####018005691#### FXUS62 KMHX 030530 AFDMHX Area Forecast Discussion National Weather Service Newport/Morehead City NC 130 AM EDT Fri May 3 2024 .SYNOPSIS... High pressure builds in for a couple of days before yet another cold front impacts the area over the weekend bringing slight chances for showers, but should remain mainly west of ENC. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... As of 935 PM Thu... Not much has changed since the previous update as latest obs show clear skies and light winds across ENC this evening. Expect over the next few hours for patchy fog to develop especially around the Crystal Coast and lift N'wards overnight. The only caveat to this is if a weak gradient can maintain itself overnight there would be a very low chance we remain fog free tonight across ENC. However given the continued support from the Hi-res guidance, clear skies, and already light winds have kept fog in the forecast across the region with the potential for dense fog across the southern half of the CWA still in play. High res model suite and HREF probs are highlighting a 60-80% chance for less than 1 mile visibilities in this area with closer to 10-30% probs from about Lenoir, Northern Craven, and Beaufort counties north and the fog forecast reflects this. May need a headline DFA at some point tonight depending on how fog covg and density evolves. Winds will be calm to light ssw overnight. Otherwise lows get down into the low 60s across the region tonight. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/... As of 303 PM Thu...After morning fog burns off, another very warm day on tap, with highs into the mid and upr 80s interior, to 70s coast as a dry sea breeze develops once again. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... As of 0330 Thursday...Quiet until this weekend when conditions become more unsettled through early next week. Best rain chances on Sunday Weekend...The mid-level ridge remains over the eastern US Saturday but weakens as a complex series of shortwave troughs and surface lows move toward the area, resulting in unsettled conditions that will persist into the beginning of next week. Chances for showers and storms start to increase Saturday morning and peak Sunday (30-50%). Shower and storm chances hang around through the period due to the lingering nature the front, but they will be decreasing as we progress into next week (25-50% Monday, 15-30% Tuesday). Saturday's high temps will be a few degrees cooler than Friday due to the originally dry cold front that will dip south (low 80s coastal plain, low 70s beaches). Temps remain around the same Sunday. Early next Week...Upper ridging builds back over the area Tuesday behind a weak shortwave passing Monday. Shortwave and remnants of the weekend's front/SFC trough will lead to some precip Mon. Temps rebound next week with highs expected to reach back into 80s Mon and Tues, 90s Wed. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... SHORT TERM /through Fri/... As of 0115 Friday...VFR flight cats make way to subVFR with fog expected to develop overnight. Best chance for coastal TAF sites with inland sites being more uncertain. Fog could become dense at times especially along the Crystal Coast which would result in IFR/LIFR conditions at the EWN/OAJ TAF sites. Inland TAF sites will possibly see MVFR VIS conditions and considering how often PGV reports IFR/LIFR VIS for less than impactful fog, have added TEMPO IFR groups for ISO and PGV. VFR returns after fog dissipates a few hrs after sunrise. LONG TERM /Sat through Tuesday/... As of 0330 Thursday...Pred VFR expected through Friday. Conditions become more unsettled this weekend through early next week due to a series of disturbances moving across the area. There will be multiple chances for showers and storms with Sunday having the greatest threat (30-60%). Periods of lower CIGs and VIS as well as gusty winds if near any storms can be expected. && .MARINE... SHORT TERM /through Fri/... As of 303 PM Thursday...Sub-SCA conditions through the period. Winds will be light (5 kt or less) and variable for much of the day but will slightly increase in speed (5-10 kt) as they transition to southerly and then eventually southwesterly by later tonight. Seas only 1-2 ft throughout. May be dense fog again for coastal waters, sounds, and rivers once again, esp further south in the srn/ctrl coastal waters, Pamlico Sound, and Neuse/Pamlico rivers later this evening into early Fri. LONG TERM /Sat through Tuesday/... As of 0330 Thursday...Sub- SCA conditions are expected through the period but multiple chances for showers and thunderstorms could create hazardous boating conditions. Sunday presents the best opportunity for showers and storms (30-40%). Winds veer to the southwest by early Friday. A dry cold front will sag south into northern counties on Friday. North of Cape Hatteras, 5-10 kt winds will be out of the E by the afternoon. South of Cape Hatteras, winds will be 5-10 kt out of the ESE. Winds and seas pick up Saturday- Sunday as a front approaches. Winds will be ESE around 10-15 kt Saturday and then southerly by Sunday. Seas remain around 2 ft until Saturday when they will increase to 2-4 ft. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...None. && $$ SYNOPSIS...MHX NEAR TERM...TL/RCF SHORT TERM...TL/OJC LONG TERM...JME/CEB AVIATION...CEB MARINE...TL/CEB ####018006672#### FXUS63 KLSX 030531 AFDLSX Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 1231 AM CDT Fri May 3 2024 .UPDATE... Issued at 742 PM CDT Thu May 2 2024 Increased PoPs to categorical tonight as nearly the entire CWA is covered by showers and thunderstorms ahead of a slow moving cold front. Threat of severe weather is over. CVKING && .KEY MESSAGES... - Showers and thunderstorms will continue through the afternoon and evening. There is potential for an isolated severe thunderstorm across central through northeast Missouri and west- central Illinois between 2-8pm. Should a thunderstorm become severe, the hazards will be damaging winds up to 60 mph and quarter sized hail. - An active weather pattern will continue through at least mid- week, with strong to severe thunderstorms possible at points between Saturday and next Wednesday. && .SHORT TERM... (Through Late Friday Night) Issued at 239 PM CDT Thu May 2 2024 Radar imagery is showing two areas of shower and thunderstorm activity, one across southwest Missouri and another ahead of a cold front extending from west-central Missouri through northeast Missouri. Current water vapor imagery and surface analysis shows the Mid-Mississippi River Valley in deep southwesterly flow. Amidst southwesterly flow is a shortwave trough that is pushing its way into southwest Missouri and is the current focus of the convection in that area. Ahead of this shortwave, from central Missouri through northeast Missouri, is a region of vorticity advection. With increased deep moisture convergence and ample mid- day heating due to a decrease in cloud cover this morning, these areas are the prime location for shower and thunderstorm development and intensification over the next few hours. It is possible that a few of these thunderstorms could become strong to severe with the primary threat being damaging winds however quarter sized hail cannot be ruled out. 18Z environmental analysis indicates SBCAPE values between 1500-2000 J/kg and deep-layer shear values maximized between 20-25 kts across the aforementioned areas. This low shear environment will help keep thunderstorms disorganized and further limit the severe chances. The most likely time for isolated severe thunderstorms will be between 2 - 8 pm. The strong to severe thunderstorm potential will diminish quickly after sunset with the loss of instability and weaker shear further to the east. These showers and thunderstorms will continue to move east-northeast through the afternoon and evening hours as the shortwave treks to the northeast and the cold front shifts east. Showers with a few rumbles of thunder are expected overnight and will diminish on Friday. Despite the passage of the cold front and northeasterly flow, high temperatures on Friday will remain near to slightly above normal for early May. MMG/Jaja && .LONG TERM... (Saturday through Next Thursday) Issued at 239 PM CDT Thu May 2 2024 Our ongoing active pattern will continue this weekend and into the middle of next week as multiple shortwaves pass through the Mid- Mississippi Valley. The first of these shortwaves will arrive Saturday afternoon into evening, bringing with it the potential for strong to severe thunderstorms. At the surface, a cold front will be approaching the region from the northwest with abundant moisture return ahead of it. Deterministic guidance is quite uniform in depicting mid-60s dewpoints across most of the CWA on Saturday, with 70-90% of ensembles corroborating this. If this comes to fruition, dewpoints on Saturday will be above the 90th percentile of climatology and jeopardizing records at KSTL/KCOU/KUIN. Despite anomalous moisture, there is uncertainty regarding the amount of instability we'll have on Saturday. Ensembles range from 500-1000 J/kg, but incoming cloud cover, warmer or cooler temperatures, and timing of the frontal passage could all sway these values higher or lower. With upper level ascent, abundant moisture and instability, and a surface trigger all present, confidence is high that we will see convection on Saturday. What's uncertain is the strength of thunderstorms that do develop. Another shortwave is forecast to pass over the region sometime Sunday into Monday as a surface low and warm front push north through the CWA. This will bring more precipitation to the area, but the potential for severe will be much lower than on Saturday. Anomalous moisture and heat will be wiped clean from the area by Saturday's cold front and deep layer shear will be unimpressive. Anything that initiates along the warm front would be elevated in nature and quite shallow according to model soundings. With guidance trending later into the evening on the arrival of the shortwave, this only dampens the potential for severe. A deep mid-level trough will swing through the Intermountain West and into the Plains early next week. This feature will be the point of focus for severe weather next week as it enhances upper level ascent and deep layer shear, and at the surface advects warmer air and more abundant moisture back into the Plains and Midwest, increasing instability. There are still too many differences among guidance (as highlighted in very different WPC clusters for next week) to discuss specifics, but this is a set-up conducive for severe weather. Just when and where that happens is unclear as of yet. Jaja && .AVIATION... (For the 06z TAFs through 06z Friday Night) Issued at 1221 AM CDT Fri May 3 2024 Showers along and ahead of a cold front are gradually winding down across the area, with impacts from rainfall departing the terminals through the early morning hours. The front will slowly sag across the local terminals, leading to a period of variable winds until the front clears the sites with winds becoming northerly to northeasterly in its wake. Additionally, a relatively narrow band of low stratus is expected along the front brining MVFR to IFR ceilings to the area. Given the slow moving nature of the front and it pivoting across the region as it moves through, low stratus may hang around KCOU, KJEF, KSUS, KSTL, and KCPS longer than indicated into the mid to late morning. Elmore && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX ####018006034#### FXUS64 KEPZ 030532 AFDEPZ Area Forecast Discussion National Weather Service El Paso Tx/Santa Teresa NM 1132 PM MDT Thu May 2 2024 ...New AVIATION... .SYNOPSIS... Issued at 130 PM MDT Thu May 2 2024 Very warm temperatures with breezy winds are expected to continue into the weekend. A storm system will pass north of the region on Sunday which will increase wind speeds and fire weather concerns. The region will remain very dry so no rainfall is expected to accompany this system. && .DISCUSSION... Issued at 130 PM MDT Thu May 2 2024 Currently, zonal flow is taking place aloft, which is allowing for very dry, warm, and breezy conditions to predominate. Ridging will build in on Friday which will reinforce the aforementioned conditions. The dry line is east of our region and will remain just out of reach for the rest of the forecast period. A couple of small shortwaves will pass through the region over the next few days but will allow for a few clouds at best and mostly in higher elevations. Mainly southwesterly to westerly flow at the surface will continue for the rest of the forecast period. This will allow for continued warm air advection which will keep temperatures in the upper 80s and lower 90s. An upper level trough will pass north of the region on Sunday and into Monday. No rain chances are expected with this event. This will trigger lee cyclogenesis over the Rocky Mountains. However, the surface low that results will be over the northeastern region of Colorado, which is not as favorable for winds. Our wind speeds will still increase (20-25 mph with gusts of 30-35 mph) due to tighter pressure gradients, but won't be high enough for any wind products. The south and southeastern regions will have lighter winds due to the 700mb jet being situated to our northwest. These wind speeds combined with the very dry and warm weather will allow for critical fire weather conditions on Monday and Sunday, which is the largest concern for this period. Into next week, a second bout of lee cyclogenesis will result in a weak surface low over southeastern Colorado. This will keep winds breezy (15-20 mph) for the first half of next week. && .AVIATION... (06Z TAFS) Issued at 1131 PM MDT Thu May 2 2024 VFR conditions persist through the forecast period. Other than FEW250 from time to time, SKC expected. W winds AOB 8kts expected through the AM. Gusts return for all TAF sites for the afternoon near 20kts from the SW before subsiding late in the period. && .FIRE WEATHER... Issued at 130 PM MDT Thu May 2 2024 Elevated fire weather concerns for the rest of the week. RH values will be very low at between 5-10% for the lowlands and 10-15% for higher elevations for the entire period due to continued southwesterly to westerly flow. High temperatures will be very warm in the low 90s and upper 80s for the whole period. Wind speeds will be breezy (10-15mph) for the rest of the week. On Sunday and into Monday, a Pacific storm system will pass north of the region which will allow for a low pressure system to develop over northeastern Colorado. This will increase wind speeds to around 20-25 mph with gusts of up to 30-35 mph with the southern regions having lighter winds. Fire weather concerns will become critical for Sunday and Monday as a result. No rain chances are expected with this storm system. The next half of next week will have breezy winds due to a weak low pressure system over southeastern Colorado that will influence the region. Ventilation rates will be excellent for the entire period. && .PRELIMINARY POINT TEMPS/POPS... El Paso 60 89 62 90 / 0 0 0 0 Sierra Blanca 55 84 56 86 / 0 0 0 10 Las Cruces 54 88 55 89 / 0 0 0 0 Alamogordo 52 86 54 88 / 0 0 0 0 Cloudcroft 41 63 41 64 / 0 0 0 10 Truth or Consequences 54 85 54 86 / 0 0 0 0 Silver City 48 76 49 77 / 0 0 0 0 Deming 49 86 50 87 / 0 0 0 0 Lordsburg 49 84 49 84 / 0 0 0 0 West El Paso Metro 57 86 59 88 / 0 0 0 0 Dell City 48 89 51 90 / 0 0 0 10 Fort Hancock 52 90 54 93 / 0 0 0 0 Loma Linda 53 81 55 82 / 0 0 0 0 Fabens 56 89 55 91 / 0 0 0 0 Santa Teresa 52 84 53 87 / 0 0 0 0 White Sands HQ 60 86 60 87 / 0 0 0 0 Jornada Range 50 85 51 86 / 0 0 0 0 Hatch 49 87 49 88 / 0 0 0 0 Columbus 55 85 54 87 / 0 0 0 0 Orogrande 52 84 54 85 / 0 0 0 0 Mayhill 46 76 45 76 / 0 0 0 10 Mescalero 44 74 44 75 / 0 0 0 10 Timberon 42 73 44 75 / 0 0 0 10 Winston 46 78 46 78 / 0 0 0 0 Hillsboro 49 83 50 83 / 0 0 0 0 Spaceport 49 84 49 85 / 0 0 0 0 Lake Roberts 43 77 44 78 / 0 0 0 0 Hurley 45 80 45 81 / 0 0 0 0 Cliff 48 83 49 84 / 0 0 0 0 Mule Creek 49 78 49 79 / 0 0 0 0 Faywood 49 79 49 80 / 0 0 0 0 Animas 49 84 49 84 / 0 0 0 0 Hachita 50 84 50 84 / 0 0 0 0 Antelope Wells 49 84 49 85 / 0 0 0 0 Cloverdale 49 77 49 78 / 0 0 0 0 && .EPZ WATCHES/WARNINGS/ADVISORIES... TX...None. NM...None. && $$ FORECASTER...17-Hefner ####018004075#### FXUS64 KHUN 030533 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 1233 AM CDT Fri May 3 2024 ...New AVIATION... .NEAR TERM... (Rest of tonight) Issued at 914 PM CDT Thu May 2 2024 A weak cold front will continue to approach the Tennessee Valley overnight in response to a mid/upper low shifting into the Great Lakes. With high pressure shifting east of the area, southerly flow has helped to advect in Gulf moisture as seen by the mid 60s dewpoints in the latest 02z observations. Ahead of this front, sufficient forcing and deeper moisture will allow for low to medium (30-60%) chances for showers and a few elevated thunderstorms to develop, especially after 06z. More widespread and higher chances (60-80%) for showers/storms are forecast during the day on Friday as the front slowly moves in (more on this in the section below). For the overnight period, however, dense cloud cover and slowly increasing PoPs will result in temperatures holding fairly steady in the mid to upper 60s. Thus, a very mild and somewhat humid night will be in store for the Tennessee Valley. && .SHORT TERM... (Friday through Sunday) Issued at 215 PM CDT Thu May 2 2024 With the deterioration of mid level ridging, a more zonal flow pattern will allow for several shortwaves to ripple through the area through the duration of the short term and into the long term. By morning on Friday, the first of these shortwaves will be moving through the area. High (60-80%) rain chances will be present in NW AL and progress east throughout the day. Best chances for rain and storms currently look to be Friday, Saturday, and Sunday afternoon. The atmosphere will be very saturated and favorable for efficient rainfall production with periods of heavy rainfall possible all weekend. Friday there is a marginal risk (1/4) for excessive rainfall, however with QPF amounts through the weekend continuing to remain below an inch, the overall flooding threat is low. Areas that experience periods of heavy rainfall could see some brief nuisance flooding due to slow moving storms. Aside from heavy rainfall, frequent lightning from elevated thunderstorms will be the only other threat to outdoor activities this weekend. && .LONG TERM... (Sunday through Tuesday) Issued at 129 AM CDT Thu May 2 2024 Warm and active weather will continue through the long term period. By Sunday, another shortwave will track over the area, resulting in medium chances (50-60%) for showers and storms especially during the afternoon hours. This activity will likely linger through at least the early part of Monday, especially given the warm sectored airmass in place. Broad upper ridging and west/southwesterly flow aloft will keep low chances for rain and thunder in the forecast through the remainder of the long term forecast, primarily north of the TN River where better synoptic forcing will be in place. H85 temps will rise through the work week as strong southwesterly flow continues to support a warming trend, with highs could reach the 90 degree mark by on Wednesday. Overnight lows will warm each night too, beginning in the mid 60s Sunday night rising to the lower 70s Tuesday and Wednesday nights. Will definitely feel more like summer by the middle of the week! && .AVIATION... (06Z TAFS) Issued at 1233 AM CDT Fri May 3 2024 VFR conditions early this morning will give way to increased cloud cover and lower ceilings as a slow moving front sweeps into the area. High chances (60-80%) of SHRA/TSRA are forecast during the day which will produce low-end VFR to MVFR conditions due to low ceilings. A few AWWs (and amendments) may be needed especially late this afternoon and evening due to TSRA activity. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...AMP SHORT TERM....RAD LONG TERM....25 AVIATION...AMP.24 ####018006192#### FXUS63 KLOT 030534 AFDLOT Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 1234 AM CDT Fri May 3 2024 .KEY MESSAGES... - Scattered showers and thunderstorms will increase in coverage this afternoon, and continue through the overnight hours. - A few storms may be severe this afternoon with hail up to 1 inch in diameter, 60 mph winds, and soaking downpours. The severe threat should wane after sunset. - Periodic chances for showers and thunderstorms will continue from this weekend onward, with some potential for severe weather on Tuesday. && .DISCUSSION... Issued at 253 PM CDT Thu May 2 2024 Through Friday night: Showers and thunderstorms are off to an early start along the I-55 corridor, seemingly due to the interaction with an eastward-moving mid-level gravity wave and the northward-moving warm front. Additional showers and storms are expected to develop throughout the afternoon and especially after sunset as the right entrance region of an upper-level jet streak moves over the Great Lakes. As we already saw with the first batch of showers and thunderstorms, a few may pulse to severe levels with 1" hail and 60 mph "splat" downbursts through about midnight thanks to MLCAPE 1000-1250 J/kg and meager deep layer shear. With that said, widespread severe weather is not expected today, and the threat should wane with the loss of heating after sunset (though a few non-severe thunderstorms may continue through the overnight hours). Showers will likely continue through daybreak Friday as a cold front sweeps across the area. Chances for rain will then end from west to east Friday morning behind the front as drier air works into the region. Clearing skies and highs in the lower 70s are expected tomorrow afternoon, though stout northerly winds off Lake Michigan will keep lakeshore locations some 10 to 15 degrees colder, particularly in northwestern Indiana. As a surface high pressure system slides overhead tomorrow night, slacking winds and clear skies will allow for efficient radiational cooling. Overnight lows should dip into the upper 40s with locally cooler readings in typical cold spots. If drier guidance verifies (allowing for even more efficient radiational cooling), some lower 40 degree readings cannot be ruled out. Borchardt Saturday through Thursday: Primary forecast concerns are the potential for severe thunderstorms Tuesday and possibly isolated strong/severe thunderstorms Saturday afternoon/evening. The models are now showing a compact system moving across the local area Saturday afternoon/evening with a chance for thunderstorms. The ensembles are in reasonable agreement for this potential and there is some instability. There will be the potential for a few strong/severe storms during peak heating in the afternoon/early evening. Blended pops are generally in the low chance range but these may need to be increased if these trends continue. Sunday looks mainly dry and there is quite a bit of uncertainty for precip chances Sunday night into Monday morning with the Canadian/ECMWF fairly dry with only the GFS showing precipitation. After the wave on Saturday afternoon/evening and as the pattern shifts into early next week, this time period may end up being dry but made no changes to the blended pops which are likely too high, in the chance range, for Sunday night into Monday. By Monday afternoon into Monday night, convection is expected to develop well west of the area and possibly reach northwest IL by daybreak Tuesday and if it does, most likely in a decaying phase. With temps likely to reach 80 and dewpoints in the 60s on Tuesday, this will provide plenty of instability for additional thunderstorms to form Tuesday afternoon and evening and some of these thunderstorms may become severe. Precipitable water values look to reach into the 1.5 to 1.75 inch range, which will allow for heavy rain. The pattern stays unsettled into the end of next week with periodic chances for showers and thunderstorms, though there will also be several dry periods. cms && .AVIATION /06Z TAFS THROUGH 12Z SATURDAY/... Issued at 1220 AM CDT Fri May 3 2024 Aviation Key Messages: - SHRA persist through pre-dawn hours. Embedded TSRA threat diminishing but non-zero, especially toward KGYY. - Period of MVFR ceilings develops pre-dawn and lingers until a cold front passes after sunrise. - Winds shift NNW with cold front after sunrise, then turn NNE- NE by mid-morning. NE winds persist through remainder of period. Somewhat diffuse area of low pressure was lifting north- northeast across eastern WI as of midnight, with a cold front trailing through far western IL into western MO. This low was associated with a mid-level disturbance over central IL, and will continue to lift northeast with the cold front moving across the terminals by sunrise. SHRA and embedded TSRA will persist ahead of the front, with TSRA growing more isolated with time, with greatest coverage of TS likely toward KGYY. MVFR ceilings along the cold frontal zone will spread across the terminals pre-dawn, eventually scattering out to VFR by mid- morning. Winds, while somewhat disorganized by earlier stronger convection, will be generally light W-SW ahead of the cold front, then shift NNW behind the front by sunrise. Winds will then continue to veer northeast by mid morning behind the front, and will generally remain northeast through the day. Winds turn light easterly Friday evening, and there is some model guidance indication that MVFR stratus may form east of the area across Lake Michigan and IN, which could drift west into the terminals later in the night. Confidence is low this far out, but have included a FEW020 mention in TAFs. Ratzer && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ Visit us at weather.gov/chicago ####018009894#### FXUS63 KJKL 030535 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 135 AM EDT Fri May 3 2024 .KEY MESSAGES... - Shower and thunderstorm chances return to the forecast Friday through Wednesday. - Cooler this weekend, though temperatures remaining above normal by 5 to 10 degrees on average from the weekend well into next week. && .UPDATE... Issued at 1145 PM EDT THU MAY 2 2024 No significant changes to the forecast with just the inclusion of the latest obs and trends for the T/Td/Sky grids with this update. These minor adjustments have been sent to the NDFD and web servers along with a freshening of zones and SAFs. UPDATE Issued at 750 PM EDT THU MAY 2 2024 23Z sfc analysis shows weak high pressure holding on over eastern Kentucky for one last evening as low pressure is advancing from the west. This pressure pattern helped push temperatures to record and near record highs on account of mostly sunny skies. Now the readings are only slowly backing down - ranging from the mid 70s to lower 80s. Meanwhile, amid light west to southwest winds, dewpoints are holding in the mid 50s to lower 60s most spots. Have mainly updated the forecast to include the latest obs and trends for the T/Td/Sky grids. These minor adjustments have been sent to the NDFD and web servers. && .SHORT TERM...(This evening through Friday night) Issued at 322 PM EDT THU MAY 2 2024 Upper ridging and surface high pressure remain the dominant weather features this afternoon, but this will begin to slowly change through the short term period. Mid-latitude cyclonic jet stream remains well northwest of the region from the Central Plains to the Upper Great Lakes region, and will remain that way through Saturday night. Meanwhile, stout and persistent upper ridging will begin to slide slowly east and weaken as persistent weak shortwaves move from the Southern Plains to the Mid-Atlantic region through Saturday night. A pronounced shortwave currently over the Arklatex region will move toward the area tonight, bringing increasing cloud cover, with shower chances toward dawn west and southwest of Somerset. Big question mark is how much does the increasing cloud cover impact tonight's low temperatures. Overall, the trend in forecast lows tonight is warmer given the warm air and moisture advection into the region, but COOP MOS still suggests lower to mid 50s for a lot of the sheltered eastern valleys. Decided to stick close to the NBM with primarily 60s outside the sheltered valleys, with local effects in the typically cooler areas given the uncertainty, though this is still a much warmer forecast than the previous shift. Showers increase through the morning from west to east, with thunderstorms becoming more likely from late morning into the afternoon especially for western and southwestern areas as instability increases. This will introduce a continuous period of high-end chance to categorical (i.e., 50 to 90 PoPs) Friday afternoon into Friday evening decreasing to high-end chance to low- end likely (50 to 60) PoPs Saturday morning. The warmest locations in our CWA will be toward Pike County Friday as this area will remain closer to the downstream ridging plus have a bit of downslope drying from light southerly flow. Highs in this area may reach well into the 80s, while highs trail off to the upper 70s across western parts of the CWA where more persistent shower and thunderstorm activity is expected. By Friday night, PoPs will be more uniform across the area, which will yield lows in the mid 50s to 60s. .LONG TERM...(Saturday through Thursday) Issued at 322 PM EDT THU MAY 2 2024 The period is expected to begin with an upper level ridge extending from the Bahamas into the Northeast Conus, an upper level low just south of Hudson Bay in northern Ontario with a shortwave trough trailing into the Upper MS to portions of the northern to central Plains. Additional weaker shortwaves should extend from the Central Plains to the Ozarks and another moving through the OH Valley to southern Appalachian region. Further west, another upper level low will be nearing the Northwest Conus with weak ridging in between this feature and trough that extending into the Central Conus. Meanwhile, a wavy frontal zone is expected to extend into the Lower OH Valley from low pressure over the eastern Great Lakes as the period begins with another sfc low southwest of Hudson Bay south to the upper MS Valley to the southern Plain to southwestern Conus. Saturday to Sunday night, the axis of the upper level ridge initially near the east coast will shift east into the western Atlantic while the upper level low initially centered in the vicinity of the southwest portion of Hudson Bay moves to Quebec. Meanwhile, the shortwave initially tracking across the Lower OH Valley and southern Appalachians should shift east of the area with another shortwave moving across the Lower OH Valley late Sat night into Sunday and another perhaps stronger shortwave that will have moved across the Southern Plains and Ozark vicinity should near the Lower OH Valley by late Sunday night. Further west, the upper level low initially near the Northwest Conus is expected to move across the western Conus/Great Basin and begin to weaken/open up as it near the Rockies Sunday night. At the sfc, the first wavy front zone is expected to cross eastern KY to begin the weekend, with the next boundary moving to the Central Great Lakes to Lower OH Valley to Southern Plains during that time as well. However, this boundary should tend to slow down and stall as it nears the OH Valley while the the western to northwest extent of this becomes warm front into eastern MT. Chances for convection should be highest on Saturday with the first passing wave and boundary with secondary peaks in convection possible with daytime heating on Sunday and perhaps late Sunday night ahead of a shortwave approaching form the southeast. Monday to Tuesday night, the consensus of the guidance is for a 500 mb shortwave trough to cross the OH Valley region Monday to Monday evening followed by shortwave rigging moving form the MS and across the Great Lakes to OH Valley and Appalachians on Tuesday. Meanwhile, the upper level low moves across portions of the Rockies and into portions of the northern Plains and an upper level trough encompasses much of the Western to Central Conus. At the sfc, a wavy boundary that may initially be stalled out near the OH River is expected to lift north as a warm front as warm front into the Great Lakes east of the sfc low as guidance suggest it moves east near the US/Canadian border to the upper MS Valley while a triple point low may reach the western Great Lakes with the trailing front should track across the Plains/portions of the Central Conus to the western Great Lakes to mid MS Valley to Southern Plains. A rather warm and moist airmass should be across the region, with passing weak shortwaves and diurnal heating leading to peaks in chances for convection each afternoon and evening with confidence greater on a peak during Monday with a passing shortwave. Wednesday to Thursday, the axis of the shortwave ridge is generally expected to shift east and southeast to a position from the Gulf of Mexico to parts of the western Atlantic with southwest flow from the Southwest Conus across the Plains/Central Conus into the OH Valley region, Southeast and Appalachians downstream of rather broad troughing. Multiple weak shortwaves could move from the Plains across the OH Valley/Southeast and across the Commonwealth during this time. Meanwhile, the sfc low well to the north of the Commonwealth should move gradually from the Great Lakes toward portions of the Great Lakes to mid Atlantic with the trailing frontal zone shearing from northeast to southwest and perhaps stalling or nearly stalling from the OH Valley to the Southern Plains regions. This boundary should interact with the passing shortwaves and heating each day with a diurnal peak in chances for convection each afternoon and evening. Temperatures will begin the period about 5 degrees above normal on Saturday even after the possible passage of the rather weak front. Then, from Monday to Thursday, the region will be in the warm sector much of the time with temperatures likely to be above normal by around 5 to 10 degrees above normal && .AVIATION...(For the 06Z TAFS through 06Z Friday night) ISSUED AT 135 AM EDT FRI MAY 3 2024 VFR conditions will prevail through the remainder of the overnight hours, as BKN to OVC middle and high level clouds continue to overspread the area. Isolated to scattered showers will begin moving near SME and LOZ between 15 and 17Z today, JKL by 20Z, SYM by 18Z, and SJS by 23Z. Showers and isolated storms will begin affecting all TAF sites by mid to late afternoon Friday, as a weakening cold front moves through the area. Winds should be primarily out of the southwest, and will peak at 5 to 10KTs Friday afternoon. With some uncertainty regarding exactly when thunderstorms will initiate today, and how widespread they will be, decided to continue the trend of VCSH from early Friday morning through Friday evening. As new model data comes, will refine the likelihood of thunder across the area as warranted && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...CMC LONG TERM...JP AVIATION...AR