Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/21/19

Area Forecast Discussion
National Weather Service Charleston SC
923 PM EDT Sun Oct 20 2019 .SYNOPSIS... High pressure over the region tonight will begin to weaken on Monday. A frontal system will affect the area Monday night and Tuesday. High pressure will rebuild late Tuesday through Thursday before another storm system potentially moves in Friday or Saturday. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... The only meaningful change that was made for the late evening update was the make adjustments to hourly temperatures and to make further modifications to the overnight low forecast. The few runs for the higher resolution guidance has backed off slightly on the intensify of the thermal ridge noted in the earlier discussion. The rest of the forecast was unchanged. Fog: With wet grounds and light/calm winds expected to prevail, the various model 1000 hPa condensation pressure deficits progs suggest there could a risk for fog/stratus late tonight, especially over far interior Southeast and extending north into Allendale and Hampton Counties in South Carolina where the lowest values are forecast. However, with some model soundings showing as much as 15 kt occurring in the 975-925 hPa layer, it is unclear whether this will produce enough mechanical turbulence atop the nocturnal inversion to favor stratus over fog. Indeed, the various short-term statistical and probabilistic guidance are all showing a number of possible scenarios ranging from widespread dense fog west of the I-95 corridor to very little fog or stratus. At this point, think the best course of action is hold the forecast pretty much as is showing patchy fog and stratus in the various sky and weather grids until a more definitive trend begins to emerge. Did opt to include an "areas of" qualifier to the fog across far interior Southeast Georgia where both the H3R and RAP show 1000 hPa condensation pressure deficits less than 15 hPa. Temperatures: Modest radiational conditions will occur for much of the night before fog/stratus begins to interrupt the radiative process. Interestingly, the NAM12, RAP and H3R all show some sort of boundary layer thermal ridge forming in the Saint George-Givhans-West Ashley-Johns Island corridor after midnight, which corresponds to about a 40 NM wide area of higher surface temperatures. There is no apparent fog/stratus layer noted in the various derived fields in this region with the better fog/stratus parameter progged to occur well to the west and southwest of this area, so it is unclear what is the cause of this feature. Still, given the nearly unanimous agreement in all three of the higher resolution guidance packages, will nudge overnight lows up a few degrees in this area. It will be interesting to see how/if this feature evolves overnight. Lows will range from the upper 50s/near 60 well inland and over the Francis Marion National Forest to the mid- upper 60s at the beaches. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Monday: We maintained a dry forecast as deep layered dry air persists above 850 MB for much of the region. Weak return flow across far Southeast GA will extend west along the Gulf Coast as a broad baroclinic zone will be in a genesis stage. Isolated showers may develop just prior to sunset in our far southern GA coastal zones, however we preferred onset of POPs to fall into the Monday night period. Skies should become partly cloudy most areas by afternoon with warm temps in the upper 70s to near 80 SC and lower 80s in GA. Monday night and Tuesday: Deep moisture advection is forecast on Monday night across the region as a warm front lifts north after midnight. We continue to trend upward with rain chances late night as models indicate a fairly extensive band of convective rains advancing north. Temps will rise overnight with many of our minimum temps likely occurring in the evening hours before clouds thicken and showers increasing. On Tuesday, A deep long wave trough will blanket much the U.S. east of the Rockies. Our area will see slow but steady mid level height falls as a cold front advances through the area reaching the coast in the afternoon. Showers and a few tstms will accompany and precede the front. The risk of severe weather does not look too impressive despite strong wind fields aloft and warm low-level temps prior to fropa. Latest models show instability parameters weakening during the afternoon hours as low level dew points decrease in a mixing low level environment. Highs will reach the lower to mid 80s most areas ahead of the front. Wednesday: Dry and cooler conditions as high pressure builds over the southeast states. Highs should only reach the lower to mid 70s from north to south. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Dry high pressure is expected to persist Wednesday night into Thursday before a broad upper trough pattern brings potentially unsettled weather into the weekend. There remain substantial differences in the models regarding timing of features late in the week. We expect an increase in rain chances beginning as early as Thursday afternoon but more likely Friday into Sunday. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... KCHS: VFR for much of the period. There are a few signals that a brief period of MVFR cigs could occur shortly after midnight, but confidence is in this scenario is quite low. KSAV: VFR through about 06z with increased probabilities for MVFR conditions. Shallow ground fog could occur as soon as 07z, but this risk should end as some marine-based stratocumulus moves inland from off the Atlantic and impacts the terminal. These clouds will be around 2kft and will show a TEMPO group 11-14z to reflect this. Cigs should lift back to low-end VFR by mid- morning with cigs lowering once again to MVFR during the afternoon as another storm system begins to approach. Extended Aviation Outlook: Flight restrictions possible Monday night as a warm front lifts north through the area. Cigs could lower to MVFR/IFR at times with increasing chances for showers. It should become VFR on Tuesday with brief restrictions possible in convection rains along a cold front. VFR expected mid week with chances for increasing lower clouds and showers late week. && .MARINE... Tonight: The last Small Craft Advisories have been allowed to expire. West/northwest winds will back to the north/northeast overnight as high pressure prevails in the wake of Nestor. Winds will remain 10 kt or less with seas subsiding to 1-3 ft through the night. Monday through Friday: High pressure weakening to the northeast will result in a light onshore flow Monday. The flow will veer to southwest by early Tuesday as a warm front lifts north through the waters. The surging will mainly be 15 kt or less. A cold front will move into the waters late Tuesday with much stronger surging Tuesday Night in cold air advection. We think SCA conditions are likely over GA waters beyond 20 NM with the best jetting occurring beyond 20 NM in northwest flow. There could be some gusts to 25 kt within 20 NM, but SCAs are less likely there. Winds will decrease during mid week as high pressure builds north of the waters. The decreasing trend will be short as onshore winds increase again by Thursday. Seas for much of the week will be in the 2-4 ft range, highest offshore with a period of higher seas likely near the Gulf Stream Tuesday Night and early Wednesday in gusty northwest flow. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$
Area Forecast Discussion
National Weather Service Dodge City KS
1048 PM CDT Sun Oct 20 2019 ...UPDATE TO SYNOPSIS... .SYNOPSIS... Issued at 1047 PM CDT Sun Oct 20 2019 WV imagery indicates an upper level trough of low pressure transitioning eastward across the Northern Plains into the Upper Midwest. Near the surface, a cold front is pushing east across eastern Kansas. && .SHORT TERM...(This afternoon through Monday night) Issued at 1145 AM CDT Sun Oct 20 2019 Strong 540 dm cyclone was spinning over the Nebraska panhandle at midday, and will continue to track east to near Sioux Falls, South Dakota by sunrise Monday. This storm track is dryslotting SW KS as expected, and all grids are dry. The Pacific cold front was making progress eastward across the western zones as of midday, with winds becoming NWly. NW winds will become modestly gusty behind the frontal passage through the afternoon hours, gusting 30-35 mph, especially by late afternoon as the current mid/high cloud canopy begins to clear west to east. The latest HRRR iterations show the Pacific frontal boundary clearing Barber county about 6 pm, with any convection east of our SE zones. The NW winds will weaken temporarily for a few hours near sunset, but increase again overnight, as the primary surge of NW winds arrive. Models depict 850 mb NWly winds increasing to near 50 mph around midnight. Much of this nocturnal momentum will not mix to the surface, but some of it definitely will, and NW wind gusts of 30-35 mph are expected for several hours tonight. NW winds will again relax somewhat for a few hours near sunrise. The winds will keep the boundary layer mixed and prevent full radiational cooling, with 30s west and 40s east sunrise Monday. Strong NW winds will resume shortly after sunrise Monday, as full sunshine will encourage mixing in the dry airmass. NW wind gusts of 30-40 mph will be common across the NE 1/2 of SW KS daylight Monday, with the strongest winds near Hays/I-70 nearest the departing cyclone. NW winds will be much weaker across far SW KS. 850 mb temperatures are at their coolest Monday, but allowing for full sunshine and NWly downslope momentum, afternoon temperatures in the lower to mid 60s are still expected. Monday night/Tuesday morning will be colder, as the radiational cooling process improves with diminishing NW winds. Expecting 30s all zones, at or below freezing across western zones. .LONG TERM...(Tuesday through Sunday) Issued at 200 PM CDT Sun Oct 20 2019 Tuesday will be a spectacular autumn day, with full sunshine, much less wind, and warmer temperatures in the upper 60s/near 70. 12z ECMWF indicates SW KS will remain in the warm sector on Wednesday, with afternoon temperatures in the upper 60s and lower 70s. An initial prefrontal trough is expected to bring a northerly wind shift by afternoon, and the NBM wind grids picked up on this, but little cold air advection is expected by these initial north winds. The true cold front will blast through SW KS Wednesday night with very strong north winds. 12z ECMWF builds a 1035+mb surface high north of Denver by sunrise Thursday, with an impressive pressure gradient progged Wednesday night/Thursday morning. Used the strongest wind guidance available, but fully expect that won`t be enough. Wind gusts of 50-55 mph are expected. Upslope snow is still shown by 12z ECMWF to hug the I-25 corridor, with 12z GFS drier and more progressive. As expected, NBM pops for light rain changing to light snow did increase on today`s model runs. A frontogenetic band of light rain/snow is expected to spread southward early Thursday, with 12z ECMWF QPF in the 0.10" range. All to say, this will not be a major winter storm. Intense cold north winds will be the primary impact Thursday morning. A hard freeze looks like a lock Friday morning, with all models showing a strong 1030mb surface ridge straddling SW KS and a clearing sky. Many locations will fall well down into the 20s. 12z ECMWF develops a strong cutoff low over the Texas South Plains by Friday evening, with associated rain south of SW KS. ECMWF suggests rain from this cyclone`s deformation zone may clip the SE zones Saturday, as the low ejects through Oklahoma. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 524 PM CDT Sun Oct 20 2019 Strong northwesterly winds will continue through tomorrow with some gusts over 30 knots tomorrow afternoon. VFR conditions will prevail with decreasing cloudiness. && .FIRE WEATHER... Issued at 200 PM CDT Sun Oct 20 2019 Fire danger will increase across western zones this afternoon and early evening, as clouds clear and NW winds and dry advection increase. Red flag warning was retained through 8 pm CDT. Extremely dry air (dewpoints currently near zero degrees) in eastern Colorado will advect into the western zones through this evening, with relative humidity falling rapidly as NW winds increase. Gusts of 30-35 mph are expected by late afternoon and early evening. An additional surge of strong NW winds are expected tonight, during the 10 pm - midnight timeframe, with only modest nocturnal relative humidity recovery. Regarding Monday, strong NW winds are expected, with the strongest winds north and east of Dodge City. Much lighter NW winds are expected across far SW Kansas. NW winds gusts of 30-40 mph will be common by late morning, with the strongest gusts (45-50 mph) near Hays and the NE zones. As such, winds will easily reach red flag criteria. Air will remain dry Monday, but it will also be cooler, such that relative humidity will fail to reach red flag criteria (15%) at most locations. With afternoon temperatures in the low to mid 60s, min RH of 18-20% is expected in the areas of strongest NW winds Monday. Based on relative humidity criteria, will not issue a fire weather watch, but any deviation to lower dewpoints will push conditions to red flag. At any rate, outdoor burning is strongly discouraged (especially NE of Dodge City) Monday. && .PRELIMINARY POINT TEMPS/POPS... DDC 38 62 36 67 / 0 0 0 0 GCK 35 62 32 69 / 0 0 0 0 EHA 33 63 34 69 / 0 0 0 0 LBL 35 64 31 69 / 0 0 0 0 HYS 41 60 36 65 / 0 0 0 0 P28 43 66 38 69 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JJohnson SHORT TERM...Turner LONG TERM...Turner AVIATION...Hovorka_42 FIRE WEATHER...Turner
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
706 PM CDT Sun Oct 20 2019 .AVIATION... Isolated thunderstorms are moving toward the north east of AUS. These storms should stay east of AUS as they continue for the next hour or two. All terminals are VFR at this time. MVFR ceilings will develop in the Austin and San Antonio areas later this evening and continue overnight. A cold front will move through the region early Monday and showers and thunderstorms Monday morning to Austin and San Antonio and a chance at DRT. Rain chances will end by around noon. VFR conditions will prevail Monday afternoon. && .PREV DISCUSSION... /ISSUED 259 PM CDT Sun Oct 20 2019/ SHORT TERM (Tonight through Monday Night)... The main story of the short term will be the cold front expected through tonight into tomorrow morning. Ahead of the front another warm afternoon is producing more record high temperatures. Just like yesterday the warm afternoon temperatures and abundant moisture could spark off a few late afternoon showers and thunderstorms east of the I-35 corridor. The Texas Tech WRF and last few runs of the HRRR have consistently shown this activity along and east of I-35 late this afternoon into the evening hours. Based on the latest high resolution models the front should arrive across the Edwards Plateau and Hill Country early Monday morning (between 2-4am), moving into the I-35 corridor between 5-7am, and then south through the Coastal Plains by 10am. While the best upper level jet dynamics will remain north of the area across North Texas and Oklahoma, where SPC has an enhanced risk of severe weather, decent CAPE and modest shear will create a small window for some strong, and possibly a severe storm or two across the area. The main threats will be some hail (best chances across the Hill Country early Monday morning), and damaging winds (anywhere along the broken line of storms). Because of this SPC does have parts of the Hill Country and Coastal Plains in either a Day 1 or Day 2 Marginal risk. High resolution models depict a broken line of showers and storms moving through the area. Any of these could produce a brief heavier shower, but general rainfall amounts should be light. The time of day (early morning through morning hours) should also help keep the severe risk down to just the few strong to severe storms like we saw with the last front. The front will quickly clear the area through the day with drier and cooler air filtering in behind it. Sunny skies should return by Monday afternoon with winds out of the north between 10-15 mph. Highs tomorrow should hold in the upper 70s to lower 80s, a good 10-15 degrees cooler than highs today. Because of the drier air and decent post frontal winds elevated fire weather will be a concern across the Rio Grande Plains and Edwards Plateau during the afternoon hours on Monday. LONG TERM (Tuesday through Sunday)... Tuesday and Wednesday will generally be mostly sunny and seasonable across South Central Texas. Afternoon highs will be near normal for mid to late October in the upper 70s and lower 80s. While Tuesday will see light winds and dry air remaining in place, southerly flow will make a return on Wednesday hastening the return of Gulf of Mexico moisture ahead of the next cold front. Models are still in vast disagreement with the timing of the large upper trough and cold front for Thursday. The GFS remains the most progressive of the models having a large upper trough across the Plains and a cold front that arrives mid-day on Thursday. The 12z ECMWF and 12z Canadian continued the trend of their 00z runs and remain deeper and slower with the trough and thereby are slower with the front. The Canadian is a nice compromise between the extremes of the GFS and ECMWF at this point, bringing the front through Thursday evening, with the ECMWF moving it across the area Thursday night into Friday. Regardless of the timing the front, which looks stronger than the front moving through tonight, should bring another good shot of rain for most areas along with much cooler temperatures. Highs Friday should struggle to get out of the mid 60s, and by Saturday they will only reach into the upper 60s to near 70. This means overnight lows in the 40s for Friday through Sunday morning. One important note about the ECMWF and Canadian solutions is they keep the upper trough across north Texas into the weekend, which if it verifies would keep rain chances around behind the front. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 65 78 53 80 54 / 80 40 0 0 0 Austin Bergstrom Intl Airport 66 78 49 80 51 / 70 40 0 0 0 New Braunfels Muni Airport 66 80 51 80 52 / 60 50 0 0 0 Burnet Muni Airport 60 76 50 77 51 / 90 20 0 0 0 Del Rio Intl Airport 65 86 52 84 56 / 20 - 0 0 0 Georgetown Muni Airport 62 77 49 78 52 / 90 30 0 0 0 Hondo Muni Airport 69 84 50 83 54 / 50 30 0 0 0 San Marcos Muni Airport 66 79 51 80 52 / 70 50 0 0 0 La Grange - Fayette Regional 69 79 50 80 52 / 60 60 0 0 0 San Antonio Intl Airport 69 81 53 80 55 / 60 40 0 0 0 Stinson Muni Airport 70 81 53 81 55 / 50 40 0 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Aviation...05 Short-Term/Long-Term...Platt
Area Forecast Discussion
National Weather Service Green Bay WI
842 PM CDT Sun Oct 20 2019 New Information added to update section .UPDATE... Issued at 837 PM CDT Sun Oct 20 2019 Observations and web cams continue to show dense fog developing near the lakeshore over Manitowoc, Kewaunee and Door counties. Have issued a dense fog advisory through 4 am Monday. Confidence in the expiration time is low, but most meso-model vsby forecasts show improvement by then, possibly due to increasing surface winds. The midnight shift will need to monitor to see if the headlines need to be extended. && .SHORT TERM...Tonight and Monday Issued at 309 PM CDT Sun Oct 20 2019 The latest RAP analysis and satellite/imagery show a weak high pressure system centered across Wisconsin early this afternoon. The last remnants of this morning`s low stratus and fog has pushed into Lake Michigan. Meanwhile, low pressure is moving east over South Dakota with an associated arcing band of rain. As this low intensifies as it moves northeast into Wisconsin on Monday, forecast concerns mainly revolve around precip trends, and potential for gales and lakeshore flooding. Tonight...Low pressure will move east towards the Minnesota and Iowa border by 12z Monday. Ahead of the low, will see a large swath of middle and high clouds sweep across the area. Southeast winds will also be increasing through the night as the pressure gradient tightens. The combo of cloud cover and increasing winds will lead to a warmer night, with lows ranging from the low 40s near the U.P. border to near 50 by the lakeshore. Models generally indicate that low level moisture will increase very late tonight, with progged soundings indicating that a chance of precip will increase after about 09z over central WI. The rest of the area should see dry weather hold on. Monday...The strengthening low will lift northeast across western Wisconsin through the day. A band of rain will be accompanying the low, which will move from southwest to northeast across most of the area during the morning. Some of the heaviest rain may occur during the afternoon just ahead of the dry slot where models project 100-200 j/kg of elevated cape will arrive. Therefore, some claps of thunder appear possible along with some locally heavy downpours. Decent rainfall totals of 0.5 to 1.0 inches look likely for most of the area. Gusty southeast winds to 30 or 35 mph will lead to a wind driven rain at times and large waves of 6 to 10 ft along the Lake Michigan shoreline. The synoptic pattern will be favorable for lakeshore flooding, though models do not indicate much in the way of a storm surge. However, given 6 to 10 ft waves expected, this could lead to some flooding in low lying areas along the lakeshore and beach erosion. Will hoist a lakeshore flood advisory. Lowered highs a degree or two because of the rainfall. .LONG TERM...Monday Night Through Sunday Issued at 309 PM CDT Sun Oct 20 2019 Surface and upper lows will move slowly northeast from the Minnesota Arrowhead Monday night to near Hudson`s Bay Wednesday. A period of dry weather is possible Monday evening, before showers return Monday night into Tuesday as warm air wraps around the system and arrives from the northwest. Looks like the precipitation will remain as all rain with 925 mb temperatures remaining above freezing until Wednesday. Mostly dry and cool weather should follow for the middle and end of the week. && .AVIATION...for 00Z TAF Issuance Issued at 633 PM CDT Sun Oct 20 2019 There are many aviation concerns during this TAF period, including fog potential along the lakeshore and in far northeast WI tonight, the arrival of moderate to heavy rainfall and associated MVFR/IFR flight conditions on Monday, and a significant threat of LLWS late tonight into Monday. Marine fog was impacting the Lake Michigan shoreline early this evening, and resulting in VLIFR conditions at the MTW TAF site. With continued east flow tonight, would expect the fog to continue along the coast through most of the night, though increasing winds may help improve conditions late. Another potential area of fog is in far northeast WI, where east to southeast upslope flow may result in some development after midnight. A large area of rain will arrive late tonight into early Monday, and become moderate to heavy during the late morning and early afternoon. Flight conditions are expected to deteriorate to MVFR/IFR as the steadier/heavier rains arrive and fog forms. The precipitation is expected to taper off as a dry slot arrives later in the afternoon, and flight conditions may return to VFR in some areas. Very strong southeast winds will develop above the surface late tonight into Monday morning, then veer south to southwest with time during the afternoon. Winds aloft may reach 50 to 60 knots, so significant LLWS is expected. && .MARINE... Issued at 309 PM CDT Sun Oct 20 2019 A strong low pressure system will be passing across the area on Monday and Tuesday. Ahead of the low, east to southeast winds will increase late tonight into Monday morning, with gusts on the Bay and Lake approaching 30 kts by midday. Wind gusts will peak on Monday afternoon in the 30 to 35 kt range, before subsiding somewhat on Monday evening. After winds veer to the southwest, winds are expected to increase again late Monday night into Tuesday. Gusts in the 30 to 35 kt range appear likely from late Monday night into Tuesday night. Wind gusts will be approaching gale force for much of the period from Monday morning through Tuesday night. The latest guidance suggests Tuesday into Tuesday night may have the greatest risk of gales. As a result, will issue a small craft advisory starting at 6 am Monday and only mention a few gale force gusts possible for the Bay. Later shifts may upgrade if enough support from the latest trends. Will upgrade the Gale Watch to a Gale Warning on Lake Michigan. && .GRB WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until 4 AM CDT Monday for WIZ022-040-050. Lakeshore Flood Advisory from 10 AM to 10 PM CDT Monday for WIZ022-040-050. && $$ UPDATE.........Kieckbusch SHORT TERM.....MPC LONG TERM......RDM AVIATION.......Kieckbusch MARINE.........MPC
Area Forecast Discussion
National Weather Service Northern Indiana
748 PM EDT Sun Oct 20 2019 .SYNOPSIS... Issued at 735 PM EDT Sun Oct 20 2019 Dry conditions will persist through tonight with lows in the lower 50s. Showers, and perhaps an afternoon thunderstorm, will overspread the region on Monday as a strong frontal system moves through. Temperatures then turn much cooler behind the front for the remainder of the week. && .SHORT TERM...(This Evening through Monday Night) Issued at 235 PM EDT Sun Oct 20 2019 Temperatures have warmed nicely across the area and will not fall off much tonight as influx of warmer air continues. Deepening low pressure will take shape to the southwest and track quickly NE our of Nebraska tonight and to near Lake Superior by Monday night as strong upper level trough continues to cut off and become negatively tilted. 2 features to watch for rain chances over the next 24 to 36 hours. A pre frontal trough will quickly spread rainshowers into the area after 12Z, rapidly shifting east by 18-21Z. Strongly forced line of showers and possibly some rumbles of thunder will then accompany the strong cold front set to sweep in and clear the area by 6Z Tues. Overall not sure how much rainfall we will end up in the area with best moisture influx occuring right along the front. Most locations should end up with quarter to half inch of rain with pockets of higher amounts. Non- zero severe threat still exists, but majority of models still struggle to get sufficient moisture in here to allow for stronger wind fields to aid in development. Winds will be gusty Monday afternoon and could see some locally higher gusts with the stronger showers/storms. Colder air will quickly settle in Monday night with lows back into the middle 40s. && .LONG TERM...(Monday Night through Sunday) Issued at 235 PM EDT Sun Oct 20 2019 Wrap around moisture and weak waves dropping through the NW flow will allow for at least a shot of some showers Tuesday across the north. Tuesday will also be rather breezy as stronger winds are mixed down with strong CAA. Weds should be dry as high pressure moves east with yet another trough digging in for Thursday to bring reinforcing shot of colder air into the weekend (highs Friday struggling out of the 40s in many spots. Degree of moisture return still in question so maintaining slgt chc to chc pops ahead of the system. && .AVIATION...(For the 00Z TAFS through 00Z Monday Evening) Issued at 745 PM EDT Sun Oct 20 2019 Primary focus with respect to 00 UTC terminals for northern Indiana is delay in timing and added delineation between prefrontal and frontal rainbands. Intense Plains cyclone with embedded shortwave through base over Oklahoma Panhandle this evening. The shortwave will eject to the northeast and drive a prefrontal trough with shallow convection pinwheeling through northern Indiana about midday. Timing, per HRRR and other higher-res guidance suggests a delay in onset. Provided short two hour period of tempo IFR conditions associated with passage of this succinct/strongly forced band of showers. While still a non-zero chance for late afternoon embedded thunderstorm associated with primary frontal passage, best indications for destabilization/upper jet dynamics relegated south of region. As such have again attempted to define this second band with another tempo group degradation into IFR. Strong winds noted as well with approach of system with veering through the day. Also gave some semblance to frontal passage at KSBN late in the forecast period. Later forecast iterations to continue to focus on timing and subsequent fropa at KFWA. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...Small Craft Advisory from 11 AM Monday to 11 AM EDT Tuesday for LMZ043-046. Gale Warning from 11 AM to 11 PM EDT Tuesday for LMZ043-046. && $$ SYNOPSIS...Murphy SHORT TERM...Fisher LONG TERM...Fisher AVIATION...Murphy Visit us at Follow us on Facebook...Twitter...and YouTube at:
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
907 PM CDT Sun Oct 20 2019 .UPDATE... Issued at 846 PM CDT Sun Oct 20 2019 Still have concerns about severe weather overnight, particularly to the south of the Missouri River. Thunderstorms, some severe, have developed over the central and southern Plains that have developed in a narrow axis of 500-1000 J/kg MUCAPE. 00Z upper air analysis is showing strong low level moisture advection into Missouri ahead of a upper low that is currently over Nebraska Panhandle. Latest runs of the HRRR have been consistent that QLCS will move into the western CWA after midnight that will move east into Illinois and begin to weaken after 6 am. Shear/instability parameters are similar to what was mentioned in the previous discussion, with the potential for damaging winds and brief tornadoes, particularly in the slight risk area. Britt && .SHORT TERM... (Through Late Monday Night) Issued at 315 PM CDT Sun Oct 20 2019 The main concern for tonight will be on convective trends and the possibility of severe weather. Widespread showers with embedded thunderstorms are likely along and ahead of a cold front draped southward from a surface low moving through the northern Plains. Confidence has increased in the amount of instability expected overnight tonight, with SBCAPEs approaching 500 J/kg just south of a retreating warm front. Exactly how far north this boundary gets will be key, but current indications are that it should pass north of southeast Missouri and parts of southwest Illinois very late tonight. This amount of instability combined with strong low-level shear and helicity along with the 0-3km shear vector oriented perpendicular to the line suggests both damaging winds and isolated tornadoes will be a threat in these locations. Timing wise, the highest threat should be between roughly 3-6AM. CAMS continue to suggest the QLCS will outrun the boundary to the east, exiting the CWA by early Monday morning. Only lingering rain showers are expected for the most part the rest of the morning mainly across portions of south-central Illinois. The dry slot of the midlatitude cyclone will move across the region during the day on Monday, so expect decreasing clouds along with breezy west/southwest winds. High temperatures will actually be near normal even behind the front due to deep mixing and favorable west/southwest flow off of the eastern Ozarks. Look for high temperatures to reach the low 60s to low 70s from northwest to southeast. Brisk westerly surface winds will continue through Monday night (and beyond) due to a strong pressure gradient south of a strong surface low in Wisconsin. Sky cover should be mostly clear for the area, with the exception of parts of northeast Missouri and west-central Illinois which may get clipped by the southern edge of wraparound low clouds. Temperatures Monday night should be near seasonal normals, generally in the low to mid 40s across the bi-state region. Gosselin .LONG TERM... (Tuesday through Next Sunday) Issued at 315 PM CDT Sun Oct 20 2019 The long term period will be one of typical fall temperature transitions and occasional chances for rain. Confidence begins to decrease beyond Thursday due to disagreement in guidance with respect to the finer details in the large scale pattern. A mature, occluded surface low will continue to track into the western part of the Great Lakes during the day Tuesday, as the cold front extending to its south makes eastward progress into the Ohio Valley. The associated upper level low continues to broaden through the midweek period to encapsulate the eastern two-thirds of the nation under a longwave trough. This will drop high temperatures by about 10 degrees with an H8 airmass of 0C to 5C moving overhead through the day. It also has the potential to be a windy afternoon with a stiff LLJ wrapping into the southern periphery of the low from the west. Much drier air on northwest flow should result in sunny conditions. Bufkit overview suggest mixing could be deep enough to reach 35-40 kt winds aloft for a 3-5 hour period Tuesday afternoon. Its safe to say gusts could reach 30-35 mph with sustained winds of 15-20 mph north of I-70. Winds should quickly subside through the evening as the sun sets and system pushes further north of the region. Surface high pressure builds into the gulf states late Tuesday into Wednesday, which places the region under its western edge and shifts surface flow out of the southwest. Dry conditions remain in place and allow temperatures to respond well into the 60s to near 70 degrees. This doesn`t last long, however, with another cold front dropping in from the north. The front arrives late Wednesday into Thursday bringing a much cooler airmass into the Midwest with showers possible along the front into the day Thursday. The overall spread will likely be limited by the lack of any broad support, so don`t expect any widespread rainfall at this point. It`s beyond Thursday where guidance begins to make a notable split, as mentioned in the previous updates. CMC/ECM continue to project an upper level cutoff low at the southwestern end of the overall trough, while the GFS is more progressive with a modest trough. The GFS would be the drier solution, while the other options pull a surface low out of the gulf with the northeastward progression of the upper level low. This would bring the potential for stratiform rainfall may as early as Saturday morning and potentially into Sunday. Given current spread, confidence is rather is low in any given solution with only slight chance to chance POPs through next weekend. Temperatures are likely to below normal or at least seasonably cool through the end of the period. Maples && .AVIATION... (For the 00z TAFs through 00z Monday Evening) Issued at 659 PM CDT Sun Oct 20 2019 Dry and VFR conditions are expected through 06Z. Then a line of thunderstorms are expected to move from west to east across area affect KCOU between 07-10Z and KUIN and the St. Louis are terminals between 09-13Z. These storms will likely reduce visibilities and ceilings to IFR as the move through. In addition, there may be wind gusts at or above 35 knots at KCOU and the St. Louis area terminals, most likely from the west to southwest. Thereafter, ceilings will improve to VFR early on Monday morning at the same time that winds veer to the southwest and gusts into the 20 to 30 knot range. SPECIFICS FOR KSTL: Dry and VFR conditions are expected until after 06Z. Then a line of thunderstorms is expected to move through the terminal between 09-12Z. This line will likely reduce visibilities and ceilings to IFR as the move through. In addition, there may be wind gusts at or above 30 knots, most likely from the west to southwest. Thereafter, ceilings will improve to VFR early on Monday morning at the same time that winds veer to the southwest with gusts above 20 knots possible. Britt && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
938 PM CDT Sun Oct 20 2019 .UPDATE... Issued at 938 PM CDT Sun Oct 20 2019 Couple of updates this evening. First, dry air evident on the 00z MPX sounding continues to impede the progress of rain moving into southwest MN (it`s just reaching Sioux Falls, SD as of 9 pm). As a result, further slowed the northeastward push of PoPs tonight. It really doesn`t look like this band of rain gets its act together until after 8z, when the RAP shows a good surge of moisture transport coming up out of NE IA on the LLJ. Other change was to add a wind advisory for western into southern MN Monday night into Tuesday. This is a classic high wind setup and given how high our confidence is that we will see wind gusts of at least 50 mph, seems unnecessary to wait another shift to get this out. Bigger question isn`t whether or not we need an advisory, but whether or not a warning will be needed. Monday night, RAP shows h85 winds increasing to over 60 kts on the west side of the low in a region of CAA. GFS soundings also showing occasional hours where top of the channel winds from western into southern MN are up around 55 kts, so big winds are all but a certainty, it`s just a question of how much of those winds we can tap into to possibly push us into a warning (50 kt/58 mph gusts or more). && .SHORT TERM...(This evening through Monday night) Issued at 332 PM CDT Sun Oct 20 2019 Forecast concerns for the short term are precipitation timing and extent of convective threat into Monday. Then remain wind becomes an issue late Monday afternoon/night. Thicker high clouds moving into the area now, but not fast enough to hold temperatures from warming through the mid and upper 60s over a portion of central MN. This should be the last mild day as the next storm system is poised to affect the region. Slowed the eastward progression of the precipitation band. It should work into eastern MN by 12z Monday. Isentropic lift becomes maximized over eastern MN 08z-12z period. Some threat of thunder with this activity later tonight. Will hold onto slight chance thunder for now. This works east during the day Monday as the surface low tracks close to east central MN. Dry slot may work into southern MN Monday afternoon and we decreased PoP some to account for this possibility. As the low lifts east/northeast and occludes over eastern MN late Monday afternoon, we expect wind to increase over the western CWA before 00z Tue. Model soundings suggest 45-50kt gust potential from the northwest over west central MN Monday night. Strong pressure gradient and CAA should allow winds to reach close to that potential. We decided to hold off on headlines for the moment. One more model run to hone in on finer timing details with regards to surface low. Colder air moves into the region Monday night, possible cold enough to mix in some wet snow over the northwest CWA after 06z Wed. Accumulation isn`t expected. .LONG TERM...(Tuesday through Sunday) Issued at 332 PM CDT Sun Oct 20 2019 Unsettled weather continues into the start of the long term period on Tuesday and Wednesday, and then benign conditions arrive for the last half of the week. A very tight surface pressure gradient looks to remain situated over the area until at least mid-day Tuesday. NAM/GFS Bufkit both indicate 40-50 knots at the top of the channel through Tuesday morning, with gradual decrease on Tuesday afternoon as the trough shifts farther into Ontario and the gradient relaxes. Temperatures will only moderate a few degrees Tuesday given the low level cold air advection and cloud cover/showers under the cyclonic flow regime. Highs will top out in the low/mid 40s, with chilly apparent temperatures in the 30s. On Wednesday we quickly shift into westerly large scale flow. GFS and ECMWF models continue to forecast a weak shortwave/PV feature sliding from the Plains to MS Valley region as we transition to an eastern trough/western CONUS ridge pattern. Have included chance POPS for a rain/snow mix associated with this feature, and although attendant precip amounts would mostly likely be light, could envision higher POPs once strength/timing/track details are more certain. At this point southern areas (along/south of the MN River Valley) look to be favored. From Thursday into the first half of the weekend, surface high pressure dominates the region, and brings a dry forecast with gradually moderating temperatures. Expect highs in the low/mid 50s for Saturday. By Sunday, notable differences in the models evolve with regard to the large scale pattern, but at this point we look to stay removed from forcing mechanisms for precipitation. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 704PM CDT Sun Oct 20 2019 Biggest change was to delay onset of precip by several hours at all terminals, though looking at where things are at 23z based on where hi-res models say it should be, it looks like we are finally seeing the models lock in on timing for bringing initial burst of rain in. As this initial band moves through, a complicating factor for late Mon morning through the rest of the period is that a dry slot will slide up across southeast MN and western WI, cutting off precip for a time. As this is happening, a strong deformation band of precip will get going on the west side of the low Monday afternoon over western MN, that will be sliding in behind the dry slot, bringing rain back in from west to east. For timing all of these bouts of precip, stayed close to a blend of the short term models at this point. Continued to keep thunder out of the TAFs, but we could see a few rumbles with this initial band coming in, while steep lapse rates beneath the dry slot cold promote scattered thunderstorm development in the afternoon. For cigs, they will go down fast with precip onset, a bit more uncertainty with what happens with the dry slot, as we could see significant improvements for a time before conditions crash again. KMSP...We look to be settling in on 10-12z for precip onset at MSP. Look for steady rain through about 18z, with a break Monday afternoon as the dry slot moves through, with precip and strong winds returning late in the period. /OUTLOOK FOR KMSP/ Tue...MVFR chc IFR. -SHRA likely. Wind NW at 30G40 kts. Wed...Chc MVFR. Slight chc -SHRA. Wind NNW at 10-15 kts. Thu...VFR. Wind NW at 10-15 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...Wind Advisory from 10 PM Monday to 4 PM CDT Tuesday for MNZ074- 075-082-083-091-092. Wind Advisory from 7 PM Monday to 4 PM CDT Tuesday for MNZ041- 042-047>049-054>058-064>067-073. && $$ UPDATE...MPG SHORT TERM...DWE LONG TERM...LS AVIATION...MPG
Area Forecast Discussion
National Weather Service Springfield MO
917 PM CDT Sun Oct 20 2019 .UPDATE... Issued at 914 PM CDT Sun Oct 20 2019 02z: A 994 mb surface low-pressure system in currently centered over central South Dakota. With the parent storm system now vertically stacked, ancillary low-pressure has developed along the occluding front in central Kansas. From this, a surface cold front extends from Topeka-to-Wichita-to-Enid-to-Lubbock with a surface dryline draped across the I-35 corridor. Further upstream, a broad warm sector encompasses eastern Kansas, eastern Oklahoma, and southwest Missouri with surface dewpoints in the mid-to-upper 50s. Storms, now severe, have initiated across central Oklahoma at the intersection of the surface cold front and dryline. Per the 02z RAP analysis, the right entrance region of of 120 kt, 300-mb jet streak is nosing into portions of eastern KS, eastern OK, and southwest MO. At 500 mb, a robust negatively-tilted shortwave trough is analyzed across the Central Plains with copious amounts of differential cyclonic vorticity advecting into our forecast region. At 850 mb, a 50-70 kt low-level jet is progged to nose into southwest Missouri by 06z. Meanwhile at the surface, the winds were backed. This all adds up to very strongly forced upward vertical motion across southwest Missouri with lots of shear; two ingredients for a severe weather outbreak. On the thermodynamic side, our 00z SGF sounding showed poor MLCAPE on the order of 300 J/kg and a stout capping inversion. The expectation at this time is, that as the low-level jet becomes more pronounced, moisture, shear, instability, and lapse rates will dramatically increase in the lower-levels which will help to erode the cap. Storm mode will rapidly evolve over the next hour across eastern Oklahoma. Isolated supercells will quickly congeal into a squall line as deep shear (0-6 km) vectors align roughly parallel to the cold front. As this squall line enters southwest Missouri, multiple bowing segments will develop as 0-3 km shear vectors on the order of 40 kts align more perpendicular to the squall line, allowing rear- inflow jets (RIJs) to punch downward toward the surface. As this phenomena occurs, dangerous straight-line wind gusts exceeding 70 MPH will become possible; and with 0-1 km storm-relative helicity values approaching 400 m^2/s^2 out ahead of the squall line, a few tornadoes are anticipated. At this time, it is expected that all locations along and south of Interstate 44 are at risk for severe weather late tonight into early Monday morning. && .SHORT TERM...(This afternoon through Tonight) Issued at 220 PM CDT Sun Oct 20 2019 An upper level low is currently located across the central Plains with a trough extending south into the southern Plains. Surface low pressure is located across western South Dakota with south to southeasterly winds across our region. Gulf moisture is starting to spread to the north into southern Arkansas and Oklahoma. The moisture will continue to advect north tonight ahead of the approaching system. The upper level low will move east across the Plains this evening and will send a cold front through the area late this evening into the overnight hours. Instability is currently lacking, but as the Gulf moisture continues to spread north, instability will start to increase from south to north. Instability will likely continue to increase across southern Missouri into the overnight hours. There will be a cap in place through much of this evening, but as height falls occur with the approaching upper level trough the cap will begin to weaken. Vertical wind shear will also increase as the upper level system moves across the area. Storms are expected to develop along the front across Kansas and Oklahoma by mid evening and quickly develop into a line. The line will then race east late this evening into the overnight hours. Timing: The line may start to affect extreme southeastern Kansas and far western Missouri by as early as 9 pm and should push east out of the waring area in south central Missouri by 6 am Monday morning. The deep layer shear, the increasing instability, and strong forcing with this system will support a severe storm risk. With the storm mode expected to be in the form of a line, the main severe risk will be damaging straight line winds up to 70 mph. A few of the strongest updrafts may also be capable of hail up to the size of quarters. Strong low level shear will also support the risk for spin up tornadoes within the line, mainly with surges in the line to the east or east-northeast. The better severe potential will be across southern Missouri where the better instability will be in place generally along and south of I-44. North of the interstate instability will be more limited, but with the strong forcing along the front there will still be an isolated strong to severe risk. Some lingering showers may briefly occur behind the front for a few hours, but drier air will quickly move in limiting the overall post frontal rain chances. .LONG TERM...(Monday Night through Sunday) Issued at 220 PM CDT Sun Oct 20 2019 Gusty west winds will develop on Monday with gusts to around 35 mph expected at times. A cooler air mass is expected for Monday and Tuesday with highs in the low to mid 60s and lows in the upper 30s to middle 40s. An upper level trough will dive to the southeast into the Plains on Wednesday. A head of this system gusty southerly winds will occur and allow highs to warm to around the 70 degree mark. The trough and associated cold front will move south through the area Wednesday night into Thursday night. Showers will develop across along and behind the front. A colder air mass will spread into the area on Thursday and Friday with highs in the 50s and lows in the 30s. Medium range models differ on the upper level pattern late in the week into next weekend leaving this period a lower confidence forecast. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 611 PM CDT Sun Oct 20 2019 CAMS models still consistent on developing severe storms in the plains to our west in the next couple of hours and then forming a squall line which will quickly push through the area overnight. Expecting very breezy conditions with southerly winds initially at 15 to 25 kts becoming west behind the front and convection at 20 to 30 kts. Severe storms with variable winds over 60 mph will be possible along with MVFR/IFR conditions. Outside of the convection, could see a period behind the convection of MVFR, but should go to VFR by daybreak. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ UPDATE...Albano SHORT TERM...Wise LONG TERM...Wise AVIATION...Lindenberg
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Monday) Issued at 249 PM CDT Sun Oct 20 2019 An upper level trough was centered across the western NE PNHDL early this afternoon with a trough axis extending southward into the southern high Plains. A deepening surface low was located across southwest SD, with a surface cold front extending south-southeast and then southward across west central NE into west central KS, then extending southwest into the northern TX PNHDL. This afternoon through Tonight, the upper trough will lift northeast across the central and southern Plains. DCVA ahead of the H5 trough axis will lead to strong ascent and as the surface cold front moves east, surface convergence combined with larger scale ascent will cause shower and scattered thunderstorms to develop along the front. The vertical wind shear profiles look quite favorable for severe thunderstorms. However, lack of rich moisture return will limit the instability in the warm sector ahead of the surface front across the CWA late this afternoon and evening. Some of the CAMS do show 500 to 800 J/KG of MLCAPE developing towards 00Z MON. Given curving low- level hodographs, resulting in streamwise horizontal vorticity, may provide for stronger vertical perturbation pressure gradients to cause thunderstorm updrafts to intensify despite having lower instability. Initially, there may be scattered thunderstorms developing along the cold front after 22Z across the west central counties but as the DCVA increases a line of storms may evolve through he evening hours along the front across the eastern counties of the CWA. Several CAMs show the low-level shear increasing after 00Z MON across the eastern counties of the CWA. If stronger surface based updraft do develop, then these updraft may rotate allowing for large hail and damaging wind gusts. The HRRR forecast 200-300 J/KG of 0-1 KM SRH developing by 00Z ahead of the surface front. Even if a line of storms were to develop, some of the updrafts embedded within the line may exhibit low-top supercell characteristics, but the main hazard may trend towards isolates severe wind gusts. So I cannot rule out some isolated weak tornadoes while storms remain scattered through the early afternoon hours or if a QLCS develops with meso vortices along the line. Through the mid evening hours, as the boundary layer cools, the storms will probably weaken after 3Z and may become elevated. The surface front should move east of the CWA just after 6Z monday, bringing an end to the showers and storms. Surface winds will become west-northwest behind the surface front and overnight lows will drop into the 40s. Monday the upper level trough will amplify as it lifts northeast into the upper Midwest with the H5 trough axis extending southward across MO into the LA/TX border region. West-northwest surface winds will increase through the mid morning hours and into the afternoon and become more northwesterly. wind speeds will increase to 15 to 25 MPH with some gusts up to 40 MPH. If forecast mixing heights are a bit deeper across the western counties, then the northwest winds may exceed 30 MPH with gusts up to 45 MPH. The next forecast shift may have to issue a wind advisory for north central KS. Highs Monday will only reach the upper 50s to lower 60s. .LONG TERM...(Monday night through Sunday) Issued at 249 PM CDT Sun Oct 20 2019 Monday night Through Wednesday, the northwest flow across the Plains will become zonal on Wednesday, as another H5 trough digs southeast into the central Rockies Wednesday afternoon. A broad surface ridge of high pressure will shift southeast into the gulf coast states. The northwest winds will diminish and veer to the southwest by Wednesday. Temperatures will warm slightly on Tuesday with highs reaching the lower to mid 60s. Wednesday`s highs will reach the mid to upper 60s. Wednesday night through Thursday, the H5 trough across the central Rockies will dig southeast across the Plains and begin to shear apart. The southern section of the H5 trough will amplify across west TX. A surface cold front will move southward across the CWA Wednesday night and become stationary across eastern OK and northwest AR. Light rain will develop north of the front as isentropic lift develops north of the surface front. Temperatures may get cold enough for light snow to mix in with the rain across the northwest counties of the CWA before ending during the morning hours of Thursday. The rain may linger across east central KS through Thursday afternoon but should shift southeast of the CWA as a surface low develops across east TX and moves east into LA. The Upper low across west TX will remain nearly stationary. Cloud cover with periods of light rain and low-level CAA will only allow highs to warm into the upper 40s to around 50 degrees. Friday, a surface ridge of high pressure will build southwest into eastern KS. More insolation and diminishing surface winds will allow highs to warm into the mid to upper 50s. Friday night through Saturday night, the upper low over west TX will get kicked northeast across southeast KS on Saturday, then northeast across the mid MS river valley by 12Z SUN. Periods of rain will develop late Friday night and extend through the day Saturday as DCVA provide stronger ascent. Cloud cover and rainshowers will probably only allow highs to reach the upper 40s to mid 50s. The rain should gradually end Saturday night as the upper low tracks northeast across MO. AT this time, 850mb temperatures look to be in the 5 to 10 deg C range, so the precip will be all rain. There will not be much in the way of surface CAA. Sunday, an upper level trough will dig south-southeast along the western US into the southwestern US, allowing the upper level flow to become west-southwest across the Plains. Highs on Sunday will warm into the upper 50s to lower 60s with more insolation. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 630 PM CDT Sun Oct 20 2019 Scattered tsra will be possible at MHK terminal through 03Z and then at TOP and FOE from 01Z to 05Z time period. Winds east southeast becoming west in the 03Z to 05Z time period. Cigs mainly vfr with a lowering to mvfr possible with tsra as well as mvfr vsbys. Main concern will then will be strong winds from the west developing after 12Z around 18kts with gusts to 28 kts, increasing to around 23kts with gusts to 34 kts by 18Z. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Gargan LONG TERM...Gargan AVIATION...53