Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/29/19

Area Forecast Discussion
National Weather Service Gaylord MI
1142 PM EDT Sun Apr 28 2019 .UPDATE... Issued at 937 PM EDT Sun Apr 28 2019 High and mid clouds continue to filter in from the west, well ahead of low pressure way out in the plains. Most of this is still thin and sparse, and have reduced cloud cover in the early part of the night. Still anticipate thicker cloud cover arriving from w to e, though the bulk of that will occur around and after midnight. Very dry low level air in place; surface dew points mixed out deep into single digits in some spots late this afternoon. This will inhibit the ability of precip to push into northern MI. Recent Rap/HRRR runs keep this forecast area dry until after 12z/8am, in line with the going forecast. With a short period of decent radiational cooling this evening until clouds thicken and the pressure gradient tightens, have edged the min temp forecast a bit toward the low side of guidance. Temps will start to climb again before daybreak, especially in nw lower MI. && .NEAR TERM...(Through Tonight) Issued at 320 PM EDT Sun Apr 28 2019 ...Mainly quiet through tonight... High Impact Weather Potential: Minimal. Some light rain/snow mix possible by early morning. Pattern Synopsis/Forecast: Afternoon analysis reveals low amplitude short-wave ridging building through the western Great Lakes. Surface high pressure and dry air stretches from Canada down through the Great Lakes. Fairly deep daytime mixing (near 750 MB per RAP soundings) has crashed surface dewpoints down through the teens today producing RH values in the 15 to 25 percent range at many locations. Also, there is a little more gustiness out there than anticipated owing to the deep mixing. Meanwhile, lots of sunshine out there save for some heating of the day CU across eastern upper and parts of northeast lower MI as well as some high thin cloud cover also drifting through. Upstream, slow move short-wave and surface low pressure is moving into the Northern Plains. Warm advection forced band of cloud cover and spotty precip have been steadily making their way into the Midwest. Mainly quiet conditions anticipated for the forecast area tonight with steadily increasing high cloud cover from the upstream system. Light winds/low dewpoints should allow temperatures to fall back off through the 30s and possibly into the upper 20s, although temperature drop will be moderated by the increasing high clouds and eventually an increasing SE wind toward morning. Meanwhile, latest guidance trends suggest the aformentioned warm advection band of light precip will slide up into the region during the overnight hours. But...forecast soundings suggest otherwise, with lots of dry air hanging on below 8-10K feet until at least Monday morning. Plan is to keep the forecast dry all the way through the tonight period then begin to bring some light rain/snow mixed precip into the region after 6 am. && .SHORT TERM...(Monday through Wednesday) Issued at 320 PM EDT Sun Apr 28 2019 ...Unsettled and Cool... High Impact Weather Potential...Low. Primary Forecast Concerns...Precipitation type Monday. Monday...A couple of weak disturbances centered to our north and south move through the region Monday into Monday evening. Not a whole lot of forcing in evidence and moisture looks like it`s barely deep enough to make it up to -10 C. In addition, 850 mb temperatures remain cool, generally on the order of -1 to -4 C. This all adds up to lots of question marks as far as pops and precipitation type. At this point will go with chance pops for much of the morning (as model soundings/cross sections take a while to moisten up). Pops should then increase to between likely and categorical from southwest to northeast (highest pops across the south). Surface temperatures will be above freezing so precipitation type will depend upon the depth of the melting layer which looks marginal. Could see a little snow, rain or a mix of the two. Little to no snow accumulation is expected because of the time of the day and likely lack of heavy precipitation, though can not rule out a little slushy accumulation on grassy surfaces in some areas. Highs generally in the upper 30s to lower 40s which should occur in the morning. Monday night...Any remaining precipitation should diminish from southwest to northeast leaving mainly cloudy skies. Temperatures not falling a whole lot with lows in the lower and mid 30s. Tuesday into Wednesday...A slow moving area of low pressure moves up from our southwest likely bringing another round of wet weather to northern Michigan Tuesday afternoon into Wednesday. Precipitation should fall mainly as rain, though there could be a little snow across eastern upper Tuesday night. Remaining unseasonably cool with highs only ranging from the upper 40s to mid 50s. Lows Tuesday night in the mid 30s to lower 40s. .LONG TERM...(Wednesday night through Sunday) Issued at 320 PM EDT Sun Apr 28 2019 ...Remaining Cool... High Impact Weather Potential: Very low. The active and overall cool weather pattern is expected to continue through at least next weekend. There will be chances for rain showers Thursday and again Sunday. Friday and Saturday may turn out rain free but wouldn`t totally count on that yet. Temperatures are expected to remain at least a few degrees below average for early May. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1133 PM EDT Sun Apr 28 2019 VFR tonight. MVFR at times by Monday afternoon in rain or mixed rain/snow. High pressure is getting dislodged to the eat of the region. High clouds are increasing ahead of our next system, still back in the plains states. Low pressure will advance toward southern Lake MI by Sunday afternoon. Clouds will continue to thicken tonight, and precipitation will gradually push into the area Monday from sw to ne. This will be mostly rain at the TAF sites, but could mix with snow at times, especially at APN/PLN. Cigs will eventually lower to MVFR, toward midday at MBL and in the afternoon at the other sites. Light winds tonight. E to se winds Monday, a bit gusty at times. && .MARINE... Issued at 320 PM EDT Sun Apr 28 2019 Another weather system will move through the Great Lakes region Monday and Tuesday. Southeast winds will increase ahead of this system and may bring some low end small craft advisory conditions to parts of the northern Great Lakes for Monday into Monday night. Winds/waves diminish for later Monday night into Tuesday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...SMALL CRAFT ADVISORY from 9 AM to 5 PM EDT Monday for LMZ345-346. LS...NONE. && $$ UPDATE...JZ NEAR TERM...BA SHORT TERM...AS LONG TERM...AS AVIATION...JZ MARINE...BA
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
100 PM PDT Sun Apr 28 2019 .SYNOPSIS... Upper level low will bring slight chance of showers and thunderstorms this afternoon and again tomorrow. Cooling trend with the passage of this system will take the forecast area to seasonable temperatures starting tomorrow through Wednesday, with dry weather occuring at least through Friday. && .DISCUSSION... An upper level low centered near 30N and 125W is approaching the California coastline this afternoon. This low will be responsible for falling temperatures across the forecast area as well as a chance for thunderstorms today and tomorrow across the Kern County Mountains and the Sierra Nevada as it approaches land. For this afternoon, the best chance of thunderstorms looks to be over the Kern County Mtns. just west of the Grapevine area where CU has been forming for the last hour or two. If a cell forms, it may drift north over southern Kern County as indicated by the 18z HRRR model. A thunderstorm or two is also conceivable over the Sierra Nevada this afternoon Fresno County and southward. As this system moves inland, some wrap around moisture will find itself in our CWA, and will bring another chance of showers and thunderstorms over the mountain crests. A storm or two could also make its way into the Mojave Desert by tomorrow afternoon. Rainfall totals from this system overall are not very impressive, but it should be noted that any thunderstorm that forms could produce runoff into already swift and high running rivers. As a reminder, a Flood Watch is in effect for the Southern Sierra Nevada, adjacent foothills, and Kern County Mountains from the snowmelt that has been occuring over the last few days. Tomorrow will also feature high temperatures around 80 degrees in the lowest elevations of the SJ Valley, which is about average for the forecast area this time of the year. Along with the passage of this system will also be an uptick in wind gusts through the Kern County Mountains and Deserts, but they look to remain below advisory level at this time. Tuesday, medium range models have a disturbance progged to arrive into the forecast area from the north/northwest -- an "inside slider". Currently, light precipitation is forecast to occur in the Sierra Nevada with this system. However, this system will again increase winds throughout Kern County by evening. Zonal flow looks to dominate over the forecast area on Wednesday, and brief ridging may occur on Thursday, bringing max T`s back up into the upper 80s. Friday and onward has very low forecaster confidence as there is a massive spread among the deterministic GFS and ECM. EPS ensemble mean shows a Rex Block forming in the Eastern Pacific, which is likely confusing model`s solutions for the next ULL that may impact the forecast area later this weekend. && .AVIATION... VFR conditions will prevail at MCE, MER, FAT, VIS, and BFL through at least the next 24 hours. MVFR or lower conditions are conceivable at BFL after 12z. This possibility is not great enough to include in the BFL terminal forecast at this time. Widely separated showers and isolated thunderstorms are expected in Kern County and the Southern Sierra Nevada this afternoon through Monday morning. && .AIR QUALITY ISSUES... None. && .CERTAINTY... The level of certainty for days 1 and 2 is medium. The level of certainty for days 3 through 7 is low. Certainty levels include low...medium...and high. Please visit for additional information an/or to provide feedback. && .HNX Watches/Warnings/Advisories... Flood Watch through Monday morning CAZ190>196. && $$ public...Bollenbacher avn/fw...BS synopsis...Bollenbacher
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1105 PM CDT Sun Apr 28 2019 .SHORT TERM...(This evening through Monday night) Issued at 348 PM CDT Sun Apr 28 2019 Early this afternoon, the center of a strong storm system was over north central Montana. Mid-high level cloudiness continued to stream across the Upper Midwest, but low level moisture has remained dry. This has kept any precipitation in the form of virga or sprinkles this afternoon. This dry layer will also lead to a slower onset of the precipitation overnight, with the bulk of the precipitation across central/west central Minnesota before midnight, which quickly moves across eastern Minnesota, and into west central Wisconsin after midnight. It should also be a short duration of the precipitation as most of the energy with this system stays across northern Minnesota, west central Wisconsin Monday morning. However, wrap around moisture associated with the upper low, will bring some sprinkles or light showers across the area by late morning/early afternoon. This is more diurnally driven, anything that develops should quickly dissipate by the late afternoon. The next system will quickly wrap up over the four corners region of the U.S. and move northeast across the Rockies, and into the Plains by late Monday night, and early Tuesday. Some light precipitation is possible toward sunrise Tuesday as this system gets closer. Temperatures should be warm enough to keep the bulk of the precipitation in the form of rain vs. snow. However, I can`t rule out some light snow in west central Wisconsin, and portions of central/east central Minnesota late tonight as temperatures fall to around 35 degrees. .LONG TERM...(Tuesday through Sunday) Issued at 348 PM CDT Sun Apr 28 2019 The long term looks active and cool with several systems being steered across the northern U.S. The first will be Tuesday and Tuesday night with the surface low tracking across the Mid Mississippi Valley. The heaviest rain will be located near the quasi-stationary front along the low`s track, but a wave of light rain should track northeast on the system`s northwest periphery across the local area. Beyond midweek or so, model consistency takes a dive with the temporal and spatial details of each system, so the forecast is littered with low chance PoPs. However, another wave is progged to head through sometime around Wednesday night, Friday/Friday night, and again Saturday/Saturday night. With all the clouds and predominantly northerly flow through the period, temperatures will remain 10-15 degrees below normal through next weekend. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1105 PM CDT Sun Apr 28 2019 Main change we`ve seen since the 00z TAFs is that hi-res models are indicating there being two enhanced areas of precip. One from western into central MN and the other southeast MN into central WI. This means very little precip will likely be experienced in between at RWF/MKT/MSP/RNH. As precip/virga has spread across the area, we have seen cigs respond, though models are starting to keep cigs primarily MVFR, so did raise heights some. Also still a bit of an unknown is how skies will react as a mid-level dry slot moves in behind the inverted surface trough. HRRR is pretty aggressive with showing expansive clearing across the area by the afternoon, though there is also the indication we could see some dirunal showers develop within the steep lapse rates of the dry slot. Was not quite that aggressive, but did move up return to VFR in the afternoon with the 6z TAFs. KMSP...MSP looks to shoot between the better forcing to the north and moisture to the south. Even at 4z, the temp/dewp spread was almost 30 degrees, so continued to push back precip arrival. With the better moisture sliding off to our east, probability for seeing IFR cigs is decreasing. /OUTLOOK FOR KMSP/ Tue...MVFR. Aftn -RA likely. Winds E 10-15 kts. Wed...MVFR. Winds NE 5-10kts. Thu...MVFR bcmg VFR. Winds NW 10G20kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ SHORT TERM...JLT LONG TERM...BORGHOFF AVIATION...MPG
Area Forecast Discussion
National Weather Service Portland OR
855 PM PDT Sun Apr 28 2019 EVENING UPDATE: for aviation section. .SYNOPSIS...North flow aloft will continue over the area through midweek. Weak disturbances within the flow will bring a small threat of late afternoon and evening showers to the South Washington Cascades through Tuesday. Dry weather with seasonal temperatures then continue through the end of the week. && .SHORT TERM...Tonight through Wednesday...Water vapor imagery early this afternoon showed a 500 mb ridge axis along 130W extending into the Gulf of Alaska. Meanwhile, A closed low was located off the Southern California coast and another low was drifting east across the Upper Midwest. The end result for the Pacific Northwest is north flow aloft with several short-wave features within the flow. Water vapor showed one such short-wave exiting SE Oregon at 20Z. In the low levels, north to northeast flow is resulting in a rather dry air mass, with early afternoon dew points in the 20s to mid 30s across most inland areas. Cascade locations had dew points in the teens. Higher resolution models like the HRRR and NamNest indicate the potential for isolated shower activity over the South Washington Cascades through early evening. At 20Z GOES-17 imagery showed stratocumulus/cumulus developing over around Mt. Adams. A surface thermal trough will remain over the interior valleys to the coast tonight. Minimal to no cloud cover and low dew points will lead to another cool night, but not quite as cold as this morning. Expect some frost areas, but mainly confined to the Cascade valleys. But, cannot rule out localized near-freezing temperatures in the usual cold inland valley areas, such as Banks, Forest Grove, Hillsboro and around Eugene. Model soundings suggest a low-level inversion, which will allow the Coast Range and Cascade lower slopes, as well as the Willapa Hills, to see a few degrees of warming tonight. The 500 mb north flow pattern continues through the short term with additional short-waves within the flow. The NAM shows another such impulse tonight, but due to the over-land trajectory not expecting any precip. A stronger short-wave drops south Mon afternoon and evening, for a better chance of showers over the South Washington Cascades and a small threat over the North Oregon Coast Range. The north-to-south surface gradients continue Mon afternoon for breezy north wind through the Willamette Valley and along the coast. By 12Z Tue the surface thermal trough will extend from the Willamette Valley to the coast, but then shift east Tue afternoon. Despite the shift to onshore low-level flow models do not show much in the way of low clouds, even along the coast. The 975 mb NAM RH remains rather dry 12Z Wed. Thus, went a little lower than guidance on Wed min temps. Model 850 mb temps show minimal cooling Wed compared to Tue. This translates to a near persistence forecast, although the low-level onshore flow should result in a little cooling to the coastal areas, west slopes of the Coast Range and the SW Washington coastal interior. Weishaar .LONG TERM...Wednesday night through Sunday: A generally dry start to the extended as the PacNW is situated under a NNW flow aloft from a broad upper low centered over the Yukon Territories and extending south over the central CONUS. Further west, there is a rex block with the attendant upper low centered near 35N/145W. That far western position will allow for a weak short-wave to drop southeast along the flow Wednesday night and Thursday. Main impact will be increased clouds and slightly cooler temperatures although most of the medium range models show very light qpf across portions of the CWA. Would be surprised at this point if anything measurable reaches the ground. Have gone with sprinkles for now. The rex block moves closer through the weekend with flow becoming increasingly more zonal over the top of us. May also get some periods of sprinkles/drizzle Friday and Saturday, but am even less excited for those two days than the first round. For Sunday, models and their respective ensembles are not quite sure on how to handle the cut-off low portion of the rex pattern. GFS and the majority of its ensemble members absorb the low into a deepening upper trough crossing toward the PacNW from the northern stream. The ECMWF is rather insistent on maintaining a cut off low off the southern California coast. The former would bring a minimal chance of rain by Sunday afternoon with better chances overnight into Monday, while the latter sees some light QPF across the north earlier on Sunday. Decided go give a 20% PoP to many areas, although Sunday could largely end up having the same minimal rain threat as the prior days. Main impact will again bee cooler temperatures with increased cloud cover. /JBonk && .AVIATION...Cool and dry air mass over the region tonight and Mon, with dry northerly flow aloft. This will maintain mostly clear skies again tonight through Monday. KPDX AND APPROACHES...No adverse weather impacts expected, with clear skies under high pres and light northerly flow. /Rockey && .MARINE...High pressure over the northeast Pacific and a thermal trough along the south Oregon coast are causing gusty northerly winds to 30 kt this afternoon and evening. This pattern starts to weaken as the thermal trough weakens tonight allowing winds to decrease a little, but winds will continue to gust up to 20 to 25 kt overnight tonight into Monday. Monday this pattern finally starts to really break down as the thermal trough weakens significantly. This means winds should drop below 20 kt by Tuesday morning, probably Monday night north of Cascade Head. High pressure continues to dominate over the northeast Pacific through all of next week, but once winds drop below 20 kt Monday night or Tuesday, conditions stay relatively benign with winds staying generally out of the north to northwest and staying mostly below 20 kt through the end of next week. Seas continue to stay steep this afternoon and evening, but will start to subside Monday morning with the weakening winds. Once seas drop to 5 to 6 feet on Monday, seas should stay around 4 to 6 feet through the end of next week. -McCoy && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory for winds from 4 PM this afternoon to 7 AM PDT Monday for Waters from Cape Shoalwater WA to Cascade Head OR from 10 to 60 NM. Small Craft Advisory for hazardous seas until 4 AM PDT Monday for Coastal Waters from Cape Shoalwater WA to Florence OR out 60 NM. Small Craft Advisory for winds until 4 AM PDT Tuesday for Waters from Cascade Head to Florence OR from 10 to 60 NM. Small Craft Advisory for winds from 4 PM this afternoon to midnight PDT tonight for Coastal waters from Cape Shoalwater WA to Cascade Head OR out 10 NM. Small Craft Advisory for winds from noon today to 4 AM PDT Monday for Coastal waters from Cascade Head to Florence OR out 10 NM. && $$ Interact with us via social media: This discussion is for Northwest Oregon and Southwest Washington from the Cascade crest to 60 nautical miles offshore. This area is commonly referred to as the forecast area.
Area Forecast Discussion
National Weather Service San Diego CA
826 PM PDT Sun Apr 28 2019 .SYNOPSIS... Low pressure will move across Southern California late tonight through Monday. Maintaining gusty westerly winds over the mountains and deserts, and deepening the marine layer onto the coastal mountain slopes. There is even a chance for isolated thunderstorms, but most of the precipitation is expected to be light. Some drizzle will be possible along and west of the mountains on Tuesday as well, due to the very deep marine layer that will be in place. Dry, with modest warming Wednesday through Friday. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... At 8 PM PDT...Radar indicated showers and isolated thunderstorms tracking NNE over the inner coastal waters. Most of this activity was weak and moving rapidly. A more solid line of thunderstorms was farther south off the Baja CA Coast. This was also lifting NNE and may track into the SGX forecast area later this evening. Elsewhere, skies were partly cloudy with wave clouds over the mountains. The 00Z Miramar sounding was still quite stable with a 7C inversion base just under 2000 FT MSL. The PW had increased to 0.87 inch due to a big jump in moisture above 12K FT, but a dry layer was indicated below to the marine inversion. The sfc pressure gradient KSAN to the deserts was still 7-8 MBS but the strongest SW winds were mostly in the 25-30 MPH range at last report. The local WRFEMS shows winds increasing overnight mts/deserts, so a Wind Advisory is in place for late tonight through late Monday evening with gusts to around 50 MPH possible. Most areas should see some rain or sprinkles overnight, and given the deepening marine layer forecast, this may get more widespread into Tue morning along and west of the mts. A thunderstorm or two still looks possible into the deserts through tomorrow afternoon, with the biggest threat being lightning. Rainfall amounts overall are expected to be light. The forecast was already updated late this afternoon to increase POPS and QPF. No other forecast changes this evening. From previous discussion... ...SHORT TERM (This Afternoon through Tuesday)... Water Vapor imagery shows an upper low situated some 500 miles off the coast of northern Baja. This feature will move east northeast and over Southern California mid-late morning on Monday before moving east during the afternoon. Thunderstorms were added to the forecast for the San Gabriels, San Bernardinos, and San Jacintos for this afternoon and that looks good as there is some CAPE across these areas this afternoon. Then, tonight through Monday (especially morning), there is a chance of showers across all areas as the upper low moves overhead. CAPE is low (cools aloft but it`s much cooler at the surface), so thunderstorms are not a slam dunk, but there is a slight chance. This could turn into more of a drizzle event more than anything, but with steadier light rain along the southwest coastal slopes. Moisture isn`t all that high, so rainfall amounts will be light. Upslope flow will lead to light rain along the southwest facing slopes of the San Bernardinos with max amounts forecast to be 0.50-1.00 inches along the slopes west of Crestline. Elsewhere, amounts will average 0.10" or less, but isolated locales could receive 0.25-0.50". WRF and HRRR show cells with rates of only 0.10-0.20"/hr tonight-Monday. So no significant impacts are expected from this upper low. It will move east during the afternoon on Monday with showers ending during the evening. West-Southwest winds will strengthen with strong winds expected along the desert mountain slopes and into parts of the lower deserts, particularly the San Diego County deserts. Have issued a Wind Advisory for all lower deserts effective 11 PM tonight through 11 PM Monday. Much cooler conditions as onshore flow strengthens will be felt on Monday with cool weather continuing on Tuesday, but Monday will be the coolest day for most locales before temps slowly moderate as heights slowly rise. Added this evening... The various model runs diverge into next weekend with the track of another closed low that develops under the mean ridge over the EastPac. The ECMWF solution keeps it offshore, while a number of GFS Ensemble members move it along, impacting SoCal at some point over the weekend. Forecaster confidence falters here regarding to what degree it may influence our weather, but for now, slight chance POPS are in the forecast by late Sunday. Also, onshore flow and some marine influence is expected to prevail, keeping temperatures close to the seasonal average, along with areas of night and morning low clouds and fog. The marine layer will become gradually shallower with night and morning low clouds and fog not spreading as far into the valleys. The marine layer will then deepen into next weekend as the next low pressure system arrives. && .AVIATION... 290250Z...Coast/Valleys...BKN low clouds moving ashore this evening with bases 1500-2000 ft MSL and will continue to spread to inland valleys as the evening progresses. -SHRA and isolated TSRA are possible in all areas this evening into the day on Monday. Reduced vis 3-5 SM at times are expected in some areas, with BKN-OVC bases lowering to 1000-1500 ft MSL during showers. Coastal slopes may become obscured in low clouds. Mountains/Deserts...SCT-BKN high clouds tonight with bases AOA 10K ft MSL. -SHRA and isolated -TSRA are possible this afternoon into Monday, mainly over the mountains. Areas of west winds 15-25 knots with gusts to 45 knots are possible overnight on the desert mountain slopes and at times onto the desert floor, along with moderate up/downdrafts and local LLWS. Highest wind gusts will be Monday morning. && .MARINE... Areas of showers and a slight chance of thunderstorms tonight through Monday evening. A Marine Weather Statement has been issued for the threat. No other hazardous marine conditions are expected through Thursday. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory until 11 PM PDT Monday for Coachella Valley-San Diego County Deserts-San Gorgonio Pass Near Banning. PZ...NONE. && $$ PUBLIC...10/Gregoria AVIATION/MARINE...APR
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Monday) Issued at 336 PM CDT Sun Apr 28 2019 Main challenges through Monday afternoon remain to be precipitation chances and intensities. Zonal flow over old frontal boundary, now rather well mixed out over the southern Plains, leading to regions of enhanced moisture return, with scattered high-based convection in recent hours in east-central Kansas and other elevated storms in central Oklahoma. Surface dewpoints above 40 remain the exception in the local area, though gusty south winds were allowing values to return to the middle 50s from southwest Kansas into northern portions of Oklahoma as surface low pressure deepens in eastern Colorado ahead of modest upper wave. A stronger upper wave over eastern Montana has allowed a cold front to surface southeast into northwest Nebraska early this afternoon. Evolution of next several hours will be key to the late evening and overnight period with the greater concern exists for the local area as the weak upper wave translates over Kansas and low-level moisture surges north ahead of the approaching cold front. Short-range guidance has overall struggled with ongoing elevated convection but has been rather consistent with rapid destabilization taking place as moisture continues north. Steady to rising temps are quite possible as a 50 knot low-level jet develops and may keep boundary layer CIN quite low as storms approach from the west. 19Z RAP brings ML CAPE to around 1000 J/kg with CIN less than 100 J/kg with rather strong effective shear. This setup keeps the tornado threat non-zero but expect hail and winds the be the main concerns. Low-level convergence and upper flow orientations continue to suggest training storm potential with precipitable water values in the 1-1.5" range. Even the current precip has not brought much wetting rain to the area over the past few weeks and the flash flood guidance values of a few inches are legitimate, but given the weak synoptic forcing/training potential, will keep the Flood Watch going as-is. The northern cold front should being to push through the area late tonight and bring precip to an end for the bulk of the area by early Monday morning but have kept some chances in far southeast areas with the boundary not far away under southwest flow aloft. .LONG TERM...(Monday night through Sunday) Issued at 336 PM CDT Sun Apr 28 2019 Biggest concern in the long-range portion of the forecast package will be a chance for severe storms for the southeastern CWA, and a flooding potential on Tuesday with a round of moderate to heavy rain. A surface front near the I-44 corridor in MO will begin moving back to the north as a warm front Monday night. Broad scale lifting in the mid levels will occur over the area into Tuesday in response to an embedded upper shortwave trough moving through the flow and over the region. As a result, a widespread batch of rain is looking likely early Tuesday over all of northeastern KS. Rain intensity and thunderstorm coverage is expected to increase into Tuesday afternoon, especially in east-central KS as a warmer and more moist air mass arrives in eastern KS. Models are in a little better agreement today with the northward extent of the warm front with most bringing it to near or just south of TOP by 21Z Tuesday. CIN will erode and surface based CAPE will increase during the afternoon, especially south of a line from Lawrence to Emporia, which will be the most likely area to experience strong to severe thunderstorms Tuesday afternoon. The NAM and GFS are currently both indicating the possibility of near 2000 J/kg of CAPE developing over east-central KS with very little, if any, inhibition. Meanwhile, 0- 6km bulk shear values could approach 50-55 kts. Will be monitoring this area and timeframe for the possibility of severe weather. Additionally, moderate to heavy rainfall, especially that associated with stronger thunderstorm activity, will add more concern about flooding following previous rounds of rain and the resultant moistening of soils. The front will pass back to the south Tuesday night taking convection with it and allowing for quieter conditions over the CWA into Wednesday. Rain may not be done with the area just yet, however, as a final round of mainly lighter rain will be possible early Thursday before a surface ridge of high pressure builds over the area Thursday afternoon. The ridge will bring in a drier air mass along with a return to some sunshine. Long range models are then hinting at a few weak fronts associated with some northern stream systems moving through the area from Friday through the weekend. Will monitor for rain/storm chances during that timeframe as we get closer. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 640 PM CDT Sun Apr 28 2019 For the 00z TAFs, a complex of showers and thunderstorms are expected to impact the TAF sites late this evening through the overnight hours before diminishing Monday morning, with low-end MVFR cigs likely and possibly even dropping to IFR. As a 45-55kt LLJ tracks over the area this evening, anticipate LLWS concerns. Winds should remain gusty near 20kts through much of the TAF period, with winds backing from southeast to north with the passage of a cold front. && .TOP WATCHES/WARNINGS/ADVISORIES... Flood Watch from 10 PM CDT this evening through Monday morning for KSZ021>024-034>039. && $$ SHORT TERM...65 LONG TERM...Teefey AVIATION...Hennecke
Area Forecast Discussion
National Weather Service Tulsa OK
829 PM CDT Sun Apr 28 2019 .DISCUSSION... What a difference over the course of the day today. Much of the area started off cool and dry this morning and now with the warm front lifting north thru the region, warm and humid air has returned. Expect a much warmer night tonight compared to last night. Evening PoPs have been removed as the high based activity from the afternoon has vaporized. Focus then turns to our N and W across KS tonight. While most CAMs and the global models suggest a busy night ahead across KS, these same models keep the convection north of the border tonight. The 700mb warm pool (temps 10C or higher) expands north and east tonight across OK...increasing confidence in the latter solutions. Based on the majority of data and the warming mid lvls the plan is to keep the going forecast of lower end PoPs near the KS border aft 06Z. Lacy && .PREV DISCUSSION... /Issued 646 PM CDT Sun Apr 28 2019/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. Scattered to broken mid and high clouds along with breezy southerly winds are expected overnight for the CWA behind a warm front lifting into Kansas. The exception to the winds will be KFSM where a more easterly direction is forecast to return overnight. During the day Monday...increasing low/mid clouds are forecast as the boundary pushes back into Northeast Oklahoma and stall near Interstate 44. Near the boundary and north...MVFR ceilings and winds between west and north will be possible through the afternoon hours along with chances for showers and thunderstorms. For now will carry VCSH and Prob30 for TSRA for Northeast Oklahoma TAF sites. For the rest of the CWA Monday...increasing mid clouds and breezy southerly winds are forecast. PREV DISCUSSION... /Issued 543 PM CDT Sun Apr 28 2019/ UPDATE... Some tweaks have been made to the evening forecast, refining PoPs per latest obs and short term hi-res model trends. See discussion below. DISCUSSION... PoPs have been shaved off to the west of the current band of high based showers and isolated storms. This activity was focused on the leading edge of waa/isentropic lift on the 310K surface. This lift will be focusing up toward the MO Ozarks toward and after 00z, with some evidence of this with recent storm development just north of the KS border in far SE KS. Both the HRRR and experimental HRRR suggest a busy night ahead across KS, with an isolated supercell or two tracking east across southern KS tonight with sig severe potential. This activity should stay north of the border tonight. The current forecast has some low PoPs up near the KS border late tonight and will leave those alone for now given some uncertainty in other CAM solutions. Lacy && .PRELIMINARY POINT TEMPS/POPS... TUL 64 79 64 76 / 10 40 60 80 FSM 61 80 65 81 / 10 10 30 60 MLC 64 79 66 78 / 10 20 30 70 BVO 64 76 61 75 / 30 40 70 80 FYV 61 76 63 75 / 10 30 30 70 BYV 59 77 62 78 / 10 30 30 60 MKO 63 78 64 77 / 10 30 40 70 MIO 62 76 62 75 / 30 40 60 70 F10 64 79 65 76 / 10 30 40 70 HHW 61 78 67 79 / 0 10 30 70 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...None. AR...None. && $$ LONG TERM....99