Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/25/21

Area Forecast Discussion
National Weather Service La Crosse WI
1000 PM CDT Wed Mar 24 2021 .SHORT TERM...(This evening through Thursday) Issued at 204 PM CDT Wed Mar 24 2021 Forecast concerns through the short term will be the rain ending, brisk northwest winds, and if we`ll see much in the way of breaks/fog potential before the next upstream storm system heads our way. Water vapor satellite imagery highlights the closed 500mb low pressure system over the Upper Mississippi Valley with another closed low over Arizona/New Mexico. A weak shortwave was noted over the Dakotas along with a stronger open wave from the Pacific Northwest into British Columbia. The WSR-88D radar mosaic has a the deformation band precipitation is wrapping around the closed low and covers a large part of eastern Minnesota. Closer to the low and across parts of western Wisconsin, we have been seeing patches of steady rain, on and off light rain and drizzle. Through 12Z, most local rainfall reporters received at least .25 to .50 of and inch, with several locations reporting .5 to 1 inch of rainfall. Some of the higher amounts were 1.2 inches at Guttenberg Dam 10 in Clayton Co. and 1.57 inches at Necedah in Juneau Co. At Midday, surface low pressure was centered near Eau Claire with a tight pressure gradient on the west side of the low pressure system. Visible satellite imagery shows a large mass of clouds associated with this system. The RAP is fairly optimistic in losing the clouds over the southwest part of the forecast area later this evening with drier air advecting in from the west. Some mid-level moisture is expected to be drawn northeast ahead of the shortwave tracking in from the Dakotas. With the wind decoupling by morning, could see some patchy fog develop. Right now the NAM is the only one that is aggressive with it while the RAP/HRRR/LAMP data are not. Many highs occurred in the morning in the mid 40s to lower 50s. As the storm system continues to pull away, we`ll see temperatures fall through 40s into 30s. Lows tonight should be in the upper 20s to mid 30s. Moisture transport increases Thursday morning aloft, however the deep moisture (10 deg C or greater) and 850mb jet focus is more across Missouri into Illinois during the day. The 700mb warm advection does spread north into the forecast area with some steeper lapse rates as some stronger energy with part of the open wave moves into the region. The mid level frontogenesis is more focused from Missouri into Illinois. Through Thursday afternoon, the forecast area will be on the northwest edge of the precipitation. There may be some virga or sprinkles farther north, but for now will include chance of precipitation in the 15 to 30 percent range for the southern quarter of the forecast area. Highs Thursday should top out in the mid 40s to lower 50s with northeast winds 5 to 15 mph with some stronger gusts. .LONG TERM...(Thursday night through Wednesday) Issued at 204 PM CDT Wed Mar 24 2021 Over the upcoming days, the chances for additional precipitation look to be centered on the weekend and then possibly early next week, although there look to be some model differences with this system. After the system that moves past the region Thursday afternoon and night, there looks to be a brief period of some upper level ridging over the area into Friday. However, this ridging quickly breaks down with a long wave trough moving across the western conus and toward the Midwest. A short wave trough embedded in the long wave trough looks to advance northeast across the Friday night and Saturday morning followed by another short wave trough coming in from the northwest for Saturday night. The first short wave trough for Friday night looks to take a track that will go right across the local area and produce a round of moderate to possibly strong pv advection in the 500-300 mb layer. In the low levels, a weak area of low pressure is expected to move across Iowa into southern Wisconsin. In the warm air advection ahead of the surface low, good isentropic up glide should develop with this expected to be on the order of 2 to 4 ubar/s on the 290K surface. There also looks to be some moisture transport on the surface into the area, but this does not look to be all that strong. A weak to moderate band of mid-level frontogenesis should set up on the northwest side of the surface low to help form a deformation zone of precipitation. Temperatures look to be warm enough for this to fall as mainly rain, although there could be some light snow at the beginning across central Wisconsin late Friday night. The system for early next week looks to be a bit more muddled. A nearly cut off upper level low over the Desert Southwest this weekend will get kicked northeast ahead of a stronger system coming in off the northern Pacific. The differences in the models start to show up in how far north this system will come along with its strength. The 24.00Z ECMWF shows a farther north and stronger system than either the 24.12Z GFS or GEM. This spread is also apparent in the 24.00Z EPS with some members showing the system taking a farther south track with the area staying dry while some do show some light precipitation spreading over the region. The incoming system that acted as the kicker then looks to turn northeast with the upper level low moving across Canada with a trailing positive tilt long wave trough coming into the area Tuesday/Tuesday night. With the uncertainty of this system will have some low precipitation chances going from Monday night into Tuesday night. && .AVIATION...(For the 06z TAFS through 06z Thursday night) Issued at 1000 PM CDT Wed Mar 24 2021 Cigs: MVFR cigs through the evening, with improvement expected overnight as the responsible area of low pressure pulls off to the northeast. Looking to sit under a bkn deck of VFR cigs then for Thu with better chances for clearing later Thu night into Fri. WX/vsby: Some hints in a few of the meso models that patchy fog and/or low cigs could develop overnight, moreso for KRST. This is a trend that is starting to increase a bit (compared to some prev model runs). For the moment, with stay the course with no fog/low stratus - but will keep a close eye on things. Winds: west/northwest and decreasing tonight. Staying fairly light Thu and swinging more to the northeast. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Zapotocny LONG TERM...04 AVIATION...Rieck
Area Forecast Discussion
National Weather Service Binghamton NY
1041 PM EDT Wed Mar 24 2021 .SYNOPSIS... Rain will taper off this evening, followed by a warm and dry day Thursday. A low pressure system will bring more rain Thursday night into Friday. This back-and- forth weather pattern will continue this weekend; dry Saturday and more rain Sunday. && .NEAR TERM /THROUGH THURSDAY/... 1030 PM Update... Made some minor adjustments to cloud cover based on latest METSAT and observations. Also, there may still be some light rain across Catskills over the next hour or two, but removed any other mention of rain after midnight. 445 PM Update... Forecast remains mostly on-track and just made some minor adjustment to rain chances and cloud cover through this evening, based on latest observations and RADAR. Rainfall is moving out slightly faster than was previously forecast, so have adjusted accordingly. The rain moves out this evening, but low level moisture holds on across the Catskills and Poconos, with mostly cloudy conditions and fog through the night. Previous Discussion... Mosaic radar imagery shows a widespread batch of rain from central and southeast PA/eastern VA/DE/NJ north into central and eastern NY. This rain was associated with a low-level warm advection wave. The thermal structure of this wave showed that it was warm core. It will continue to move off to the northeast this afternoon and evening. In its wake the flow at 925 mb will remain moist and fairly mild with 925 mb dewpoints in the upper 40s. Below 925 mb down to the surface there was a moist southeasterly flow which was advecting temperatures in the upper 40s and lower 50s. With nightfall and some boundary layer cooling coupled with upslope flow we see a lot of low clouds and fog over the higher elevations especially Poconos/Catskills and other higher terrain areas in northeast PA and central NY. So we will continue to mention patchy to areas of fog in these areas tonight. For POPs we have switched to using the latest HRRR in the very near term hourly POPs as it has the best handle on the evolution of the precipitation shield. Later in the ESTF period, we switch back to using a blend of mesoscale model guidance for our hourly POPs. The precipitation will end in the Finger Lakes by 20z, and the rest of central NY/northeast PA by 00z or so. Then there just will be low clouds with some fog over the higher terrain tonight. For Thursday, the low-level flow turns more southwest and with subsidence, upper level ridging aloft and insolation the low clouds will break up leading to a very warm day for late March. We expect a lot of sunshine by afternoon. Some daily record highs could be challenged with maximum temperatures in the low to mid 70s. Then Thursday night, another storm system will be rapidly approaching from the lower and mid Mississippi valley. This feature will begin to spread cirrus across our area Thursday afternoon with a rapid cloud cover increase as a strong upper level jet moves into the Ohio Valley by 06z Friday. The upper level jet will induce a strong low- level southwest jet around 850 mb which noses up to NY and PA by 06z as well. This will lead to rapid developing isentropic ascent or warm air advection. Additionally, it will tap into the Gulf of Mexico and have a strong moisture feed. Thus clouds will increase between 22z Thursday and 04z Friday with precipitation breaking out as well. By 12z Friday QPF is looking like around .50" with more expected Friday. The system is moving quickly so for now not expecting any hydro issues Friday. Showalter Indices actually go below 0C late Thursday night and with strong warm advection and a sheared flow, I have added a slight chance for thunder into the grids. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... A storm system pulling out of our region and into Northern Maine will drag brisk winds across portions of Upstate NY and Northeast PA Friday. Showers will taper off Friday afternoon, with a thunderstorm possible early in the day across our northeastern counties where the atmosphere will remain unstable. As cooler, drier air moves across the lakes, winds will gust between 25 and 30 mph across most of NY and PA, with gusts of 35 mph or higher along the lake plain and over high terrain areas of the Twin Tiers. Saturday will be quiet but still milder than normal. Temperatures will reach the 50s. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... An active pattern will begin Saturday night when a low pressure system tracks out of the Great Lakes. A few rain showers could reach the western portion of our forecast area before sunrise. Showers will become likely during the day on Sunday as moisture overspreads the region. Much cooler air behind the storm will pull a mix of rain and snow showers into NY/PA Sunday night. Drier conditions will prevail Monday with a chance of lake effect rain or snow showers over the far north. Quiet weather and above normal temperatures will return for Tuesday. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... An area of lower level stratus clouds remains locked over much of the area this evening. Our area will see a persistent south- southeast flow which will upslope into the hills along and east of I-81, with more downsloping and eventual drying across the northern Finger Lakes and Syracuse area. The steady rain has exited the area at this time, but pockets of fog and drizzle are expected overnight; again mainly across the Poconos and Catskills. As for restrictions; SYR is expected to be mainly VFR overnight, but could see occasional MVFR CIGS for the next few hours. RME will remain MVFR to occasionally fuel alternate through about 09z early Thursday morning, then lifting to VFR. ITH is forecast to remain MVFR Fuel alternate due to CIG restrictions through the entire overnight period, finally scattering out and lifting to VFR between about 12-14z Thursday morning. With the south- southeast flow in place, feel at this time, that IFR restrictions are unlikely here. ELM is also at MVFR Fuel alternate CIG currently, and is also expected to remain so through the overnight. Guidance was a little more insistent that ELM could briefly see IFR or Alt Minimum CIGS for a few hours this evening, so included a tempo group in the TAF for that, between 25/02-06z. BGM will continue to see IFR CIGS overnight, and is expected to see LIFR/ Alt minimum CIGS develop after about 25/05z, continuing until 25/12-14z. At AVP, it`s currently MVFR fuel alternate and is expected to deteriorate to IFR after about 04z, then Alt Minimums possible after about 25/08z...along with some IFR vsby restrictions in fog here. For all TAF sites, expect pretty quick improvement back to VFR between about 25/13-16z, with VFR conditions then expected areawide Thursday afternoon. Some marginal LLWS still present at SYR through about 25/06z late this evening. Otherwise, expect south-southeast winds less than 10 kts overnight, becoming south-southwest 6-12 kts on Thursday. Outlook... Thursday Night through Friday...Rain showers, restrictions, and possible low level wind shear from passing low pressure system; embedded thunderstorms possible. Friday night through Saturday evening...Mainly VFR. Late Saturday night through Sunday...Another system with rain and restrictions. Some snow could briefly mix in Sunday night. Monday...VFR. && .CLIMATE... Record highs for March 25th Syracuse 78F in 1988; forecast high is 77F Binghamton 72 in 1988; forecast high is 71F Scranton/Wilkes-Barre 76 in 1910 and 1913; forecast high is 75F && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...DJN/MDP NEAR TERM...DJN/MPK SHORT TERM...DJP LONG TERM...DJP AVIATION...MJM CLIMATE...
Area Forecast Discussion
National Weather Service Cleveland OH
916 PM EDT Wed Mar 24 2021 .SYNOPSIS... Low pressure will develop over northeast Texas this evening, tracking across the mid-Mississippi Valle tomorrow and to near Lake Erie by Friday morning. High pressure will build in behind the departing low pressure on Saturday before another low moves eastward across the Great Lakes region. && .NEAR TERM /THROUGH THURSDAY NIGHT/... 915 pm update... No changes to the overnight forecast were made with this evening update. Previous discussion... Very warm conditions with partly sunny skies are currently observed across the area with surface temperatures generally in the low 70s and dew points in the upper 40s to near 50, which is a fairly pleasant day for most. RAP mesoanalysis has about 250 J/kg of MLCAPE though this is expected to increase to just over 500 J/kg with about 40 to 50 knots of vertical wind shears. Minimal MLCIN is observed in analysis data with some convective development possible over Lake Erie, far northeast Ohio, and northwest Pennsylvania later this evening. Isolated severe weather is possible given the wind profile, but it`s a long shot because of limited, skinny instability and a steadily drying airmass. Decreasing cloud cover associated with a drying airmass is expected tonight due to brief upper-level ridging. Gusty winds from earlier this afternoon should diminish and become light and variable as well tonight. A potent shortwave trough located over central Texas Thursday morning will become negatively tilted as it lifts northeast towards the Great Lakes region on Thursday and Thursday night, located near Indiana by Friday 06Z. At the surface, the low associated with this upper- level trough will work its way northeast towards the Great Lakes region during this same time period, rapidly deepening to near 990mb by 06Z Friday. Rain showers with some embedded thunderstorms will overspread the region Thursday evening, becoming more numerous Thursday night. A very strong wind field will be present with this system, producing very strong winds Thursday night, especially with the downward momentum behind the cold front, which will be working its way eastward across the forecast area between 06-12Z Friday. During this time, wind gusts of up to 50 knots will be possible, for which we have a High Wind Watch in effect for. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... A complicated and highly-variable high wind event will be ongoing across the area at the beginning of the short term period. Great uncertainty remains on the evolution of a convectively-induced, compact surface low pressure system which should be located in the vicinity of southern Lake Huron early Friday morning. Have opted to keep the high wind watch in place across the entire area at this time and will re-evaluate any potential warning/advisory changes overnight. Sometime during the early morning hours on Friday, we should switch from a warm to cold air advection regime, allowing spurts of enhanced wind just above the surface (i.e. 50 to 60 knots at 925 mb) to mix down to the surface. This would result in widespread 55 to 60 mph gusts with isolated pockets of 65 to 70 mph located within convection. not High winds should persist only for an hour or two as the enhanced pocket of wind quickly sweeps east across the region through the morning. Any higher wind gusts will quickly diminish through the morning, concluding across Northwest Pennsylvania by the early afternoon. Brief surface high pressure and upper ridging will settle in across the region Saturday morning and afternoon, making for quite a pleasant weather day with highs in the mid to upper 60s. Not anticipating much in the way of a lake breeze with the pressure gradient increasing from the west through the day, though the best chance would appear to be along the northeast lakeshore into NE OH and NW PA. By Saturday night, an upper trough and surface low pressure system will move east across the Great Lakes, increasing precipitation chances Saturday night into Sunday morning. Some elevated instability may also allow for a few rumbles of thunder as well. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... Precipitation will continue to decrease in coverage across the region Sunday morning as low pressure continues east into Quebec. This will set the stage for upper ridging and surface high pressure to settle in once again across the area, allowing for fair and quiet weather to persist through at least Monday with high temperatures in the 50s under mostly sunny skies. Fair and quiet weather may persist into Tuesday with warmer temperatures into the 60s, although some uncertainty lies on embedded shortwave trough evolution within the large scale ridge, as well as the evolution of the next large-scale trough across the Central CONUS. There is better agreement in model blends of increasing precipitation chances by Wednesday. && .AVIATION /00Z Thursday THROUGH Monday/... Generally VFR is expected through this TAF period with active and impactful weather for aviation just beyond this 24 hour TAF period. Scattered to few clouds around 7K will decrease this evening after sunset. Gusty winds from this afternoon will also slowly relax after sunset this evening. Southerly winds around 5 to 10 will continue tonight into Thursday. A low pressure system will start to approach the area late Thursday which will shift the winds from the southeast or east late in the day across western Ohio. ERI will have a light lake breeze for a couple hours this evening before shifting back from the south. High and mid level clouds will increase late in the TAF period as the next storm system approaches the region. Outlook...Non-VFR possible Thursday evening through Friday with periods of rain showers and some thunderstorms. Winds will be elevated on Friday and widespread gusts in excess of 35 knots are expected. Isolates gusts to 50 knots are possible. && .MARINE... Mainly south to southwesterly winds, 10 to 15 knots, will prevail across the lake through tonight before becoming easterly ahead of a warm front. Easterly winds will become near 20 knots by Thursday evening, increasing to near 30 knots and shifting more southerly as a warm front moves north across the lake. Southerly winds will quickly shift towards the southwest, then west, increasing to 35 knot Gales late Thursday night into Friday morning. Widespread wind gusts of near 50 knots will be possible across the lake Friday morning through the early afternoon. Given the prolonged and enhanced westerly flow, we will also likely need a low water advisory for the western basin of the lake. Westerly winds will quickly decrease to 10 knots or less by late Friday afternoon into Friday evening. Light flow across the lake is expected through Saturday. Southwest to west flow increases once again Sunday morning towards 20 to 25 knots. West to northwest flow, 20 to 25 knots, will persist through much of Sunday. A Small Craft Advisory will likely be needed. Light northwest flow will return across the lake by Sunday night into Monday. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...High Wind Watch from late Thursday night through Friday morning for OHZ010>014-020>023-030>033-038-089. High Wind Watch from late Thursday night through Friday morning for OHZ003-006>009-017>019-027>029-036-037-047. PA...High Wind Watch from Friday morning through Friday afternoon for PAZ001>003. MARINE...Gale Watch from late Thursday night through Friday morning for LEZ142>148-162>168. Gale Watch from Friday morning through Friday afternoon for LEZ149-169. && $$ SYNOPSIS...Saunders NEAR TERM...Griffin/Saunders SHORT TERM...Kahn LONG TERM...Kahn AVIATION...Griffin MARINE...Kahn
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1141 PM EDT Wed Mar 24 2021 .AVIATION... There is ample moisture underneath a deepening post frontal inversion to support some degree of low end VFR and/or MVFR based stratus. These clouds are already approaching MBS. Based on the progression of low level cold air, these clouds will slowly work southeast across the remainder of the terminals overnight. Diurnal mixing on Thursday should then erode these low clouds late morning or early afternoon. For DTW...The edge of the low level cold air and stratus is forecast to approach metro by 12Z. There is some uncertainty as to how well these clouds will hold together at metro, especially given that the cloud layer may be more shallow in this region and thus easily mixed out during the course of the morning Thurs. .DTW THRESHOLD PROBABILITIES... * Low in ceilings below 5000 feet overnight and Thursday morning. High Thursday night. && .PREV DISCUSSION... Issued at 415 PM EDT Wed Mar 24 2021 DISCUSSION... Showers expanded into Lower MI from textured cumulus that moved in from Indiana during early afternoon. These clouds and showers represent increased surface dewpoint in the moisture axis and low pressure warm sector over the region. The low level moisture and afternoon surface heating has surface based CAPE above 500 J/kg but still less than 1000 J/kg in hourly mesoanalysis. More telling is MLCAPE struggling to exceed 250 J/kg but still forecast to rise above 500 J/kg in RAP solutions. So far, this has been adequate for a couple thunderstorms in the Tri Cities area and suggests continuation of efforts to monitor convective intensity capable of facilitating strong wind gusts already in the background wind field, especially if scattered cells can congeal into linear structures along the cold front. The wide range of hi-res model guidance paints the picture of uncertainty on convective character with the forecast leaning toward a tendency for struggling organization and longevity due to overall limited instability up against the strong wind profile. The chance for higher end sub-severe wind gusts near 50 mph will be monitored as surface observations indicate gusts in the mid to upper 30 mph range within the gradient flow which are expected to peak around 40 mph even outside of convection until closer to sunset. The front then remains on schedule to sweep activity eastward followed by surface wind decoupling during early evening. Low pressure exiting Lake Superior into Canada leaves behind dry weather and pleasant temperatures in the Great Lakes tonight. Low temperatures settle only in the 40s once again with the help of clouds moving in from the Midwest post front to cover any patches of open sky left over from this evening. The weak cold front tonight stalls south of the Ohio border by morning while laying a path for the next low pressure system Thursday night into Friday. Presentation of the parent upper level circulation is strong in satellite imagery this afternoon even as it opens up while being displaced by the incoming Pacific NW jet surge. This surge of height falls maintains the long wave trough out west and is now moving into better upper air coverage and potential for additional refinement in track and intensity of the lead system. The 12Z guidance package does exhibit improved consistency across the individual deterministic runs, both regional and available hi-res at the time range, especially the NAM which has fallen much more in line on track and intensity compared to yesterday. These model trends add some confidence to a track of the surface low center roughly from Toledo to Port Huron which feeds into expectations for QPF and wind. Moisture streaming in from the Gulf coast ensures a more than adequate supply for model QPF projections in the range of 1 to 2 inches for the 24 hour period from 18Z Thursday to 18Z Friday. Stripes of locally heavy rainfall occur near the surface low track where surface based or slightly elevated convection is maximized, and in the trowal/deformation zone associated with the upper level trough however without enough separation to spare concern for any portion of SE MI before the system exits Friday morning. Assuming the track of the surface low holds, then the best potential for headline worthy wind gusts also occurs as the system exits Friday morning. Model soundings indicate easterly flow ahead of the system dominated by low level stability followed by a very dynamic NW wind shift Friday morning. This along with the contributions of low level cold advection defines the time window for wind gusts in the 40 to 50 mph range, especially closer to the Canadian border. The low pressure system is on schedule to exit the region Friday afternoon followed by weak low pressure to start the weekend. Dry weather and cooler temperatures settle in but highs are still projected to reach the 50s Saturday afternoon before the next system moves in by Saturday night. This is more of a northern stream directed short wave that carries the surface low and bulk of moisture to our north. Light rain moves out by Sunday followed by another leg down on temperatures to finish the weekend. MARINE... Moderate southwest flow continues into the evening with peak gusts likely occuring around this forecast issuance. Rain chances will come to an end by early tonight as the surface low moves across the upper Great Lakes into northern Ontario. Small craft advisories continue through the late evening before winds and waves subside as the low pushes further away from the region. A brief period of quiet marine weather follows daytime Thursday before the next, stronger low pressure system tracks into the central and southern Great Lakes. The low and accompanying rain reaches the southern lakes Thursday evening before overspreading the rest of the region Thursday night. An isolated thunderstorm can`t be ruled Friday night, best chances being over the southern half of Lake Huron south to Lake Erie. There is some uncertainty in the exact track of this deep low but looks likely the low center will track over an area somewhere between the southern portions of Lake Huron to western Lake Erie. As such, this area has the most uncertainty with winds as any deviation in track will cause significant changes in wind speed/direction. Gusts to low-end gales still look possible over the majority of Lake Huron as strong northerly flow develops behind the low Friday morning. Air temperatures behind the system do appear cool enough for a neutral to slightly unstable thermal profile over the Lake Huron allowing for stronger winds aloft to mix down to the surface. Gale Watches remain up for daytime Friday. HYDROLOGY... Scattered to numerous showers and isolated thunderstorms exit eastward this evening after producing average rainfall less than 0.25 inch. Dry weather overnight and Thursday morning is followed by a more substantial rain event Thursday night and Friday as a strong low pressure system moves through Lower Michigan. Scattered thunderstorms may occur within the broader area of showers Thursday night. Rainfall totals during this time are expected to reach 1 to 1.5 inches across the area. The rain occurs during a roughly 12 to 18 hour period which limits flooding concerns to prone urban and low lying areas before the pattern exits Friday morning. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...Gale Warning from 4 AM to 4 PM EDT Friday for LHZ362-363-421-422- 441>443-462>464. Lake St Clair...Gale Watch from late Thursday night through Friday afternoon for LCZ460. Michigan waters of Lake Erie...Gale Watch from late Thursday night through Friday afternoon for LEZ444. && $$ AVIATION.....SC DISCUSSION...BT MARINE.......KDK HYDROLOGY....BT You can obtain your latest National Weather Service forecasts online at
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
948 PM CDT Wed Mar 24 2021 .UPDATE... Issued at 947 PM CDT Wed Mar 24 2021 Latest surface analysis was showing a front extending from the Great Lakes southwestward through southern Illinois and southeast Missouri. Regional radars were showing an area of showers and thunderstorms across eastern Oklahoma with additional scattered showers over Kansas into southeastern Nebraska. The area over eastern Oklahoma was being forced by strong low level moisture convergence which the RAP has moving northeast into Missouri overnight. Latest runs of the CAMS are still showing two rounds of precipitation moving across the CWA over the next 24 hours. One will be late tonight and early tomorrow with the highest PoPs over southeast Missouri and southern Illinois and a second on Thursday afternoon and evening that will be widespread. Latest runs of the GFS/NAM are keeping the surface low over southeast Missouri, so there will continue to be some risk for a few severe thunderstorms over the southern CWA during the afternoon and early evening hours. Britt && .SHORT TERM... (Through Late Thursday Night) Issued at 324 PM CDT Wed Mar 24 2021 Stratus and stratocumulus over the northwestern half of the forecast area this afternoon should continue to gradually retreat northward through the evening as mixing and entrainment of drier air erodes its southern extent. The southern extent of this stratus has marked the approximate location of a stalled southwest to northeast oriented baroclinic zone. Otherwise, dry conditions should prevail into the first half of the night. Tonight`s low temps will fall generally into the 40Fs with light winds and increasing clouds overnight. Late tonight into early Thursday morning, a low-amplitude upper- level shortwave trough will traverse the region, strengthening mid to low-level isentropic lift and WAA. These process will aid in development an early day MCS propagating northeastward immediate south of the baroclinic zone. Current CAMS indicate the stratiform region of the MCS could spread into southeastern and east-central MO and southwestern IL with potentially an isolated thunderstorm. Following the MCS, rain showers could are expected at times throughout the day as isentropic lift and WAA continue. During the second half of Thursday, a more potent upper-level shortwave trough is progged to lift northeastward across the Midwest as it takes on an increasingly negative tilt. Strong DCVA associated with the trough and the left exit region of an upper-level jet streak will drive another, more widespread round of rain arriving Thursday afternoon and continuing into the first half of the night. A few thunderstorms will also be possible with MUCAPE of 250 to 750 J/kg across southeastern and east-central MO and southwestern IL. Recent model guidance trends have been to keep the track of the surface low associated with shortwave trough to the southeast of the forecast area. This track will favor the warm sector and surface-based instability, as well as greatest severe threat to the southeast. Currently the best chance of severe thunderstorms exists to the south and east of I-44 in MO and I-70 in IL. Despite most thunderstorms remaining elevated, >60 kt of 0-6 km wind shear and clockwise low-level curving hodographs will allow them to potentially become severe. The greatest threat will be large hail and isolated damaging winds, but a tornado cannot be ruled. Total QPF through Thursday night will generally range from 0.5 to 1.5" across the forecast area, with locally higher amounts possible. These amounts should keep flash flooding concerns low. As with the severe weather threat, the flash flooding threat will be highest to the southeast of the forecast area where more widespread thunderstorms are anticipated. Rain and thunderstorms should begin to exit the region to the northeast during the first half of Thursday night. As this occurs, the surface low will quickly deepen, leading to strengthening pressure gradient and pronounced pressure rises in its wake. These conditions will lead to concerns of strong winds late Thursday evening into night with gusts up to 35 kt possible. Pfahler .LONG TERM... (Friday through Next Wednesday) Issued at 324 PM CDT Wed Mar 24 2021 Following exit of Thursday`s upper-level trough, broad and gradual upper-level ridging is forecast to dominate the Midwest on Friday, bringing a return to dry conditions across the region. Low-level flow will also turn to the south as a low-level ridge axis shifts east of the area, allowing temps on Friday to warm to above average with increasing WAA. On Saturday, a longwave upper-level trough is expected to traverse the northern-half of the central U.S. This evolution will resulting in formation of a weak surface low in the Central Plains that will track into the Midwest along with its attendant cold front during early Saturday morning into Saturday night. These features could provide the next opportunity for rain across the region. However, weak lift inherent from the diffuse nature of the cold front and DCVA associated with the trough combined with only modest Gulf of Mexico moisture return will likely limit rain shower coverage and rainfall amounts. This notion is supported by a number of GEFS and EPS members even keeping the forecast area completely dry. Despite modest available moisture, steep mid-level lapse rates could yield instability sufficient for a few thunderstorms as well. A severe thunderstorm cannot be discounted with strong vertical wind shear expected to be in place. Saturday may also be the warmest day of the extend period with pre-frontal WAA boosting 850-hPa temps to as high as 12C, translating to high temps 10 to 15F above average. Global model guidance are in general agreement that upper-level riding will briefly dominate the area Sunday before disparities grow with potential ejection of an upper-level cutoff low from the Desert Southwest into the Central Plains ahead of an upper-level trough reaching the western U.S. Although some rain could be possible with passage of the cutoff low across the Midwest, the majority of GEFS and EPS members portray the best chances for precip during the middle of next week will be tied to arrival of the trough. After near average temps Sunday, temps will also moderate to above average ahead of the trough by the middle of next week. Pfahler && .AVIATION... (For the 00z TAFs through 00z Thursday Evening) Issued at 601 PM CDT Wed Mar 24 2021 Dry and VFR conditions are expected this evening before scattered showers moves into central and east central Missouri overnight and southwest Illinois overnight into Thursday morning. A more widespread round of showers and scattered thunderstorms will move into the terminals on Thursday afternoon. Visibilities and ceilings will drop to low MVFR/possible IFR at times on Thursday afternoon. SPECIFICS FOR KSTL: Dry weather is expected through at least 11Z before scattered showers and possible thunderstorms move into the terminals early Thursday. Do not have enough confidence in this threat to have any more than VCSH at this time. A more widespread round of showers and thunderstorms will occur on Thursday afternoon and evening, so have gone with showers starting at 18Z with IFR visibilities during the late afternoon into the evening. These showers will likely move out during the evening hours. Britt && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Melbourne FL
915 PM EDT Wed Mar 24 2021 .UPDATE... Light SSE-S flow continues along the western flank of a large high pressure ridge centered over the western Atlantic. A large swath of leftover convective debris currently streaming over the northern 2/3 CWA is thinning out, and will continue to do so overnight, leaving mostly clear skies areawide. Given the prevailing light BLYR flow is from the south, expect any overnight fog to be more patchy/shallow in nature. While the latest HRRR run shows fairly widespread/dense fog, it busted pretty hard showing the same thing taking place last night. Mild overnight low in the L60s expected for all but the Treasure Coast (M-U60s). && .AVIATION...VFR. Late night fog should be patchy and quite shallow, thus opted to run with TEMPO MIFG in that area, probably no worse than 5-6SM. && .MARINE...Latest local buoy obs show moderate NE swells continuing to subside, now down to 3-4ft. This should continue overnight with light SE to SSE flow freshening just a bit to around 10-12kt. && Cristaldi/Weitlich && .PREV DISCUSSION... /issued 402 PM EDT Wed Mar 24 2021/ Thursday...High pressure conditions will extend from the surface to the upper levels of the atmosphere as a high pressure builds near the local area. No rainfall in the forecast and temperatures will really climb, reaching the lower 90s west of I-95, with locations near the coast capping to the mid 80s. High records were included below under the Climate section. Winds will be from the south in the morning, with a southeast shift in the afternoon due to a sea breeze developing. Late week-weekend... Surface high pressure will continue to build over the western Atlantic. A mid and upper level ridge with a center over the Bahamas will stretch into Florida and the western Atlantic waters through the weekend. The location of the high will keep the region in southerly flow with a loose gradient. The strong high will keep conditions dry but hot and muggy. High temperatures will reach the mid-to-upper 80s across the coast and into the lower 90s across inland locations with dew-points in the mid-to-upper 60s. Record heat is possible through the weekend - mostly over inland locations. Lows will only drop down into the mid 60s to around 70 degrees. Next week... The ridge over the southeast will flatten slightly as a trough moves through the mid and deep south. This will bring northerly flow and slightly cooler temperatures to the Space Coast to start off the workweek. However, the area should remain mostly dry with chances of rain at this time not high enough to introduce into the long term forecast this far out. Temperatures will drop into the upper 70s to low 80s across the coast for highs with mid 80s expected for highs across areas further inland. Lows will mostly remain in the 60s through the overnight hours. && .AVIATION... VFR conditions through tonight. Fog is forecast to develop late tonight into Thu morning, which could reduce visibilities. A few Tempos were added, for KDAB to KMCO to reflect this but it could be needed southward if fog develops closer to the coast. Otherwise, light winds through Thu morning, increasing to 10-15 kt from the south. && .MARINE... Tonight-Thu...A ridge will approach the local waters tonight and Thu, which will lead to more favorable conditions over the Atlantic waters through the end of the week. Swell component will slowly subside with seas of 3-4 ft on Thursday lowering to around 3 ft Friday through Saturday and 2-3 ft Sunday through Monday. Winds will generally be out of the south-southeast with an afternoon wind increase over the Intracoastal and open marine areas. Extended...High pressure will remain over the area through the start of next week. However, an upper-level trough will track through the mid and deep south which will cause the ridge over the far southeastern CONUS and Bahamas to relax. Winds will switch on Tuesday from the east-northeast at 10-15 kt with gusts to around 23kts causing seas to build up to 5-7 feet in the Volusia and northern Brevard counties offshore waters && .FIRE WEATHER... Southerly flow around high pressure centered over the Atlantic will keep a warming trend in place through the end of the week for east central Florida. No mentionable rainfall chances are expected at least through the first part of next week. Dispersion is improving on Thursday but minimum RH will be dropping to near 35 percent across the interior. A Fire Weather Watch was issued for Thursday afternoon for the interior counties as conditions will reach the borderline of our local thresholds. ERC values are above 27 and should be increasing in the next few days. The 20 feet winds will be just below criteria. && .CLIMATE... List of high records for Thursday, Mar 25 and Friday, Mar 26 across east central Florida and the year they last occurred. Site Thu Fri Daytona Beach 88(1954) 89(1944) Leesburg 88(1975) 87(2020) Sanford 91(1949) 90(2002) Orlando 95(1929) 94(1929) Melbourne 92(1975) 90(1975) Vero Beach 91(2020) 88(2015) Fort Pierce 91(2020) 91(1935) && .HYDROLOGY... River levels on the St. Johns around Astor are forecast to remain near Action Stage of 2.0 feet through the next few days, before levels gradually decrease from the late weekend into next week. && .PRELIMINARY POINT TEMPS/POPS... DAB 62 86 64 88 / 0 0 0 0 MCO 63 91 67 92 / 0 0 0 0 MLB 65 86 68 87 / 0 0 0 0 VRB 64 87 68 87 / 0 0 0 0 LEE 63 91 65 92 / 0 0 0 0 SFB 64 90 65 91 / 0 0 0 0 ORL 66 91 67 92 / 0 0 0 0 FPR 64 87 66 88 / 0 0 0 0 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...Fire Weather Watch from Thursday afternoon through Thursday evening for Northern Lake-Okeechobee-Orange-Osceola- Southern Lake. AM...None. && $$
Area Forecast Discussion
National Weather Service San Angelo TX
628 PM CDT Wed Mar 24 2021 ...New AVIATION... .SHORT TERM... (This evening through Thursday) Issued at 249 PM CDT Wed Mar 24 2021 Early this afternoon, a stationary front was located west to east along a Big Spring, San Angelo to Brady line. A dryline was also situated across our southwestern counties and was just east of Ozona as of 2 PM. The airmass south of the front and east of the dryline was beginning to destabilize over our southeast counties, with surface based CAPES 1000-1500 J/kg noted between Sonora, Junction and San Saba per latest SPC mesoanalysis. Visible satellite imagery shows enhanced cumulus developing over this area the past couple of hours. Latest HRRR is showing some convective development around 21Z, while some of the other models were less aggressive. If storms manage to develop, large hail and damaging winds will be a concern, given the moderately unstable airmass and deep layer shear between 50 and 60 knots. More widespread showers and thunderstorms are expected to develop later this evening, as lift increases with an approaching upper trough to our west. Additional strong to severe storms will be possible from late evening into the overnight hours, with the severe threat confined to far southeast counties. The main threat again will be large hail and damaging winds. A cold front will move south across the area overnight, with precipitation ending across eastern counties late. Dry and pleasant weather is expected on Thursday, with highs in the upper 60s and lower 70s. && .LONG TERM... (Thursday night through next Wednesday) Issued at 249 PM CDT Wed Mar 24 2021 Gusty south to southwest return Friday as lee trough in West Texas strengthens. It will be warmer with highs in the lower 80s. A cold front will be moving through Saturday afternoon. Temperatures will still be seasonably warm with upper 70s in the Big Country and with lower 80s south. Low level moisture will begin flowing over cooler air at the surface Saturday an upper trough approaches from the West. Can`t rule out isolated showers Saturday night, but the best potential for showers and thunderstorms will be Sunday into Monday night. Showers taper off Monday the upper trough/low moves east of the region. It`s a little early to determine severe potential but southern sections along I-10 to Mason and Saba are only marginally unstable in the GFS model with MUCAPES of around 500 J/KG Sunday and Sunday night. This could still change, however, as moisture is one of the more difficult things for the models to predict. && .AVIATION... (00Z TAFS) Issued at 623 PM CDT Wed Mar 24 2021 Isolated convection continues to develop early this evening, but nothing very close to a terminal location. More widespread convection is still expected to develop farther north and west and much closer to terminal locations later this evening and into the early morning hours. Shortlived MVFR conditions possible with these storms. This will push east of the area and leave drier conditions by sunrise Thursday morning. Otherwise, decreasing cloud cover for Thursday with west to northwest winds at around 10 knots. && .PRELIMINARY POINT TEMPS/POPS... Abilene 43 68 48 80 / 40 5 0 0 San Angelo 43 71 47 82 / 40 0 0 0 Junction 45 74 46 84 / 60 0 0 0 Brownwood 45 70 46 81 / 60 5 0 0 Sweetwater 42 68 49 79 / 20 0 0 0 Ozona 44 71 48 81 / 30 0 0 0 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...24 LONG TERM....04 AVIATION...07