early next week with Monday`s highs potentially into the lower 90s, or closer to normal readings. Eventually, the trough is likely to shift to the east with either zonal flow or slight ridging taking over across the Desert Southwest by the middle of next week. As a result, NBM guidance points toward warming temperatures again starting next Tuesday with more potential for 100 degree days at some point during the latter half of next week. && .AVIATION...Updated at 0027Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: A broad swath of easterly outflow winds (driven by evaporative cooling from weak showers originating over higher terrain) has exited the metro area. Significantly lighter easterly winds (gusts 15-25kts) will continue to weaken this evening but east and southeasterly directions are expected to continue the rest of the evening and overnight. One caveat is that there may be a period until about 03Z with variable directions as westerly winds in the lower levels above the surface mix with the remnants of the outflow. Virga showers will continue to dissipate as well with clear skies developing later this evening. Before then, SCT-BKN layers around FL100 can be expected with BKN layers roughly around FL150. The upper low that caused the shower activity and associated surface winds is centered near the New Mexico Bootheel and will sag southeastward tonight and Thursday. The strong northerly flow aloft (roughly AOA FL100) will trend to northeasterly. Winds below that level (but above the surface) will trend from westerly this evening to northerly overnight then easterly during the day Thursday. Southeast California/Southwest Arizona including KIPL and KBLH: An upper low centered near the New Mexico Bootheel is driving moderate to strong north and northeasterly flow at the surface and aloft. The low will sag southeastward tonight and Thursday. Northeasterly winds above the surface will continue tonight and through the day Thursday. Northerly breeziness at the surface will weaken this evening with light westerly directions developing at KIPL (favoring northerly at KBLH). Northerly surface winds will redevelop by late morning at KIPL. Northerly surface winds at KBLH will trend toward northeasterly Thursday afternoon. But, speeds Thursday will not be as strong as they were today. Otherwise, skies will be clear. && .FIRE WEATHER... Saturday through Wednesday: Strong high pressure will affect the region early in the period with near record heat likely for the upcoming weekend. High temperatures will climb each day through Saturday with 100-105 degrees possible before cooling slightly starting Sunday. A weather disturbance passing well to the north will bring even cooler temps for the early and middle part of next week, with lower desert highs falling into the low-mid 90`s by next Wednesday. Seasonably dry conditions are expected through the period with min RH values mostly in the mid single digit-low teen range. Winds will follow diurnal trends, but with somewhat elevated winds/fire danger levels on Sunday. && .CLIMATE... .Daily Record Highs... Phoenix Yuma El Centro .......... .......... ......... Fri 4/30 102 (1943) 103 (1943) 104 (1965) Sat 5/1 103 (1985) 106 (1947) 106 (1947) Sun 5/2 107 (1947) 111 (1947) 113 (1947) && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...Kuhlman/Percha AVIATION...AJ FIRE WEATHER...Kuhlman/Percha CLIMATE...Kuhlman
Area Forecast Discussion
National Weather Service Shreveport LA
1021 PM CDT Wed Apr 28 2021 .SHORT TERM.../Tonight/ The latest runs of the HRRR as well as the CAMs and 00Z NAm suggest that a line of more robust convection is expected to develop by/after 06Z Thursday over portions of extreme NE TX/SE OK/SW AR, near and ahead of a weak cold front that will advance SE into these areas, coinciding with a subtle upper level impulse ejecting NE in the SW flow. This is a little farther SE than what has been depicted over the last couple of days, with the 40-50kt Srly LLJ enhancing mid level convergence once the upper divergence increases late ahead of the closed low sags SSE into Nrn old MX from Srn NM. These progs suggest that QPF`s of 2-4 inches are possible, with isolated higher amounts of 5-6+ inches depicted by the HRRR and CAMs over portions of extreme NE TX (from Red River and Northwest Bowie Counties) into portions of extreme SW AR. Given PW`s in excess of 1.8 inches (on the higher end of climatology), and the extent of forcing late, have expanded the Flash Flood Watch to include Bowie, Little River, Sevier, and Howard Counties, while also extending the duration of the Watch through 21Z as the convection and potential flooding may extend a little later into the afternoon over these areas. Any svr threat looks as if it will wait until after midnight when the deeper convective line develops, although it will encounter weakening CAPE as it moves into the region. Otherwise, did make some minor adjustments to pops, mainly to trim back the Srn extent over E TX/NW LA/SCntrl AR, while also raising min temps a bit over Lower E TX/N LA which should remain rain- free, and be influenced with the low clouds/wind, thus resulting in warmer readings. Zone update already out...grids will be available shortly. 15 && .PREV DISCUSSION... /issued 811 PM CDT Wed Apr 28 2021/ UPDATE... Zone update just sent for the issuance of TOR Watch #121 in effect until 07Z Thursday for a small portion of extreme NE TX/SE OK/adjacent sections of SW AR. A gradual uptick in convection has been observed over the last hour over portions of NE TX/SE OK, with the latest HRRR as well as the global models suggesting convection deepening late this evening ahead of a weak cold front over Cntrl/NE OK, which will slide SE thus resulting in the convection slowly building SE into these areas late. Did add severe and heavy rainfall mention for these areas, which coincides with the Flash Flood Watch already in effect. 15 && PREV DISCUSSION... /issued 648 PM CDT Wed Apr 28 2021/ AVIATION... VFR conditions will continue for much of this evening, although MVFR cigs are expected to develop after 02-04Z across portions of E TX/N LA, and spread N across the remainder of the region after 06Z Thursday. Meanwhile, convection is expected to increase later this evening across portions of extreme NE TX/SE OK and adjacent sections of Wrn AR, before gradually sliding SE overnight. This convection may come as close as the TYR/TXK terminals by 08-10Z, where VCTS was maintained, although tempo thunder mention may be needed in later TAFs with reductions to cigs/vsbys. This convection should persist over these same areas through much of the morning, before weakening by mid to late morning. However, additional redevelopment is expected through Thursday afternoon near and ahead of a weak cold front that will drift SSE into extreme NE TX/SW AR. While this convection will likely maintain MVFR cigs through much of the day, the lower cigs should eventually lift/become VFR by late morning/midday elsewhere across Lower E TX/N LA, although some reductions to cigs/vsbys are possible in the afternoon in and near the redeveloping convection along the front. SSE winds 8-13kts tonight through much of Thursday will eventually become N 5-9kts with the fropa over SW AR/E TX and NW LA along/N of I-20. /15/ && .PRELIMINARY POINT TEMPS/POPS... SHV 72 84 64 77 / 20 60 60 40 MLU 70 86 65 75 / 0 40 70 40 DEQ 68 77 59 77 / 90 90 40 20 TXK 71 78 62 75 / 60 80 60 30 ELD 69 81 61 75 / 20 60 60 30 TYR 70 79 64 75 / 60 80 60 30 GGG 70 80 64 75 / 40 70 70 40 LFK 71 85 68 76 / 10 60 50 40 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...Flash Flood Watch through Thursday afternoon for ARZ050-051-059. LA...None. OK...Flash Flood Watch through Thursday afternoon for OKZ077. TX...Flash Flood Watch through Thursday afternoon for TXZ096-097-108- 109. && $$ 15