Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/18/24


Area Forecast Discussion
National Weather Service Gaylord MI
1145 PM EDT Fri May 17 2024 .KEY MESSAGES... - Warm Saturday. - Weakening cold front arrives Saturday night...dwindling rain threat along it. - Sunday afternoon lake breeze convection near Lake Huron? (Definitely a non-zero probability) - Weather more unsettled starting Monday...strong storms maybe Tuesday night? && .UPDATE... Issued at 1051 PM EDT Fri May 17 2024 Weak high pressure over much of the Great Lakes continues to produce clear skies across Northern Michigan late this evening. Spotty diurnally-induced clouds and convection have dissipated...leaving mostly clear skies across our entire CWA attm. Still expect some low status/fog development overnight across portions of Eastern Upper...far Northern and NE Lower Michigan thanks to E/SE low level flow off of the cool waters of Lake Huron. Rest of our CWA should stay mostly clear overnight. Low temps will drop into the upper 40s to lower 50s. && .SHORT TERM /THROUGH SATURDAY/... Issued at 351 PM EDT Fri May 17 2024 Pattern/Synopsis: Decaying surface front has progressed into ne lower MI. After that washes out, broader and warm southerly flow gets established tonight and especially Saturday, well ahead of low pressure in s central Canada. Forecast: With stronger surface heating finally being realized, convection has sprouted in ne lower MI, where moisture is pooled near the decaying front. SPC mesoanalysis has a skinny axis of circa 1k j/kg of MlCape extending into ne lower MI. First couple cells of the day had no problem getting strong, with one become marginally severe. Now outflow air covers a good portion of this area, though there is time for recharging. Additional cells should also cook off along the westward-moving outflow boundary, though instability is weaker with westward extent (BL moisture is less...59f dew point at APN now, vs 50 at GLR and 48 at TVC). Convection will continue to be extremely averse to moving out over chilly Lk Huron. Spotty convection should continue in ne and perhaps n central lower MI, well into evening. Have stretched out those pops a little longer. A n-s convergence line is also progged to form down the spine of central lower MI over the next few hours, thanks to continued heating. A number of HRRR runs generate convection here by early evening, then propagate it east with some marginal upscale growth. Another reason to stretch out pops a hair longer. Otherwise, diurnal cu will diminish. Light surface winds will allow for good radiational cooling. Low-level moisture will be less than this morning (except potentially for where it rains). Do have plenty of low clouds (and fog) returning to eastern upper and ne lower MI by morning. Fog/stratus should be more localized in nw lower MI. Min temps upper 40s to lower 50s. Fog/stratus should be somewhat faster to erode Saturday. Ne lower MI coastal counties, and eastern Chip/Mack Cos, could see clouds until almost lunchtime. Otherwise, mostly sunny skies, and with warm advection beginning, it`ll be toasty (away from the big lakes). Highs were boosted into the lower 80s across much of northern lower MI, with 70s along the coasts and in eastern upper MI. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... Issued at 351 PM EDT Fri May 17 2024 Pattern Forecast: Several pieces of short wave energy lined up in the northern branch wave train extending across the Pacific. First feature of interest is over the Pacific Northwest this afternoon that will swing across the upper Midwest and into northern Ontario Saturday...with another wave on its heels Sunday but this trough will dig/amplify over the western U.S. to start next week. Southwest flow aloft will predominate across the Great Lakes...with a spell of warmer and potentially more unsettled weather by midweek as a result. Lead short wave moving into Ontario will push a cold front into Michigan Sunday though it will likely tend to wash out. After that evolution of western trough and its impact on the surface pressure pattern starting Monday as an intial lee cyclone that develops as it tracks into the upper Midwest and (perhaps) the upper Lakes Tuesday but there is spread in the ideas of system evolution which will dictate timing of cooler air back into Michigan (roughly Wednesday vs. Thursday). Primary Forecast Concerns: Weakening cold front arrives Saturday night...dwindling rain threat along it: Expect a line of convection to develop along the front over western Upper/Wisconsin Saturday afternoon/evening...with the remnants moving toward northern Michigan Saturday night along a narrow low level theta-e axis coincident with the front. Better rain probabilities are indicated across eastern Upper but can`t really rule out some rogue showers popping anywhere overnight into Sunday morning (northeast Lower). Sunday afternoon lake breeze convection near Lake Huron? (Definitely a non-zero probability): Cold front looks to fall apart across Lower Michigan Sunday but a weak gradient expected to allow for lake breeze development with strongest convergence near Lake Huron. Coincidentally looks like a west-east moisture gradient is going to set up (boundary layer mean mixing ratios ranging from around 4g/kg eastern Upper to 11g/kg near Saginaw Bay. As a result dew points will likely remain in the 55-60F range roughly east of an HTL-APN line. This should generate several hundred J/kg MLCAPE values... enough to justify at least some PoPs over parts of northeast Lower (same area mentioned above). NBM probabilities are hinting at this but have blended in higher SREF PoPs to better get the idea in the forecast. Weather more unsettled starting Monday...stronger storms maybe Tuesday night?: Surge of deep moisture into the Great Lakes ahead of the digging upper trough (precipitable water values 1.25+ inch) will begin to increase rain chances on Monday (evolution of this may revolve around upstream convection which always complicates things). But arrival of the surface low and attendant warm sector into the upper Lakes on Tuesday certainly portends the potential for more significant weather...especially on the other side of Lake Michigan as usual but a nice nocturnal squall line passage could be in the offing Tuesday night. At least the setup is good for it...the devil is in the details of course. SPC Day 5 15% severe probability knocking on western Lower`s door...along with the Day 5 marginal risk the WPC Excessive Rainfall Outlook which is not unreasonable given the potential magnitude of moisture advecting northward. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 1145 PM EDT Fri May 17 2024 Weak high pressure centered over Eastern Upper and Lower Michigan will slowly push eastward overnight into Saturday. Meanwhile... an upstream cold front will slide into the Western Great Lakes region Saturday afternoon and night. Dry wx is expected across our area overnight thru Saturday evening...before chances of showers and storms begin to increase late Saturday night. Areas of low stratus/fog/IFR conditions will develop late tonight into early Saturday across Eastern Upper and far Northern/NE Lower Michigan. VFR conditions will return to this area later Saturday morning and afternoon as daytime mixing helps to lift/dissipate the low status and fog. Light/variable winds overnight will become SE under 10 kts on Saturday...lending to lake breeze development along our shoreline areas. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ UPDATE...MLR SHORT TERM...JZ LONG TERM...HAD AVIATION...MLR
Area Forecast Discussion
National Weather Service Columbia SC
907 PM EDT Fri May 17 2024 .SYNOPSIS... Chances of showers and thunderstorms will continue overnight as a weak system begins to slowly cross the region. Rich moisture across the region will keep rain chances likely lingering into Sunday. Cooler and drier air moves in for Monday and Tuesday with temperatures rebounding during the middle of next week as another ridge moves in from the west. && .NEAR TERM /UNTIL 7 AM SATURDAY MORNING/... Positively tilted upper trough continues to slowly progress through over the central/southern Plains toward the Mississippi River Valley this evening. Southwest flow aloft continues to usher in moisture with PWATs between 1.5" and 1.7" and dewpoints in the mid to upper 60s. PW values are expected to increase overnight to between 1.7" and 1.9", with a few locations closer to 2" across the CSRA/southern or eastern Midlands. Ongoing convection to our south is progged to remain out of the area tonight. However, weak short wave energy moving through the mid level flow is expected to generate scattered showers across the area amid increasing isentropic lift. The latest HRRR shows a reasonable solution, with perhaps a bit of a stronger area of showers and thunderstorms pushing through the CSRA around daybreak. Severe threat remains low though brief heavy rainfall is possible. Overcast skies and a well-mixed boundary layer keep overnight lows quite mild, only falling into the mid to upper 60s/near 70. Low dewpoint depressions may generate some reduced visibilities in and near shower activity. && .SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... Positively tilted trough will continue to slowly push eastward towards us and should be centered across the lower MS Valley by tomorrow morning. Strong flow at 500 hPa is expected to create strong shear profiles, and CAMs are generally showing some sort of MCS structure to our southwest, but how far north this gets and how fast it will be is in question. Generally, guidance has struggled with speed and placement of convective structures like this in recent weeks. So there is uncertainty about this, but confidence is high that an MCS of some sort will be in central GA at the start of this period. Ahead of this, rich moisture should favor some instability, and given the shear in the atmosphere, strong to marginally severe storms are again possible depending on the location of this convection. Thinking the best chance for this is in the southern FA, but timing and severity is hard to piece together right now. Think it`ll be approaching or through our FA by late morning, and if this happens, it opens the door for some afternoon sunshine and another round of thunderstorms in the central and northern FA. While the strongest shear will be to our east, robust instability is possible where we see sunshine tomorrow afternoon so we`ll need to watch for strong strong storms along an amorphous surface front across the northern part of SC. Highs should generally be in the mid 80s but upper 80s are possible for those that see more sunshine. Showers will probably hang around into Saturday night as the trough approaches with lows in the mid 60s expected. On Sunday, more showers and embedded thunderstorms are possible as the trough approaches and pushes over the region. Some uncertainty is present with where the surface low and resultant convergence develops, adding some overall uncertainty to rain coverage Sunday afternoon. But confidence is high that we`ll see scattered to numerous showers across much of the area, with highs in the upper 70s and low 80s. Showers should clear out on Sunday night as a back door front pushes through and pushes low PW air into the area. && .LONG TERM /MONDAY THROUGH FRIDAY/... Confidence continues to remain fairly high in the long term period. Cool and dry air is expected to remain in place on Monday, with highs well below normal near 80s. Modification quickly begins on Tuesday as high pressure shifts to our east and ridging aloft begins to build. This should carry highs back into the upper 80s and low 90s by Thursday. Another cold front is forecast to approach by the Thur/Fri timeframe, with the possibility of showers and thunderstorms in the afternoon in association with that. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... Restrictions to begin overnight and continue into Saturday. A few showers earlier this evening have moved out of the region, leaving behind VFR ceilings for the time being. After sunset, ceilings are expected to lower to eventual IFR levels after about 07z. Guidance is not as consistent at AGS/DNL for IFR, so addressed that with a TEMPO group. Low level moisture will also likely lead to areas of fog overnight with scattered showers possible. Latest guidance has been indicating less shower coverage overnight than earlier runs, but with the low level moisture in place, showers can`t be ruled out. Ceilings begin to improve after 15z or 16z, and anticipated to return to VFR after around 21z.Another round of showers and potential thunderstorms arrives late in the period. EXTENDED AVIATION OUTLOOK...Increased confidence in restrictions with showers and thunderstorms continues through Sunday night. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$
Area Forecast Discussion
National Weather Service Cleveland OH
1020 PM EDT Fri May 17 2024 .SYNOPSIS... Weak low pressure aloft will slowly push a cold front across the region tonight and Saturday. The front will wash out over the Appalachians late Saturday followed by high pressure building in Saturday night. The high will remain in control through Tuesday before low pressure and a cold front approach by Wednesday. && .NEAR TERM /THROUGH SATURDAY NIGHT/... 10:19 PM EDT Update... At time of writing, a broken line of showers/thunderstorms is continuing to persist E`ward across portions of NW PA, NE OH, and Mid-OH as the collective downshear outflow boundary interacts favorably with ambient, albeit weak, low-level vertical wind shear amidst sufficient boundary layer moisture and instability. Expect this convection to dissipate and/or exit our CWA by midnight tonight as mean mid-level flow remains W`erly and the boundary layer continues to stabilize via nocturnal cooling. A diffuse low-level convergence zone associated with a weak surface trough axis persists near a roughly Findlay to Mansfield to Meadville, PA line this late evening. This weak surface trough axis is expected to drift SE`ward and exit the rest of our CWA during the predawn hours of Saturday morning. Given continued boundary layer stabilization via nocturnal cooling through daybreak Saturday morning, the potential for additional convection to blossom along this trough axis is limited, but non-zero. A cluster of showers and thunderstorms is persisting generally S`ward over southeastern Lower MI, but expect this convection to dissipate before reaching our CWA due to aforementioned nocturnal boundary layer stabilization. However, will continue to watch this convection closely. Behind the weak surface trough, a weak and stabilizing surface ridge builds from the west and north through Saturday night, which is expected to allow fair weather to grace our entire CWA. Updated POP`s and sensible WX grids accordingly. The other concern through most of Saturday morning is fog. Nocturnal cooling amidst lingering low-level moisture, including that from recent rainfall, and a weak synoptic MSLP gradient will continue to permit the development/downward expansion of widespread stratus and radiation fog development the rest of this evening and especially early Saturday morning. Also expect limited nocturnal cooling/resulting reduction in surface dew point depressions to allow at least patchy advection fog to develop over Lake Erie overnight tonight, especially east of roughly Avon Point, OH. Issued a Dense Fog Advisory where forecast confidence is greatest in the development of at least areas of dense fog by daybreak. The advisory is in effect from 12 AM to 10 AM EDT Saturday. Any fog should dissipate by late Saturday morning, once diurnal convective mixing of the boundary layer commences and taps into drier air aloft. However, some NWP models suggest at least patchy advection fog over Lake Erie may linger well into Saturday. The rest of the forecast remains valid. Please see discussion below for further details. Previous Discussion from 3:55 PM EDT... A weak but broad mid/upper trough remains across the Great Lakes and Ohio Valley this afternoon, with associated weak surface low pressure just south of James Bay extending a cold front through Lower Michigan and Indiana. Synoptic forcing and deep layer wind profiles are very weak, but upper-level diffluence and the right entrance region of a 75-85 knot H3 jet streak lifting through the southern Great Lakes generated widespread shower activity this morning since plenty of low-level moisture is in place. The steadiest showers are currently exiting far eastern Ohio and western PA coincident with the aforementioned jet streak lifting out of the region, but breaks in the cloud cover are generating weak to moderate instability characterized by SBCAPE of 1000-1500 J/Kg in NW and north central Ohio. This combined with continued low-level moisture (dew points low/mid 60s) and upper diffluence and low-level confluence ahead of the cold front is supporting the development of diurnal convection. Doppler radar and visible satellite loops show most of this developing from north central Ohio through the central highlands at the time, but development is also taking place in Lower Michigan away from the lakes. With all of this in mind, all areas could see passing showers or thundershowers this afternoon and evening, but the greatest potential is over the southern and eastern counties from roughly Mt. Vernon to Youngstown, so put the highest PoPs there through the evening. Since the flow aloft is weak, deep layer shear values will only be 10-15 knots, so severe weather is not expected. The only concern with the convection will be locally heavy rainfall that could lead to localized, nuisance flooding. PWATs remain in the 1.3 to 1.5 inch range in much of the area which is around the 90th percentile of daily climatology for the date, and RAP forecast soundings show fairly tall, skinny CAPE with freezing levels a little above 700 mb. This combined with the weak flow profile and the flow parallel to the front will allow for some slow moving convective cells with efficient rainfall rates of 1-2 inches per hour. Any issues would likely be if convection can train. The weak mid/upper trough axis will further weaken and move east of the region tonight and Saturday allowing shortwave ridging and broad surface high pressure to nudge in from the west by Saturday night, but it looks to be a slow process since two northern and southern stream weak troughs are pretty separated from the main jets aloft. This will cause the weak cold front to slowly progress east and southeast across the region tonight and Saturday before washing out near the Appalachians. Most areas will dry out tonight, but with the front and associated low-level moisture taking their time exiting on Saturday, diurnally driven convection will develop again from late morning through the afternoon, mainly east of I-77. Coverage should however be less than today, but locally heavy downpours could occur. All areas will dry out Saturday night as the high builds in. Lows tonight will range from the upper 50s to around 60, with highs Saturday in the upper 70s/low 80s in NW and north central Ohio where more sunshine occurs, but mid 70s in NE Ohio and NW PA. Lows Saturday night will fall into the mid/upper 50s. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... The weather pattern will shift to a hotter and more summer like for later this weekend into early next week. An upper level ridge of high pressure will develop and expand over the Ohio Valley region Sunday and Monday. The main storm track will shift northward into the Upper Midwest and Upper Great Lakes region for a few days. With high pressure in control, we will expect fair weather conditions with mostly sunny to partly cloudy skies. High temperatures on Sunday afternoon will range from the lower to middle 80s. There could be a light lake breeze Sunday afternoon closer to the lakeshore that may keep temperatures in the upper 70s. We will add another degree or two for Monday afternoon with high temperatures ranging from the lower to upper 80s. We should stay dry Sunday through Monday. && .LONG TERM /TUESDAY THROUGH FRIDAY/... High pressure will continue to remain in control of our weather on Tuesday keeping us very warm and dry. Temperatures will be once again in the middle to upper 80s. By Tuesday night, the upper level ridge of high pressure will begin to break down and a series of shortwave troughs will swing through the Great Lakes region by the middle of next week. A slow moving cold front will start to slide into the Lower Great Lakes region and Ohio Valley region late Tuesday night through late Wednesday night. Showers and thunderstorms will become likely by the middle of next week. Temperatures will also be slightly cooler with the rain chances in the area Wednesday through early Thursday. && .AVIATION /00Z Saturday THROUGH Wednesday/... Mainly VFR expected through 00Z/Sun. Aloft, a weak trough axis moves E`ward through our region between ~09Z/Sat and ~18Z/Sat. Otherwise ridging precedes and follows the trough. At the surface, a weak trough affects our region through ~12Z/Sat. Thereafter, a weak ridge builds from the west and north through 00Z/Sun. Our regional surface winds trend variable around 5 knots through the TAF period. However, a NW`erly to NE`erly lake breeze around 5 to 10 knots is expected to affect locations within several miles of Lake Erie from ~15Z/Sat through 00Z/Sun. This includes KCLE and KERI. A few showers and thunderstorms with brief MVFR to IFR are expected along/near a weak low-level convergence zone accompanying the aforementioned surface trough, especially before ~04Z/Sat. This convergence zone is expected to reside near a KFDY to KMFD to KGKJ corridor. Fair weather is likely region-wide after ~12Z/Sat. Widespread low clouds and associated VFR ceilings early this evening are expected to expand and lower via nocturnal cooling amidst lingering low-level moisture. As a result, widespread MVFR to LIFR ceilings are expected to develop by this late evening or early Saturday morning. These low clouds are then expected to scatter-out or dissipate via diurnal convective mixing of the boundary layer tapping into drier air aloft late Saturday morning or early afternoon. Widespread mist and fog, and associated MVFR to LIFR visibility, are expected to develop late this evening or early Saturday morning. Mist/fog should then dissipate via the onset of diurnal heating by midday Saturday at the latest. Outlook...Non-VFR possible with periodic showers and thunderstorms on Saturday, but especially Monday night through Wednesday. && .MARINE... Overall the weather forecast for Lake Erie will remain quiet this weekend into early next week. High pressure will return over the lake this weekend with a light northeast flow under 10 knots for the weekend. A warm front will lift across the lake Monday with a return of southeast flow over the lake. Southerly flow will continue to increase up to 15 knots Tuesday and Wednesday ahead of a low pressure system that will move through the Upper Great Lakes for the middle of the week. No marine headlines are expected at this time. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Dense Fog Advisory until 10 AM EDT Saturday for OHZ009>014- 019>023-089. PA...Dense Fog Advisory until 10 AM EDT Saturday for PAZ001>003. NY...None. MARINE...None. && $$ SYNOPSIS...Garuckas NEAR TERM...Garuckas/Jaszka SHORT TERM...Griffin LONG TERM...Griffin AVIATION...Jaszka MARINE...Griffin
Area Forecast Discussion
National Weather Service Corpus Christi TX
634 PM CDT Fri May 17 2024 ...New AVIATION... .SHORT TERM... (Tonight through Saturday night) Issued at 323 PM CDT Fri May 17 2024 Key Messages: Drier tonight, warmer tomorrow Current radar shows a couple lines of showers and thunderstorms stretching from the Brush Country through the northern Coastal Plains and into the Victoria Crossroads. The HRRR and other CAM models continue to show redevelopment across the Coastal Plains and Coastal Bend this afternoon, but confidence is low at this time as the atmosphere appears to have stabilized in the wake of the cluster of thunderstorms that moves through the region late this morning. If we get enough breaks in the clouds and the atmosphere is able to destabilize with daytime heating, then the confidence for redevelopment will increase significantly. Rain chances across the region should quickly taper off this evening after sunset as PWAT values begin to decrease. As the upper-level trough continues moving eastward tonight, some vorticity will swing across the base of the trough and through South Texas, however, with PWAT values decreasing and the forcing from the upper-level jet dynamic no longer over South Texas, chances for showers and thunderstorms will be low. Ridging will begin to move into the region tomorrow promoting warmer temperatures. Despite PWAT dropping to near 1" late tonight into tomorrow, sufficient moisture will hang around to promote heat indices of 100-105 degrees area- wide. There`s also a medium chance for patchy fog to develop from the Brush Country through the Coastal Plains and into the Victoria Crossroads as light winds will combine with the moisture from the recent rainfall. && .LONG TERM... (Sunday through next Thursday) Issued at 323 PM CDT Fri May 17 2024 Key Message: A Major to Extreme risk of heat related impacts from dangerous heat next week across most of South Texas The long term period starts out with a mid-level high over Cuba and another one just south of the tip of Baja, CA. A ridge builds in over the region and keeps storm tracks further north as subsidence builds in across most of the state. The lack of deep moisture combined with subsidence will preclude any rain/storm chances throughout the long term period despite increasing PWAT`s next week. Precipitable water values start out below normal < 1.0" than onshore flow increases low level moisture with PWAT`s of around 1.50-1.75" according to the GEFS mean ensemble by the end of next week with normal values for this time of year at 1.50". Hot surface temperatures combine with high humidity resulting in dangerous heat most of the week next week with Tuesday and Wednesday looking to be the peak. Generally, there`s a Major risk of heat- related impacts for anyone without effective cooling and/or adequate hydration, much of the week with heat indices ranging up to around 110 degrees. Tuesday and Wednesday look to pose an Extreme heat risk with heat indices 110-115 degrees across much of the region. This level of rare and/or long-duration extreme heat with little to no overnight relief affects anyone without effective cooling and/or adequate hydration. Please take safety precautions and brush up on how to combat the heat at weather.gov/safety/heat && .AVIATION... (00Z TAFS) Issued at 621 PM CDT Fri May 17 2024 A few showers continue around the VCT area this evening, but will be exiting over the next couple of hours. Storms in Mexico west of COT and LRD are expected to diminish as they move toward the Rio Grande, but mid/upper levels clouds left over from the storms will likely continue to stream across S TX. MVFR CIGs are expected mainly along the coast with VCT, CRP and ALI having periods of MVFR CIGs over tonight. VSBYs are also expected to lower to MVFR/IFR for these areas toward early Saturday morning between 09-14Z due to patchy fog. The SREF is showing the probability of visibilities less than 1SM between 30-50% from ALI to VCT and 10-20% across CRP. VFR conditions are expected by mid morning Saturday with much less cloud cover due to a ridge building across S TX. && .MARINE... Issued at 323 PM CDT Fri May 17 2024 Weak to moderate northeast flow this evening will weaken and drop under 10 knots by midnight. Winds will remain weak at 10 knots or lower through tomorrow night with the winds shifting to the southeast tomorrow night. Low to medium chances for rain tonight will drop to slim (less than 10%) tomorrow as an upper-level ridge moves into the area. Weak onshore flow Sunday strengthens to weak to moderate Sunday evening before becoming Moderate Tuesday night. Weak to moderate onshore flow is expected to resume Wednesday through the end of the week. Warm and dry conditions are expected with Maximum Heat Index values 90-95F Tuesday through Friday. && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 71 93 74 93 / 10 0 0 0 Victoria 66 93 72 93 / 10 0 0 0 Laredo 71 101 75 101 / 10 0 0 0 Alice 68 97 73 96 / 10 0 0 0 Rockport 74 89 77 88 / 10 0 0 0 Cotulla 68 100 73 101 / 10 0 0 0 Kingsville 70 95 74 94 / 10 0 0 0 Navy Corpus 77 89 77 89 / 10 0 0 0 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...JCP LONG TERM....BF AVIATION...TE/81
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
835 PM CDT Fri May 17 2024 .KEY MESSAGES... - Isolated showers and storms (15-30% chance) east of the Illinois River through sunset this evening. Severe thunderstorms are not expected. - Fog development is likely tonight across eastern IL, with a 40-70% chance of visibility falling below 1 mile east of I-55. - Severe thunderstorms are possible next week on Tuesday and/or Wednesday. The exact timing remains uncertain at this range. && .UPDATE... Issued at 835 PM CDT Fri May 17 2024 Isolated thunderstorms continue along a narrow line just south of IL Rte 10 in Mason/Menard, Logan, DeWitt, Piatt, and Champaign counties. Based on how these look on radar and in satellite loops, thinking is they will diminish in next couple of hours. Then still expecting clear skies through the night with fog developing in the east and southeast parts of the CWA. Besides the isolated storms, current forecast still looks good for the rest of the area. Update should be forthcoming. Auten && .DISCUSSION... Issued at 231 PM CDT Fri May 17 2024 ** THROUGH SUNDAY ** A weakly forced pattern exists across IL this afternoon, with the state sitting between lower sfc pressure in the northern Plains and weak sfc high pressure over the mid-Atlantic. Vis sat shows two corridors of more agitated Cu development at 140pm/1840z, one from Quincy to Bloomington, and another from Shelbyville to Paris. Forecast soundings suggested 1500-2000 J/kg of SBCAPE developing, but with very weak shear (less than 20 knots), and that is well aligned with the latest RAP-based mesoanalysis. Given the weak forcing those two aforementioned corridors of enhanced Cu will be the favored area for any storm development over the next few hours. Given the weak shear, these will be short-lived, and that matches what we`ve seen with the few cells that have developed thus far. As we progress later into the afternoon, the forcing could become a little more nebulous, with a collapsing cell producing outflow that kicks off new cells, and so on. With the potential for that kind of messy evolution, maintained a 15-30% PoP east of the IL River through sunset, after which point any lingering cells will quickly diminish. Another round of fog development is possible tonight, including some dense fog, owing to a combination of light winds and mostly clear skies. Guidance has been consistent in showing the chance of fog increasing with eastward extent. 12z HREF guidance had a 40-70% chance of vis falling below 1 mile east of I-55 tonight, while the available runs of the HRRR that go out far enough show dense fog development near/east of I-57. For the weekend, central IL will be positioned between a sfc low over south-central Canada and a weak shortwave moving through the lower TN Valley. In between these two systems, upper level height rises occur over IL, resulting in mostly dry conditions and steadily warming temps. CAMs do show storm development Sat afternoon along the cold front associated with that Canadian sfc low, but it will be positioned across WI and IA, and the activity fades in the evening with the loss of heating before reaching the ILX CWA. Previously, there had been high confidence that Sunday would be dry area-wide, but now guidance is showing storms developing over east CO Sat night and progressing east along the instability gradient, which puts it on a track towards west-central IL by Sun afternoon, if it holds together. For now, the NBM introduced 15-20% PoPs which seemed reasonable given the uncertainty in the evolution of a convective complex at this range. Shear values look quite weak across our area Sunday, with deep layer shear values again below 20 knots. Temperatures do become quite warm on Sat-Sun, with highs in the mid to upper 80s which is about 10-15F above normal. Record highs for Sunday (May 19) are around 92-93F, and at this point it looks unlikely that we`ll breach those thresholds. ** EARLY NEXT WEEK ** A trough is set to amplify over the western US and send a low racing towards from the central Plains to the upper Midwest on Tuesday. Multiple days of gulf moisture advection in advance of this system will help push dewpoints near or into the low 70s. The warm-sector associated with this system continues to appear quite volatile, but mesoscale details and timing uncertainties remaining regrading the svr threat. From an ensemble perspective, the latest GEFS shows a 70-90% chance of exceeding 2000 J/kg of SBCAPE. CWASP (a parameter which combines numerous environmental factors related to severe weather into one index) is depicting values over 70 west of I-55 Tues afternoon. For reference, most EF2+ tornadoes occur in environments with CWASP values over 70. It needs to be emphasized that CWASP is just a summary of the environment, it does not factor in whether or not storms will be present in that environment. In that regard, it does look like the latest guidance has trended a bit slower with the cold front, such that the higher threat may be focused in areas west of the ILX CWA Tues afternoon. The previous forecast from the NBM had PoPs Tuesday afternoon around 60%, but the latest forecast ranges from 30% along I-70 to 60% NW of the IL River. PoPs across the ILX CWA peak during the Tues night time frame (60-80%). It`s too early to say how the severe threat could evolve into the Tues night timeframe, but perhaps the diurnal timing could be our saving grace from a higher-end severe weather outbreak. The flip side to a slower system is that it could mean a greater portion of the area is at risk for severe storms on Wednesday. With several days of convective activity needing to evolve between now and then, confidence in placement of storms on Wednesday is low, and SPC did not introduce a Day 6 Outlook area in this morning`s forecast. In summary, there is a chance for severe thunderstorms both Tuesday and Wednesday - with the latest guidance suggesting precip/severe chances increase with northwestward extent Tues afternoon, then storms push into the ILX CWA Tues evening/night. High temps remain in the 80s through Wed, then cool into the 70s for the latter half of the work week following FROPA. Erwin && .AVIATION... (For the 00z TAFs through 00z Saturday Evening) Issued at 640 PM CDT Fri May 17 2024 VFR conditions will prevail at PIA, SPI, and BMI for the next 24hrs with clear skies or scattered mid clouds at BMI due to some evening convection that is south of the site. DEC and CMI will also see clear skies or scattered mid clouds for the same reason as BMI. Some CU is expected tomorrow around 2.5kft at BMI, SPI, DEC, and CMI, but only scattered. The main concern will be fog at DEC and CMI during the morning hours with CMI seeing the lowest possible vis of 1.5 miles. Winds will be light and variable through the night and then be southerly tomorrow but still below 7 kts. Auten && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service Jacksonville FL
901 PM EDT Fri May 17 2024 ...TORNADO WATCH IN EFFECT UNTIL 1AM... ...New UPDATE, AVIATION... .UPDATE... Issued at 900 PM EDT Fri May 17 2024 For the latest NE FL and SE GA Daily Key Messages please visit: https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf A Tornado Watch will be in effect until 1 AM for areas north of the I-10 corridor west of the JAX metro area and as the Suwannee Valley Region in NE FL, and spanning northward into SE GA towards Waycross, GA. Aside from tornadoes, wind gusts of up to 70 mph will be possible as well as large hail. && .NEAR TERM...(Through Tonight) Issued at 245 PM EDT Fri May 17 2024 For the latest NE FL and SE GA Daily Key Messages please visit: https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf Another round of thunderstorms will impact the area this evening, primarily north of I-10. Convective models had a hard time pin- pointing the timing, but as of now it looks like storms will be entering the interior SE GA counties around 7-8pm, with things fizzling out just after midnight. With the sun peaking out of the clouds, enough instability will allow for strong to severe thunderstorms this evening, with the primary hazards being damaging winds and hail, but an isolated tornado and heavy rainfall cannot be ruled out. Heavy cloud cover and southerly flow overnight will keep mild lows in the lower 70s. Patchy fog will be possible over north central Florida early Saturday morning given calm winds and increased moisture. && .SHORT TERM... (Saturday through Sunday night) Issued at 245 PM EDT Fri May 17 2024 A frontal boundary will be just to our north Saturday morning while a trough of low pressure aloft moving over the region. CAM models suggest a organized cluster of storms will moving west to east from AL, FL panhandle, and south GA, but differ substantially on the timing. The HRRR brings in convection fairly early during the day but in general the HREF suggests more of a midday arrival. There is more than sufficient instability available and 0-6 km shear generally in the 40-50 kt range. The convection, if it develops earlier in the day, may allow for a quieter afternoon as the airmass will be overturned from the convection. Overall confidence is low to moderate on the timing. There is a risk of some of these storms to become severe given the combination of shear and instability. We can`t rule out an isolated tornado threat. Further south away from the front, southwest winds will be gusty at 15G25mph. Max temps could top out in the lower 90s over areas of northeast FL with resultant heat indices near 100. The front looks to bisect the forecast area Saturday evening from southwest to northeast then continue to sag southward as mid level troughing digs southeast into the region. This will continue to support elevated rain chances Saturday night. Sunday, the front looks positioned over parts of northeast FL with scattered to numerous showers and storms still possible, as upper level vort lobe swings over the area. We continued high POPs still at about 60-70 percent, which may be a little generous. Chance of showers and a few storms lingers as a surface trough/reinforcing front pushes through from north to south. && .LONG TERM... (Monday through next Friday) Issued at 245 PM EDT Fri May 17 2024 A relatively benign weather pattern looks in store for most of this period with mainly dry post-frontal airmass dominating. There may be a few lingering showers or a storm southern most areas Monday before the front clears the area to the south. The nose of sfc high pressure then expected to persist across the Carolinas and GA before moving over our forecast area Wed and Thu. Another cold frontal boundary will then move into the southeast states, possibly into north GA by Thursday. Will have some low POPs for southern zones on Monday but at most 10-20 percent chances rest of the period. The cooler airmass immediately behind the front Mon and Tue and the northeast low level flow will let highs be in the 80s, with about 80 or so at the coast due to northeast winds. However, temps ramp up again Wed and Thu to upper 80s and lower 90s as high pressure will be over the area and upper level ridge will near us. For now on Friday, just slight rain chances with persistent warming temps in the lower to mid 90s, with the weak cold front likely remaining to the north still. && .AVIATION... (00Z TAFS) Issued at 900 PM EDT Fri May 17 2024 Rain will move into the area through the early evening hours affecting mainly the northern TAF sites during the early part of the TAF period, clearing out a bit past midnight. The next round of showers and storms will look to get going during the afternoon tomorrow, with timing still uncertain. && .MARINE... Issued at 245 PM EDT Fri May 17 2024 Weak high pressure will linger rest of today before a weak area of low pressure lifts to the north tonight. A warm front will push north over the area waters. A slow moving cold front trailing the low will gradually push across the water late Saturday through Sunday, renewing chances for thunderstorms. Winds will turn northerly as high pressure wedges against a low pressure situated northeast of the waters early next week. At this time, confidence in any small craft advisory is low from northerly flow. High pressure builds directly over the waters during the middle part of next week. Rip Currents: Low surf and weak winds will keep a low risk of rip currents at area beaches. && .PRELIMINARY POINT TEMPS/POPS... AMG 72 87 68 85 / 80 80 70 60 SSI 73 88 70 85 / 40 60 80 60 JAX 73 92 70 87 / 20 40 70 70 SGJ 73 94 70 87 / 10 30 70 80 GNV 71 91 69 86 / 0 40 70 80 OCF 73 92 71 85 / 0 30 60 80 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$
Area Forecast Discussion
National Weather Service New Orleans LA
637 PM CDT Fri May 17 2024 ...New AVIATION... .SHORT TERM... (This evening through Saturday night) Issued at 428 PM CDT Fri May 17 2024 Convection has struggled to develop so far today (and we aren`t complaining). A special 18Z RAOB sounding from KLIX shows a subsidence inversion near 850 mb in wake of last night`s MCS that has helped to cap convection thus far. We are closely monitoring for convection to initiate along the quasi-stationary frontal boundary that is located just south of a line from Lafayette to Baton Rouge to Hattiesburg. This boundary has become increasingly better-defined as differential heating has magnified the temperature gradient (upper 60s/lower 70s on the cool side of the boundary and mid 80s in the warm sector). Low-level convergence has also strengthened near the front and this will provide a source of lift, but appears to be too shallow for convective updrafts to reach the LFC. Recent satellite trends show the CU field is building just south of the warm front along the Southshore, Coastal MS, and parts of coastal southeastern LA. This is the area where storms are most likely to initiate through mid afternoon. Expect coverage of storms to be widely scattered given the absence of deeper forcing. However, any storms that to break the cap has the potential to quickly become severe with an EML overhead and strong instability rooted in the boundary layer. These storms will be capable of producing locally damaging winds (favorable wet microburst environment with high instability and mid-level dry air) and large hail (steep mid- level lapse rates). The severe weather and flash flood risk quickly ramps up overnight. This is when strong forcing for ascent overspreads the area as a upper shortwave trough approaches from the Southern Plains and the region becomes located in the right entrance region of an upper- level jet streak. The afternoon cap erodes, allowing robust convection to initiate and grow upscale along the aforementioned frontal boundary. The severe and heavy rainfall threat has shifted slightly farther south given the position of the stationary front and anticipated southeastward movement of it tonight. This takes the northwestern portion of the CWA out of the primary severe wx/heavy rainfall threat area. CAMs are in good agreement showing storms quickly growing upscale and intensifying around 1 or 2 AM as the boundary progresses south of I-12. This would place the Southshore and coastal MS/SE LA under the greatest risk for heavy rainfall and severe weather during the 2-8 AM period. Similar to last night, the greatest severe weather threat will be damaging winds. It should be noted that the HRRR runs today has consistently been showing intense winds near 80 kt with the convection near the SE LA coast. There is some uncertainty regarding where the heaviest rain falls, but localized amounts of 3-4" will be possible. This will be enough to produce another round of flash flooding, especially in areas that are already saturated from the previous rounds of heavy rainfall last night and back on Monday. There was enough confidence to drop the Flood Watch for areas north and west of Baton Rouge. Meanwhile the Flood Watch was expanded a tier of zones southward to include Houma and Thibodaux but not quite all the way down to the LA coast. The watch was also extended through midday Saturday as it the storms will be slow to move offshore. && .LONG TERM... (Sunday through Thursday night) Issued at 428 PM CDT Fri May 17 2024 Dry northwesterly flow aloft will be the main driver of the weather to start the long term period. An H5 shortwave ridge axis to our west will help transition the region into a much drier pattern overall. This pattern sets in through at least midweek as upper level heights and thicknesses increase over the region. This will help most if not all of the CWFA eventually warm into the 90s sometimes early to midweek during peak heating. At the surface, high pressure will begin to move east across the southern Appalachians allowing for a moisture rich onshore flow to begin across the region...so overnight lows too will start a modest warming trend as low level moisture begins to quickly spill northward from the Gulf by Tuesday. Warm and dry conditions should continue for Wednesday and Thursday as a 594dam ridge continues to reside over northeast Mexico or Deep South Texas. The ridge will extend northeast along the US Gulf Coast and again this favors a hot pattern across the region. Up stream a surface front will try to move southward on Thursday. Globals don`t seem to agree with the progression of the front. GFS is a bit more bullish with pushing the frontal boundary through the region despite questionable upper levels (parent trough continues downstream pretty quickly). For this solution to be applicable, would expect strong convective cold pool forcing to give the front more motivation, which given the QPF is more aggressive on the GFS is plausible. ECM, however, keeps most of the QPF signal well north of our region across the Mid South. This solution doesn`t have the front move through the region...which is also a drier and warmer solution. Regardless, this is still a week out so we will hurry up and wait and see what eventually evolves through early to midweek next week. For now, lower tier POPs for the northern tier seems reasonable. && .AVIATION... (00Z TAFS) Issued at 623 PM CDT Fri May 17 2024 Frontal boundary across the middle of the CWA this afternoon has produced rather variable conditions across the terminals, ranging from IFR at KMCB to VFR at several terminals south of the boundary. The primary condition this evening should be MVFR ceilings, with a comparative lack of precipitation. As a shortwave approaches from the southwest late this evening scattered to numerous SHRA/TSRA will move across most of the terminals from southwest to northeast. Direct impacts are likely to produce IFR or lower conditions, primarily visibilities. Wind gusts to 30-40 knots will be possible with the stronger storms, and can`t rule out higher gusts. Precipitation should begin to wind down by mid- morning Saturday, with VFR conditions expected by afternoon. && .MARINE... Issued at 108 PM CDT Fri May 17 2024 The strongest winds thus far today has been present across the far southeastern coastal waters, but even here observations marginally support a SCA with occasional gusts to 20 kt. Winds have actually become light over the lakes where the pressure gradient is light near a stationary boundary. Isolated thunderstorms are expected to develop near the coast late this afternoon and early evening. Although coverage will be limited, any of these storms have the potential to produce locally strong winds in excess of 34 kt, large hail, heavy downpours, lightning, and higher seas. The risk of hazardous conditions on the waters will increase overnight and continue through Saturday morning as storms organize along the front and move southward. Some of our model guidance is showing the potential for intense convective wind gusts in excess of 50 kt, perhaps locally to hurricane strength. && .PRELIMINARY POINT TEMPS/POPS... MCB 66 84 65 88 / 60 30 0 10 BTR 70 87 70 93 / 70 30 0 0 ASD 69 84 69 92 / 70 70 0 10 MSY 71 84 73 90 / 80 70 0 10 GPT 69 81 69 89 / 80 80 10 10 PQL 69 82 67 91 / 70 80 10 10 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...Small Craft Advisory until noon CDT Saturday for LAZ068. Flood Watch through Saturday morning for LAZ036-037-039-046>048- 056>060-064-065-071-076>090. GM...Small Craft Advisory until noon CDT Saturday for GMZ530-532-534- 536-538-550-552-555-557-570-572-575-577. MS...Flood Watch through Saturday morning for MSZ077-083>088. GM...Small Craft Advisory until noon CDT Saturday for GMZ532-534-536- 538-550-552-555-557-570-572-575-577. && $$ SHORT TERM...JK LONG TERM....RDF AVIATION...RW MARINE...JK
Area Forecast Discussion
National Weather Service Marquette MI
650 PM EDT Fri May 17 2024 .KEY MESSAGES... -Breezy south winds and very warm temps in the 70s and 80s Saturday ahead of a cold front that will bring scattered afternoon/evening thunderstorms. The strongest storms may contain small hail. -Borderline elevated fire weather expected this weekend with breezy conditions on Saturday then very dry with light winds on Sunday. -More rain chances early to middle of next week as a series of disturbances moves across the area in a developing warm and moist southerly flow. && .SHORT TERM /THROUGH TONIGHT/... Issued at 346 PM EDT Fri May 17 2024 Water vapor imagery and RAP analysis show that the shortwave trof that brought shra to the area yesterday thru last evening has lifted across northern Ontario. In the wake of that wave, westerly flow prevails into Upper MI. An area of sct -shra has been moving out across western Lake Superior to the Keweenaw in an area of waa/isentropic ascent. The -shra that have reached the Keweenaw are really not much more than sprinkles. Elsewhere, skies cleared out quickly in the morning, but daytime heating led to a blossoming of cu. Stabilizing marine layer off of Lake MI and Lake Superior are evident, preventing cu. Temps have risen into the low/mid 70s F in the interior. Closer to the Lakes, temps range down into the 50s with some 40s F at lakeside locations along Lake Superior. Aforementioned waa/isentropic ascent will continue to support some -shra/sprinkles across the Keweenaw over the next few hrs. MLCAPE has increased to 100-200j/kg into far western Upper MI. This limited instability may support development of a few shra/tsra late aftn/early evening, less than 25pct chc. During the night, vigorous shortwave that is now over nw MT will swing out to ND. While the main low-level jet in response to this wave will develop ne thru MN during the night, there will be a modest increase in 850mb winds further ne across western Lake Superior this evening. The resulting increase in waa/isentropic ascent should yield some shra/tsra later this evening across northern portions of western Lake Superior and possibly also nw Upper MI, mainly the Keweenaw where fcst reflects 30pct chc. Shra/tsra associated with the main 40-50kt low-level jet developing across MN would reach western Lake Superior late tonight. Expect min temps tonight ranging from the lower 40s on the east side of the Keweenaw and near Lake MI to 55-60F in the southerly wind downslope areas far w (Ontonagon/Gogebic counties). && .LONG TERM /SATURDAY THROUGH FRIDAY/... Issued at 523 PM EDT Fri May 17 2024 Highlights of the extended forecast include very warm conditions this weekend with the potential for strong thunderstorms and elevated fire weather conditions at times. Focus shifts to widespread rain potential early/mid next week in addition to a transition to below normal temperatures by late next week. Beginning Saturday, the UP will be squarely in the warm sector of a surface low near Lake Winnipeg with 850 mb temps of 14-16C spreading across the UP. This unseasonably warm air mass will support high temps in the lower to mid 80s with the highest readings (84F+) for downsloping areas along west-central portions of our Lake Superior shoreline. Breezy south winds in the tightening gradient ahead of the approaching frontal boundary could gust as high as 30-35 mph, especially for areas favored by southerly downsloping across Gogebic and Ontonagon Counties. Southerly winds off Lake MI keeps the eastern UP mostly in the 70s to perhaps even 60s closest to Lake MI. ECMWF EFI highlights the unseasonably warm temps well, and like the model soundings, also hint at the possibility of unseasonably strong winds across the far west. The combination of hot temps and gusty winds indicates borderline elevated fire wx conditions with the main limiting factor being RH values mainly staying above 30%. However, it`s worth noting that recent RAP/HRRR guidance mixed deeper than regional/global models allowing for stronger winds and lower RHs below the 30% threshold, but was not confident enough in those solutions at this time. Timing of the incoming cold front appears increasingly favorable for thunderstorm chances across the western UP Saturday evening. The latest HREF means show QPF moving into the Ironwood area 20-21Z, with hourly rainfall rates peaking about 1-2 hours later (~6 PM). Strong frontal forcing should produce a narrow line of storms that steadily marches east suggesting peak rainfall rates may provide more accurate timing. The peak rates reach the Marquette area around 3Z (11 PM) then exit the eastern UP around 8Z (4 AM). MLCAPE values increase into the 500-1000 J/kg range in a narrow corridor ahead of the front with 30+ kts of bulk shear indicating potential for a few stronger storms. The SPC outlooked western portions of our area with 5% chances for large hail and damaging winds accordingly. It`s worth noting the 12/18z HRRR runs that developed strong outflow wind gusts in the vicinity of the Porcupine Mountains, but that may be an artifact of the deeper mixing mentioned above. A much drier air mass and associated surface ridging follows the frontal passage for Saturday night into Sunday. Abundant sunshine and light winds will result in deep mixing into extremely dry mid- levels on Sunday. For example, the 12z NAM fcst sounding valid at 18z Sunday in Ironwood indicated a -40C dew point at 779 mb. Fortunately, surface dew points won`t mix that low, but still incorporated the local mixed dew point tool to cut back on Td values resulting in min RHs closer to 20% across the interior portions of the cwa. The good news is light winds less than 10 mph should ease fire wx concerns, because critically low RHs appear nearly certain across interior portions of the UP. Lake breeze activity should limit fire wx concerns along the shorelines due to cooler temps in the 60s and higher RHs. Expect max temps reaching near 80F over much of the interior west half and mid to upper 70s over the interior east half. Models advertise a mid-level trough amplifying over the western CONUS early next week. Periodic shortwaves in a warm/moist sw flow developing ahead of the western CONUS trough will bring more rounds of showers into the area early to mid next week. The first shortwave moves through late Sun night into Monday bringing the initial batch of showers for early next week. It looks like the best chance for widespread and possibly heavy rainfall will be in the late Tue into Wed time frame when models indicate more substantial shortwave energy lifting across a nearly stationary frontal boundary draped across the area. Model uncertainty increases later into the week but it certainly looks possible that some scattered showers could linger at least into Thursday as temps trend cooler in the wake of the midweek low pressure system/frontal boundary pushing off to the east. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 649 PM EDT Fri May 17 2024 VFR will prevail thru this fcst period at IWD/CMX/SAW. Pcpn associated with a cold front will move into IWD and CMX late in the period. Gusty winds to 20+kt will then set in at IWD and CMX mid to late morning on Sat. && .MARINE... Issued at 523 PM EDT Fri May 17 2024 Stable conditions leads to light winds of generally 20 knots or less continuing into early next week, except for Saturday afternoon and evening when southerly gusts of 20-25 kts are forecast ahead of an approaching cold front. Thunderstorms are possible this evening over western and north-central portions of Lake Superior as a warm front lifts across the lake. More thunderstorms are likely on Saturday into Saturday night as the same system`s cold front moves across the lake. These storms may contain small hail, gusty and erratic winds, and frequent lightning. More thunder chances return late Sun night into Monday and then again late Tuesday into Tuesday night as a series of disturbances track northeast across the Upper Great Lakes region. Patchy fog is occurring over eastern portions of the lake and may become locally dense in areas of rainfall until the cold front brings a much drier air mass over the lake Saturday night. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...EK AVIATION...07 MARINE...EK
Area Forecast Discussion
National Weather Service Norman OK
1059 PM CDT Fri May 17 2024 ...New AVIATION... .SHORT TERM... (This evening through Saturday) Issued at 301 PM CDT Fri May 17 2024 Our upper trough will be exiting to the east through today with ridging building in behind it setting us up for a heating trend starting Saturday. The stalled surface boundary/cool front has washed out with a broad dryline stretched lee of the Colorado/New Mexico Rockies. Will maintain POPS across southeast Oklahoma this afternoon through early evening as embedded vorticity in the trough of the wave could initiate isolated elevated storms. Although weak in intensity, forecast sounding showing sufficient high-based instability (above 800 mb) for convection although shear is very weak for any organization or going severe. Visible satellite imagery was already showing some cyclonic circulation with the cloud cover over southeast Oklahoma while the latest three HRRR runs suggesting isolated convection. With no surface boundaries coming through, our surface moisture won`t be going anywhere so expect temperatures tonight to cool to the dewpoint (lower 60s) enhanced by clear night skies and light/calm winds. As a result, could see some radiational fog develop by mid-morning mainly east of I-35. Although much of the fog should be patchy, there could be some embedded areas going dense. Any fog should that develops should burn off shortly after sunrise. As previously mentioned, pressure heights will start rising Saturday as an upper ridge start building in and under sunny skies afternoon temperatures will heat about 10 degrees warmer than today with highs in the lower 90s across our western CWA to the upper 80s to the east. && .LONG TERM... (Saturday night through next Thursday) Issued at 301 PM CDT Fri May 17 2024 Gusty south winds return Sunday as well as the the dryline sharpening up across the Panhandles through west Texas as surface moisture increases across our area. Will see much of our western and northern CWA warm well into the mid 90s and although conditional, could see some convection develop east of the dryline by late afternoon but due to uncertainties with instability strength just east of the dryline will keep them very low (14-18%) but mentionable for now. Although the GFS is the weaker solution with respect to surface based instability, the ECMWF is much more aggressive in the moderate (3000 J/kg) range while deep-layer shear will be sufficient for organized severe convection in a most likely uncapped environment. The mid-level cap strengthens closer to I-35 so will keep POPs and the marginal severe risk for Sunday afternoon across all of western Oklahoma into a few of our adjacent western north Texas counties with large hail & damaging wind gusts as the potential severe hazards. If convection off the Southern High Plains does not initiate, then have a higher chance for storms with an MCS developing across Kansas through northern Oklahoma late Sunday as a shortwave digs through the westerlies. For this system, will have up to 40% POPs for elevated storms overnight extending down to I-40. Can`t rule out a few strong to marginally severe storms overnight as well. A persisting tight surface pressure gradient will maintain windy conditions Sunday night into Monday with a low-level jet developing through the night. Mixing into the jet late Monday morning could result in 30-35 mph gusts during the afternoon, and perhaps higher should the GFS solution be correct verses a weaker ECMWF solution with the strength of the jet in the afternoon. Our heating trend will peak on Monday afternoon with all of our CWA rising well in the 90s, to upper 90s across our western CWA. Both models in agreeance with the dryline punching into western Oklahoma during the afternoon. It will feel quite muggy as well ahead of the dryline with those upper 60s dewpoints, although windy conditions might bring some relief from it. Our upper ridge is scooted out on Tuesday with a broad trough digging through from the west, pushing our next cold front and the dryline through late into Wednesday. This will bring a return of storm POPs late Tuesday mainly along and east of I-35 along with a severe risk. This cold front may lift back through our area as a warm front on Thursday so will maintain POPs widespread for late next week. Although temperatures should be cooler more in the 80s after Tuesday, afternoon temperatures still trend warmer than climatically average through the end of next week. && .AVIATION... (06Z TAFS) Issued at 1025 PM CDT Fri May 17 2024 VFR conditions to continue. Light south winds and clear skies expected through the forecast period. There is some possibility of fog late tonight at DUA, but chances remain too low to introduce into TAF at this time. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 61 88 65 90 / 0 0 0 0 Hobart OK 61 92 65 93 / 0 0 0 20 Wichita Falls TX 62 92 66 93 / 0 0 0 10 Gage OK 59 93 63 95 / 0 10 10 20 Ponca City OK 59 88 63 89 / 0 0 0 10 Durant OK 62 89 65 90 / 10 0 0 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...None. TX...None. && $$ SHORT TERM...68 LONG TERM....68 AVIATION...30
Area Forecast Discussion
National Weather Service Salt Lake City UT
247 PM MDT Fri May 17 2024 .SYNOPSIS...An active, unsettled pattern will continue through at least the first half of next week. && .SHORT TERM (Through 12Z Sunday)...Another summer-like day here across the Beehive State as we head into the weekend. A mainly dry cold front has progressed through most of northern Utah, with gusty northwesterly winds in its wake. Near the front, isolated, high-based showers have formed. Given the deep, dry sub-cloud environment, cant rule out out a few microbursts this afternoon and evening...mainly south of Provo. As the initial shortwave trough shifts east into the Plains, the next shortwave trough will dig southeastward into the Pacific Northwest. In response, the remnant cold front will begin to lift north as a weak quasi-warm front. This boundary will support isolated to widely scattered high-based convection across portions of northern and central Utah Saturday afternoon into Saturday evening. A significant portion of the guidance envelope continues to support high-based convection moving into northern Utah Saturday night into Sunday morning. The main impact will be the continued potential for dry microbursts, especially during the daylight hours. .LONG TERM (After 12Z Sunday)...As we pivot to more unsettled weather this weekend, the main hazards for the long-term period include below-normal temperatures and isolated to scattered showers and thunderstorms, especially for northern Utah and southwest Wyoming. A longwave trough will push southward from the Interior Northwest and into northern Utah by Sunday. An overall lack of moisture and dynamics on Sunday will produce only isolated showers/thunderstorms over higher terrain during the afternoon and evening across northern areas. By Monday, a surface cold front will be making its way across Utah, with a slight increase in moisture and more showers/thunderstorms likely along that baroclinic zone, especially during the afternoon. Far southern Utah could see some breezy southwesterly winds Monday afternoon ahead of that frontal passage. While the main cold front will have moved eastward by Tuesday, lingering instability will likely also produce scattered showers and thunderstorms on Tuesday afternoon, particularly over higher terrain and northern areas once again. As for temperatures, highs on Monday are likely to be 10-15 degrees cooler than Sunday across many areas, with far southern Utah highs only decreasing by around 5-10 degrees. The main uncertainty here is with the track of the trough, with a more southern track (50% of ensemble members) likely producing cooler temperatures further south. A shallower trough (26% of members) would likely limit the degree of cooling over southern Utah. After a shortwave ridge on Wednesday with a warming trend, another trough is possible later in the work week. Currently, 54% of ensemble members favor a stronger trough which could produce even cooler, unsettled weather. The remaining 46% of members favor a far weaker trough and less active weather. && .AVIATION...KSLC...Northwest winds are forecast through this evening before shifting out of the southeast overnight. A light northwest wind can be expected once again early tomorrow afternoon. VFR conditions will prevail. .Rest of Utah and Southwest Wyoming...VFR conditions are forecast throughout the period across the region. Isolated rain showers are forecast for tomorrow afternoon, mainly across any central Utah terminals. Areas of gusty winds are noted this afternoon which will decrease during the evening and are forecast to be light overnight. There is, however, a chance for stronger winds after midnight at southern Utah terminals as indicated by the RAP and HRRR model solutions. Gusts around 30 knots are possible if these solutions come to fruition. && .FIRE WEATHER...Isolated high based convection continues to develop near and ahead of a cold front this afternoon...roughly near a line from Ibapah to Uinta County WY. Gusty winds are occurring behind this front, highest across areas of northern Utah closest to the Wyoming border. This front will gradually weaken through this evening as the best support lifts away from the area...and then gradually lift north as a pseudo-warm front through Sunday. Chances of high-based convection will increase with this front and continue into Sunday. Additional troughs will bring unsettled conditions into the next week. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Kruse/Cunningham/NDeSmet For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity