####018010942#### FXUS64 KMAF 030830 AFDMAF Area Forecast Discussion National Weather Service Midland/Odessa TX 330 AM CDT Fri May 3 2024 ...New SHORT TERM, LONG TERM, FIRE WEATHER... .SHORT TERM... (Today through Saturday afternoon) Issued at 311 AM CDT Fri May 3 2024 An active period is ahead for the short term, with severe thunderstorms possible both today and Saturday. Early this morning, winds are generally light and variable, thanks to a combination of a weak cold front sagging across the Permian Basin and the retreating dryline. Dewpoints across the Permian Basin and into Lea County have recovered into the 50s and even lower 60s, with lows not expected to drop much below where they area now, in the upper 50s to upper 60s for many. Expansive low clouds have already worked their way northwestward into portions of the Lower Trans Pecos, and are progged to expand across the central and eastern Permian Basin through daybreak. However, clearing skies are expected by mid-morning, allowing for plenty of time for warming and subsequent destabilization ahead of convective development this afternoon. As southwesterly winds develop this afternoon, the dryline will mix eastward from its morning position west of the Pecos River, and sharpen up from the Permian Basin southward across the Trans Pecos to the Rio Grande. The aforementioned cold front this morning will wash out, mixing northward this afternoon as southerly flow increases across the eastern half of the forecast area. Highs today top out in the middle 80s to lower 90s for most, with 100s along the Rio Grande in the Big Bend. Given elevated moisture to the east of the dryline, diurnal destabilization will result in CAPE values in excess of 2500-3000 J/kg (and possibly up to nearly 4000 J/kg). Lapse rates around 8 degC/km will support large to very large hail, with veering flow and increasing low- level shear through the late afternoon and early evening lending to a non-zero tornado threat. Initiation is progged to occur over the Permian Basin and Trans Pecos south toward the Rio Grande by mid-afternoon, with storms generally moving eastward and gradually congealing into outflow-dominated clusters by the evening. A bulk of the activity should be east of our area by mid-evening, though a few lingering non-severe storms may be possible over northern portions of the area overnight as the dryline retreats, in closer proximity to the diffuse frontal boundary. The low-level jet will keep winds and moisture elevated tonight, allowing the dryline to once again retreat to the higher terrain of Southeast New Mexico and Southwest Texas. In a change from today, convective initiation is expected earlier in the day on Saturday as the aforementioned front surges southward coincident with a surface trough that develops immediately to the lee of the higher terrain. Thus, precipitation chances as well as potential for strong to severe storms encompass much of the area, with particular focus across the Permian Basin and Trans Pecos where the greatest potential (40%-70%) for severe storms exists along the eastward moving dryline and southward moving cold front. Shear will be notably stronger on Saturday, around 35-45kt, and moderate to strong instability will yield mainly an initial supercellular storm mode, with very large hail and damaging winds the primary concerns, along with locally heavy rainfall given precipitable water values increasing to 1 to 2 standard deviations above normal by late afternoon and early evening, per NAEFS ensemble data. Storms are progged to linger into the evening, and aside from the storm potential, the cold front will also yield cooler temperatures, with afternoon highs in the 80s to lower 90s along and south/west of the Pecos (hotter along the Rio Grande), with 70s encroaching over the northern tier of the forecast area where the front will arrive prior to peak heating. JP && .LONG TERM... (Saturday night through Thursday) Issued at 311 AM CDT Fri May 3 2024 Rain chances will continue Saturday evening into Sunday afternoon before tapering off as the southern stream short wave trough and upper low move east of the area by then. Potential for strong to severe storms continues Saturday night for eastern portions of the area, with the threat for flooding rains, damaging winds, and large hail. Widespread clouds and rain chances Saturday night will keep lows mild and slightly above normal in the 60s for most aside from 50s in higher elevations and northern portions of the SE NM plains. Highest rainfall amounts are likely east of the Pecos River, especially east of the Midland-Odessa area over the eastern Permian Basin and Western Low Rolling Plains, where maximum rainfall totals at the end of this rain event are forecast to range from 1.00 to 2.00 inches. As the upper low responsible for this weekend's rain moves east and takes on a negative tilt as it moves into the central Great Plains, increasing quasi-zonal flow will push the dryline that has been present over much of the central Permian Basin the past few days well to the east of the area. Accompanying this dryline passage beginning Monday afternoon will be increasing southwesterly winds, clearer skies, and a warming trend Monday into Thursday as subtle mid-level ridging also builds in. No rain is expected for the rest of the long term until at least Friday. A cold front will move in from the north Thursday, with cooler temperatures expected to close out next week. Highs will be below normal Sunday due to lingering cloud and rain chances, with widespread low to mid 80s and 90s confined to parts of the Trans Pecos and Rio Grande valleys. Monday through Thursday will see highs above normal with widespread upper 80s and 90s, and reaching triple digit readings near the Rio Grande. Highs Friday will be near to below average following the passage of a cold front, with mainly 80s and higher readings in the 90s confined to the Trans Pecos, Terrell County, and along the Rio Grande in the valleys. Lows will be above normal for early May throughout the long term with widespread 60s, aside from 50s in higher elevations and northern portions of the SE NM plains and Permian Basin, each night from Saturday night into Thursday night. Lows Friday night will be closer to normal and feature 50s for most places north and east of the Pecos River, most of the SE NM plains and higher elevations across West Texas, and 60s elsewhere. && .AVIATION... (06Z TAFS) Issued at 1218 AM CDT Fri May 3 2024 A weak cold front is sagging southward into the area, while the dryline is starting to retreat westward, resulting in some fairly variable winds. Sustained speeds tonight are expected to remain under 12kt, with winds expected to settle out of the E/SE by morning. Winds will shift to the S/SE, becoming gusty during the afternoon, with gusts sticking around into the evening for MAF/INK/FST where the low-level jet will come into play. MVFR ceilings are progged to develop into the area late tonight, though have only included mention at MAF where confidence is highest. VFR conditions will return to MAF by around 14Z, with VFR conditions otherwise prevailing. Thunderstorms are possible, mainly during the 21Z-02Z time frame for MAF/FST, but will defer to later issuances for potential TS mention. && .FIRE WEATHER... Issued at 311 AM CDT Fri May 3 2024 ERCs 90th percentile or higher over most of Eddy County and southwest of the Pecos River will result in critically dry fuels fuels. This afternoon, RFTIs of 3-5 present from Sacramento Foothills into Chaves, Eddy, and Lea Counties in Southeast New Mexico into the Guadalupe Mountains and eastern Culberson County, along with min RH from 6 to 10 percent and highs 5 to 8 degrees above normal for this time of year in the upper 80s and lower 90s, have prompted a Rangeland Fire Danger Statement to be issued for these regions from this afternoon through this evening. Rain east of the Pecos River and lack of gusty winds likely constrain fire weather risk Saturday into Sunday. However, fire weather risk increases again Monday afternoon and continues into next Thursday as near zero rain chances are present for much of the area, dewpoints decrease over much of the area, widespread min critical RH develops each afternoon Monday into Thursday, and gusty southwesterly winds develop over much of the SE NM plains into the mountains and western Permian Basin in West Texas each afternoon from Monday into Thursday. This will all contribute to widespread RFTIs in the 3-6 range west and southwest of the Pecos River Monday, Tuesday, Wednesday, and Thursday afternoons. In addition to all of this, highs and lows 5 to 10 degrees above normal and mainly in the 90s and 60s, respectively, as well as poor overnight recovery over much of the area from Monday into Thursday morning, will dry out fuels even more. Depending on extent and amount of rainfall Friday into Sunday, eastward extent of fire weather risk is still uncertain at this time. Still, near critical fire weather conditions are likely Friday and this weekend over southwesternmost Eddy County and West Texas, and critical fire weather conditions Monday into Thursday next week expected over the SE NM plains, much of the area southwest of the Pecos River and west of a line from Gaines County into central Pecos County into western Terrell County, each afternoon from Monday into Thursday. Behind a cold front moving in from the north at the end of next week, increased dewpoints, better overnight recovery Friday morning, and decreasing eastward extent of min critical RH all yield a decrease in fire risk for the end of next week. && .PRELIMINARY POINT TEMPS/POPS... Big Spring 88 63 79 60 / 40 40 80 80 Carlsbad 92 60 84 58 / 0 10 20 40 Dryden 92 68 85 67 / 20 10 30 40 Fort Stockton 92 66 89 63 / 30 20 50 50 Guadalupe Pass 83 59 79 57 / 0 0 10 20 Hobbs 89 59 79 56 / 10 10 50 60 Marfa 87 54 89 52 / 10 0 20 30 Midland Intl Airport 90 63 81 60 / 30 30 60 70 Odessa 90 64 82 62 / 30 30 60 70 Wink 93 66 87 62 / 10 10 40 60 && .MAF WATCHES/WARNINGS/ADVISORIES... TX...None. NM...None. && $$ SHORT TERM...84 LONG TERM....94 AVIATION...84 ####018006570#### FXUS63 KBIS 030833 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 333 AM CDT Fri May 3 2024 .KEY MESSAGES... - Expect low to medium chances (20 to 60 percent) for rain showers through the day, mainly across the northern half of western and central North Dakota. Some light snow may mix in across the west this morning. - Temperatures will warm through the weekend, with windy conditions on Sunday. - Chances for rain return Sunday evening and continue through the work week. The wettest period will Monday through Tuesday when most of western and central North Dakota will see medium to high chances (60 to 90 percent) of rain. && .DISCUSSION... Issued at 333 AM CDT Fri May 3 2024 Early this morning, western and central North Dakota sits under the influence of broad quasi-stationary troughing overhead. The upper low that brought showers and thunderstorms to the region yesterday will continue to eject out into Ontario to our northeast as the next upper low rotates down into northwest North Dakota from southern Saskatchewan later today. This low will be the trigger for showers to develop through the day (20 to 60 percent chance), mainly across the northern half of the forecast area (best chances along the International Border). Some light snow may even mix in across the west briefly this morning. RAP soundings suggest that instability will be limited this afternoon and evening with MUCAPE values mainly maxing out in the 100 to 200 J/kg range. While a stray rumble of thunder or two cannot be ruled out, confidence is not high enough to include mention of thunder in the gridded forecast at this time. Precipitation chances will diminish to the northeast tonight as the upper level trough finally starts to move out to our east, transitioning western and central North Dakota into northwest flow aloft on Saturday. Surface high pressure will also slide in on Saturday, leading to diminishing clouds from west to east and slightly warmer temperatures. Highs will remain cool today, ranging from the mid 40s northeast to the mid 50s southeast and then by Saturday, highs will range from the lower 50s to lower 60s. An upper level ridge axis then approaches Saturday night and crosses the state on Sunday. This will mean even warmer temperatures with forecast highs ranging from the lower 60s to lower 70s. Behind the ridge axis, a deep trough will approach from the west, transitioning western and central North Dakota into meridional flow aloft. As this trough approaches, a surface low will deepen to around 990 mb or less over eastern Montana. This will lead to strong warm air advection, pressure falls, and a rapidly tightening pressure gradient on Sunday for our area. So, while highs will be fairly mild, it will be windy with soundings suggesting the potential for 40 knots or so available to mix down from the top of the mixed layer. The potential for gusts up to 45 mph seems reasonable for now and an eventual Wind Advisory seems like a decent probability. The story then turns to the approaching strong storm system and widespread rain event Sunday night through the week. The sub 990 mb surface low will continue to deepen as the upper level trough starts to take on a negative tilt and nudges into the northern Plains. Widespread showers and some thunderstorms will develop through the day and night, but dry slotting is likely to setup somewhere depending on the eventual track of the low. While thunderstorm chances will be better than in previous days, instability still appears to be somewhat lacking. However we could see some MLCAPE values up to 500 J/kg with deep layer shear forecast to range from around 35 to 45 knots. So, the severe weather potential appears to be fairly low but a couple of strong storms may be on the table. The wettest period will generally be Monday through Tuesday (widespread 60 to 90 percent chances for showers) and another potential hazard could be heavy rain, especially if heavier showers/storms can train over some of the same areas. NBM 72-hour probabilities (ending 12z Thursday) don't suggest anything too dramatic with most of the west and central in medium probabilities (40 to 70 percent) for an inch of rain or more (the one exception being the James River Valley where the consensus currently wants to place most of the dry slotting). When we increase that threshold to two inches, the probabilities fall off mainly into the 10 to 30 percent range. However, it is worth noting that the NAEFS is showing Integrated Water Vapor Transport, PWATs, and 850 mb specific humidity in the 97.5th percentile or greater for this time of year in the Monday through Tuesday time frame. Thus, there may be an opportunity here for some heavier rainfall in a few locations. The upper low will start to wind down by mid week but will be slow to kick out into the Great Lakes region given a stubborn east coast ridge. Low to medium chances (20 to 60 percent) for showers will continue through at least Thursday. Highs on Monday will not be quite as warm as Sunday given widespread clouds and rain. However, we should still see highs in the 60s. With the cool wet pattern continuing, highs will mainly dip back into the lower 50s to lower 60s for most of the rest of the work week. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 117 AM CDT Fri May 3 2024 The next chance of rain will start to enter the northwest in the next few hours, potentially impacting KXWA. More showers will develop throughout the day on Friday but will generally be of the hit and miss variety. With such uncertainty about eventual location and tracks of these showers, we elected to keep mention of rain out of any specific site forecast except for KXWA where confidence is a bit higher. There is a small chance for a rumble of thunder or two as well. IFR to MVFR ceilings will be likely across the west and north through much of the period, including KXWA, KDIK, and KMOT. For now, it appears that KBIS and KJMS should remain in VFR categories through the period. Winds will become a bit gusty out of the west Friday afternoon, when we could see some gusts up to 35 mph. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...ZH AVIATION...ZH ####018004271#### FXUS63 KARX 030834 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 334 AM CDT Fri May 3 2024 .KEY MESSAGES... - Areas of fog this morning. This fog may be localized dense. As drier air moves into the region and diurnal mixing occurs, this fog should burn off rapidly between 8 and 10 AM. - Rain and scattered storms are expected late tonight and Saturday. This rain will likely only last up to 6 hours in any location. With better forcing and moisture transport into the region, rainfall amounts were increased. They now look to range from a tenth to a half-inch. Highest rain totals look to be west of the Mississippi River where the forcing and moisture transport is the best. - For early next week (Tuesday and Tuesday night), there appears to be risk of severe weather. While the shear looks good, still some uncertainty of the amount of instability. && .DISCUSSION... Issued at 334 AM CDT Fri May 3 2024 This Morning - Areas of fog - potentially dense The combination of clearing skies, light winds, and recent rainfall will result in the development of fog across much of the area early this morning. There may be even some localized dense fog. As drier air moves into the region and diurnal mixing develops this fog should quickly dissipate between 03.13z and 03.15z. Late Tonight through Saturday - Rain and scattered storms The 05.03z models are in good agreement that a longwave trough will move east through the forecast area from late tonight into Saturday. Ahead of this wave, a 40 to 50-knot 850 mb jet will increase the moisture transport across the area. Precipitable water values will increase into the 1 to 1.4 inch range. The highest values will be south of Interstate 90. This is higher than the past couple of days. Due to this the precipitation totals were increased. They now range from a tenth of an inch to a half-inch. The highest values will be likely west of the Mississippi River where the forcing and moisture transport will be the strongest. The CAMs show that the rain and scattered storms will likely only affect an area up to 6 hours. Used the CONSShort and the CAMs to try and add some timing to this precipitation. Even by doing this, still likely holding onto this precipitation a bit too long. While the 0-6 km shear increases into the 40 to 50 knot range (highest north of Interstate 90), the 0-4 km most-unstable CAPES remains below 100 J/kg, so not anticipating any severe weather from these storms. Monday Night into Tuesday Night - Another round of showers and storms The models continue to show that a closed 500 mb low will lift out of the desert southwest and move into the Northern Plains on Monday. A negatively-tilted shortwave trough will move northeast through the area on Tuesday. This will likely result in a line of showers and storms. Both the deterministic GFS and ECMWF suggest the potential for the 0-6 km shear will be in the excess of 40 knots. The main question continues to be the timing differences with this system which greatly impacts the amount of instability that will be found across the region. Colorado State severe probability still shows a 15 to 30% chance in northeast Iowa and southwest and central Wisconsin. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 958 PM CDT Thu May 2 2024 With increasing probabilities of IFR fog over northeast Iowa, it appears the Miss river valley could also see some MVFR fog by morning as well. Through the past several hours, most of the probabilities in the NBM guidance are consistent with some fog at KLSE. Have decided to add MVFR fog as a trend. With winds above the boundary layer at inversion height still 20 kts, think the valley fog scenario is unlikely. It would be more of a synoptic fog with possibly a slight preference for the valleys to have lower visibility with cool air drainage under the surface ridge axis. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Boyne AVIATION...Baumgardt