Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/13/20

Area Forecast Discussion
National Weather Service Caribou ME
916 PM EDT Tue May 12 2020 .SYNOPSIS... A low pressure system will continue to exit across the Maritimes overnight. High pressure will build toward the region Wednesday through Thursday. Low pressure will approach on Friday then move east of the region Saturday followed by high pressure for Sunday. Another low from the lower great lakes will approach on Monday. && .NEAR TERM /THROUGH WEDNESDAY/... 9:16 pm update: Latest radar returns indicate that there are still a few snow showers and flurries in parts of northern and eastern Aroostook County. Flurries could linger till past midnight in far eastern Aroostook County. Otherwise, is is currently mostly cloudy across the northern half of the FA and clear to partly cloudy to the south. The clouds in the north will likely begin to break up more toward morning. Temperatures are already in the 30s in most areas Downeast and the freeze headlines look good. Made some minor adjustments for the remainder of the night based on the latest satellite pictures, radar returns, and observations; but overall the changes were relatively minor. Previous discussion: It was an interesting day across northern Maine with the coldest early afternoon temperatures ever recorded in Caribou as the thermometer fell to the upper 20s thanks to low cloud cover, precipitation, and strong cold advection of a very anomalously cold air mass over central Quebec. Due to loss of cloud ice, freezing rain also fell briefly and created a glaze on elevated surfaces. Water vapor satellite this afternoon shows two distinct upper level lows, one over the Canadian Maritimes and another entering southern Quebec. Just ahead of this, a weak theta-e ridge is noted and has led to a slight moderation of temperatures over the past hour or so across northern Maine. As the second upper low moves across the forecast area this evening, a band of snow will briefly form again over eastern Aroostook County as noted on the HRRR and hinted at on the RGEM. Accumulation will be limited to an inch or less. Any lingering precipitation should end after midnight as the second 500mb vorticity maxima moves off to the east and drier air advects in aloft. Temperatures will fall below freezing across nearly the entire forecast area, except perhaps along the immediate coast. A rare advection driven freeze warning has been issued for portions of Downeast Maine where the growing season has begun. A light to moderate breeze and dry advection should keep widespread frost from forming. Skies will clear out for tomorrow with 850mb temperatures of -5 to -10C limiting warming despite the strong May sun. Late afternoon stratocumulus development is also possible across northern Maine, so current sky cover forecasts are on the optimistic side there for the late afternoon. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... Wed ngt will likely be the last unseasonably cold ngt as, finally, the last of historic arctic air masses that has dominated the Rgn retreats NE toward the Nrn Can Maritimes. This will allow for additional sig recovery of hi temps on Thu under msly sunny skies and contd breezy conditions with mixing of stronger winds from alf from late morning thru mid aftn. Winds will quickly diminish Thu eve as the sfc ridge crosses the FA, but increasing hi/mid cldnss from low pres movg E from the midwest/lower great lks. Shwrs/rn from this system will begin ovr Wrn areas by Fri morn, but will likely hold off ovr Nrn/Ern areas til Fri aftn or even evening. Ovrgnt lows will be milder Thu ngt, with hi temps Fri capped earlier in the day by cld cvr and rnfl arrival. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Rain will taper off to sct shwrs and then end from late Fri ngt into Sat morn across the FA. With the dynamics of low weakening somewhat as it crosses the FA, it appears best rnfl will be across Cntrl and Downeast areas with a quarter to half inch of event rnfl indicated there attm, to as little as arnd a tenth across the far N. Subsequently, highest PoPs in the categorical range were weighted ovr Cntrl and Downeast areas. By Sat aftn, skies look to at least partially clr across the FA with with warmer, even slightly abv normal, hi temps with the air mass behind the low warmer than the one ahead of it. Sat ngt and Sun morn also look fair attm. Clds will be on the increase by Sun aftn with shwrs/rn a good bet for later Sun into Mon eve as another low approaches from the great lks and tracks ewrd just S of the FA. Behind this low, the consensus of long range models indicates that Tue and Wed look to be fair, with potentially warmer conditions by Wed. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: VFR Downeast. Mainly VFR from KHUL north with brief MVFR visibility possible in any remaining snow showers late this evening, then VFR late tonight and Wed. VFR at the Downeast terminals. NW wind gusts up to 25 knots are expected during the day Wed. SHORT TO LONG TERM: Wed Ngt - Thu Ngt...VFR all TAF sites. Brisk NW winds durg the day Thu. Fri - Fri Ngt...MVFR-IFR clgs/vsbys all TAF sites in rn or rn shwrs. Lgt winds. Sat - Sun...Mainly VFR all TAF sites with lgt winds. && .MARINE... NEAR TERM: While a brief break in small craft conditions is anticipated this evening, the small craft advisory has been extended until Wednesday afternoon to account for increasing wind gusts to around 25 knots again after midnight. Seas over the outer waters of 3 to 5 feet will also continue overnight and into Wednesday. Winds and seas diminish below small craft later Wednesday afternoon. SHORT TO LONG TERM: No definitive SCA pds identified for this update, although wind gusts and seas may approach attms. Kept close to blended wv model guidance for fcst wv hts for these ptns of the fcst. Initially wvs will be composed of a SE propagating short fetch pd of 3 to 5 sec and a NW propagating open Atlc background swell Wed ngt and Thu, consolidating to a single northward propagating 6 to 9 sec wv group by Fri, contg into the weekend. && .FIRE WEATHER... Fire concerns will only start becoming a concern for our FA by Wed aftn as breezy winds and lower aftn RHs begin to dry the duff later from recent rains and snows. Relatively low aftn hi temps may also somewhat limit combustion potential from ignition sources Wed aftn A better potential for for fire starts will likely occur on Thursday when breezy NW winds, low aftn RHs, and warmer hi temps further dry out fine fuels. We will coordinate any fire wx products with the State of ME Forest service beginning tomorrow morning based on there assessment of fire danger attm. && .CLIMATE... 0.3" of snow and freezing rain was observed in Caribou, Maine today. This brings our monthly snowfall total to 5.9" and makes it the 3rd snowiest May on record. A total of 151.9" of snow has been observed for the season, which is good enough for 6th place. Weather records in Caribou date back to 1940. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Freeze Warning until 8 AM EDT Wednesday for MEZ015>017-029-030. MARINE...Small Craft Advisory until 2 PM EDT Wednesday for ANZ050>052. && $$ Near Term...CB/MStrauser Short Term...VJN Long Term...VJN Aviation...CB/MStrauser/VJN Marine...CB/MStrauser/VJN Fire Weather...VJN Climate...CB
Area Forecast Discussion
National Weather Service Dodge City KS
605 PM CDT Tue May 12 2020 ...Updated Aviation Discussion... .SHORT TERM...(This evening through Wednesday) Issued at 349 PM CDT Tue May 12 2020 The persistent cool, cloudy, moist airmass will continue across southwest Kansas tonight into Wednesday morning before finally eroding away. Temperatures struggled to get much above the mid 40s mid afternoon on a continued east-southeast wind. Morning light fog and drizzle waned late this morning toward the lunch hour but is expected to redevelop later this evening as low level moist advection just off the surface increases. Another round of elevated showers and thunderstorms are expected to develop across south central Kansas, so we will keep at least some low POPs going across the far eastern counties adjacent NWS ICT forecast area. The HRRR and RAP models are fairly aggressive with dense fog development with a rather large area of model visibility one-quarter mile or less. The incoming swing shift will need to monitor this closely. Wednesday will be quite the wild temperature ride for most -- especially far southwest Kansas. A hot, dry airmass will be replacing the cool, moist airmass over far southwest Kansas, and these areas will likely see afternoon temperatures some 40-degrees warmer than this afternoon! The remnant cool, moist airmass will be slower to erode farther east, and this is where the temperature forecast will get quite tricky. Some of the latest high-resolution model solutions, including WRF-ARW, NAM12, and HRRRv4 show central Kansas stuck in the mid-upper 50s by mid to late afternoon, and should this pan out, it will really limit the spatial extent of boundary layer instability for severe local storms. The latest SWODY2 maintains a 15-percent large hail outlook with 10-percent hatched area for significant hail potential (two-inch diameter or larger). Much of late tomorrow/tomorrow evening`s convective event will be confined to areas south and east of the NWS DDC forecast area, but the latest thinking is that 3 to 5 of our counties stand a decent chance for a severe storm or two (perhaps more if the primary zone for convective initiation shifts farther west). Any severe weather threat should wane by late evening as storms move east, deeper into Kansas and Oklahoma. The remainder of Wednesday Night period looks quiet with south winds remaining in place ahead of another cold front. .LONG TERM...(Wednesday night through Tuesday) Issued at 349 PM CDT Tue May 12 2020 On Thursday, another cold front will push south before slowing down and eventually stalling out somewhere just south of the NWS DDC forecast area. Another severe weather risk will exist along this front, but south of our area across western and central Oklahoma. Post-frontal upslope will develop later in the evening Thursday, and this is also likely to support thunderstorm activity across southeastern Colorado. Any southeastern Co storms in the evening would move into and/or expand across west central and southwest Kansas. In fact, the period from late Thursday Night through late Saturday Night looks convectively-active across the southwest Kansas region as the quasi-stationary front will remained positioned close to the Oklahoma-Kansas border. Fairly vigorous surface-based convection also appears more likely along the boundary, wherever it sets up, late Friday afternoon/evening. Overall, this pattern is a little more reminiscent of early-mid June instead of mid-May given the fairly weakish mid level westerly winds (25 to 30 knots at 500mb) and the absence of a formidable short-wave trough, thus keeping the surface frontal zone quasi-stationary for a prolonged period of time -- which will mainly shift due to various convectively-induced outflows. That being said, a stronger polar front will move across western Kansas late Saturday Night/early Sunday, putting an end to this stormy multi-day period. The ECMWF shows a quite pattern developing with a 590 decameter 500mb ridge forming over New Mexico, nosing into southwest Kansas early next week. It remains to be seen how this will affect the next large scale trough coming into the western CONUS early-mid next week. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 602 PM CDT Tue May 12 2020 LIFR ceilings can be expected overnight as a southeasterly wind at 10knots or less continues across southwest and north central Kansas. Areas of fog and drizzle will also be likely with visibilities of 1/2mile or less being possible at times...mainly from 06z and 14z Wednesday in the Dodge City and Garden City areas. After 14z ceilings and visibilities will improve with MVFR conditions developing by 18z Wednesday. VFR conditions are expected between 18z and 21z Wednesday. Southeast winds at around 10 knots at 12z Wednesday will become more southerly by noon as the wind speeds increase to around 15 knots. && .PRELIMINARY POINT TEMPS/POPS... DDC 44 77 55 81 / 10 20 10 0 GCK 43 85 50 81 / 10 10 10 0 EHA 47 89 52 84 / 0 0 0 0 LBL 45 89 52 84 / 10 10 10 0 HYS 44 73 55 79 / 20 20 20 0 P28 46 72 61 85 / 20 20 20 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Umscheid LONG TERM...Umscheid AVIATION...Burgert
Area Forecast Discussion
National Weather Service Goodland KS
553 PM MDT Tue May 12 2020 .UPDATE... Issued at 553 PM MDT Tue May 12 2020 Some locales are seeing reduction in visibility and have opted for a Dense Fog Advisory issuance for the CWA thru 15z Wednesday. && .SHORT TERM...(This evening through Wednesday night) Issued at 305 PM MDT Tue May 12 2020 Through Tonight: Strengthening SE-SSE upslope flow /low-level warm advection will maintain the shallow cool/moist airmass in place over the Tri-State area through tonight. No well-defined upper level features can can be identified upstream this afternoon. In the absence of focused upper forcing (i.e. DPVA) -- precipitation will likely be confined to periods of drizzle. Fog will likely re-develop after sunset, with dense fog possible late this evening through tonight (similar to last night). Wed-Wed night: The shallow cool/moist airmass will begin to mix- out /recede eastward/ on Wed. Increasingly (albeit broad) cyclonic flow aloft over the Western CONUS /WSW flow atop the Rockies/ and a diurnally enhanced SFC-H85 baroclinic zone (on the western periphery of the receding airmass) will aid in the development of a lee cyclone in eastern Colorado during the day. In the absence of discernible/focused upper forcing, significant uncertainty persists with regard to (1) the timing (and extent to which) the shallow/stable airmass will mix-out/recede and (2) the precise evolution of the lee cyclone. Guidance suggests that the aforementioned airmass will fully mix-out as far east as Hwy 283 (Hill City) by late afternoon. With weak synoptic forcing (predominately confined to low-level convergence invof the aforementioned sfc boundary) and a pronounced /renewed/ elevated mixed layer advecting eastward from the Rockies into the Central Plains -- convective development is far from certain. Simulated reflectivity forecasts via the HRRR and NAM NEST show little or no convective development in Northwest KS late Wed aft/eve. *If* isolated updrafts (1) develop and (2) survive dry-air entrainment ascending through the EML -- thermodynamic/kinematic profiles appear supportive of supercells. Thus, a conditional potential for severe weather will exist during the late afternoon and early evening, mainly northeast of Goodland between 22-02Z. .LONG TERM...(Thursday through Tuesday) Issued at 158 PM MDT Tue May 12 2020 Unsettled weather continues into the long term period. On Thursday, a shortwave passes across the northern Plains with a cold front already through the region. A disturbance moves through the zonal flow, generating chances for showers and storms in the afternoon through overnight hours. Am anticipating storms to develop off the Front Range and track eastward to the region through the evening. At this point, do not see much of a severe threat as we will be post- frontal, but a couple strong storms could occur. Another wave is expected to eject over the Central Plains on Friday, with a round of showers and storms moving into the region from Colorado in the afternoon and crossing the area Friday night. With better moisture filtering into the High Plains and better instability, a few strong to severe storms could develop. Will continue to monitor to pin down more details in the coming days. Chances for showers and storms linger into Saturday as the shortwave passes east of the region. Confidence in precipitation occurring this day is low at this point due to disagreement among guidance with the speed of the disturbance`s exit. A large, upper closed low slowly approaches the west coast on Sunday. Meanwhile, upper ridging builds out ahead and progresses towards the High Plains. As a result, the region will see a change in weather, with dry conditions and warmer temperatures. A slight cooling trend is anticipated Thursday (70s/low 80s) through Saturday (upper 60s/70s). Temperatures warm Sunday (70s), Monday (80s), and Tuesday (low 90s). Low temperatures range in the 40s and 50s through the period. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 530 PM MDT Tue May 12 2020 Through about 14z-16z Wednesday, both terminals will see mainly IFR to LIFR ceilings ranging from OVC003 to OVC008. KMCK will see brief MVFR ceilings around OVC010 thru about 02z before transitioning lower. After about 14z-16z, VFR skies for KGLD, while KMCK will see MVFR near BKN015 before going VFR by 18z. Besides continued lowered ceilings, fog will be the other main wx issue. Thru about 05z-06z Wed, both sites will see 5-6sm. Afterwards 1sm or less, especially for KGLD. 14z-16z will have 2-3sm before going to VFR vsby. Winds for KGLD, SSE around 15-30kts thru 16z, then SW around 10kts. Winds for KMCK, SE 10-20kts thru 16z, then diminishing to 10-15kts. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...Dense Fog Advisory until 9 AM MDT /10 AM CDT/ Wednesday for KSZ001>004-013>016-027>029-041-042. CO...Dense Fog Advisory until 9 AM MDT Wednesday for COZ090>092. NE...Dense Fog Advisory until 9 AM MDT /10 AM CDT/ Wednesday for NEZ079>081. && $$ UPDATE...JN SHORT TERM...VINCENT LONG TERM...JBH AVIATION...JN
Area Forecast Discussion
National Weather Service Green Bay WI
1052 PM CDT Tue May 12 2020 Updated aviation portion for 06Z TAF issuance .SHORT TERM...Tonight and Wednesday Issued at 247 PM CDT Tue May 12 2020 The latest RAP analysis and satellite/radar imagery show surface high pressure centered over the northern Plains to the Ohio Valley. A very dry airmass has resulted in clear skies and low humidity levels between 15 to 25 percent across the region early this afternoon. The northern edge of the return flow is not too far away, and marked by the northern edge of mid-level clouds stretching from Montana to Iowa. As high pressure moves across the region tonight, forecast concerns continue to revolve around low temps and the frost/freeze potential. Tonight...The surface high will quickly move across the region to the eastern Great Lakes by 12z Wednesday. Meanwhile, mid and high clouds will gradually invade from the west after midnight. Ideal radiational cooling conditions will therefore remain present during the evening before clouds start arriving. This should provide enough time for temps to fall into the upper 20s to middle 30s by late tonight. Used the best performing guidance for low temps, then dropped the cold spots down by a degree or two. As a result, will hoist a frost advisory from central to northeast WI. Wednesday...The region will be positioned between high pressure over the east coast and low pressure emerging into the Plains. Deep layer south to southwest flow will continue to push in cloud cover, so will see increasing clouds through the day. The morning continues to look dry though, with more sunshine over far northeast WI than further southwest. Humidity levels will likely approach 25 pct again over far northern WI before rising in the afternoon. As the moisture transport axis shifts east in the afternoon, chances for showers will increase across north- central WI. But the main push of precip will arrive on Wednesday night. Because of gusty southeast winds, temps over far eastern WI will likely cool off in the afternoon after thicker cloud cover arrives. Highs should range from the mid 50s to near 60 at most locations, locally cooler near Lake Michigan. .LONG TERM...Wednesday Night Through Tuesday Issued at 247 PM CDT Tue May 12 2020 Mean flow is forecast to become more zonal or only slightly amplified later this week which would allow more of a Pacific air mass to spread into WI and bring warmer temperatures to the region. There will be a good chance of showers/slight chance of thunderstorms Wednesday night through Thursday as the warmer air arrives, along with a mid-level shortwave trough. A stronger shortwave trough is expected to arrive late Saturday into Sunday morning and bring northeast WI another chance for showers/storms. As a closed upper low hits the West Coast early next week, a downstream upper ridge to develop over the central CONUS with temperatures moving above normal. A broad southwest flow aloft will pull gulf moisture northward into WI ahead of a weak cold front Wednesday night. This moisture transport, coupled with WAA, should bring a round of showers across northeast WI. The atmosphere is only marginally unstable with an elevated LI barely getting to zero over our southernmost counties. Thus, only a slight chance of thunder mainly south of Highway 10. Min temperatures to range from the lower 40s north/ near Lake MI, middle to upper 40s south. The chance for showers/ thunderstorms would continue into Thursday as the cold front moves across WI. However, guidance indicates that heavier precipitation would remain to our south (IA/southern WI/northern IL) in the vicinity of a warm front. Depending on how far north this warm front can get will determine if the northern edge of these heavier rains can reach parts of central/east-central WI. For now, have kept pops at a chance north/likely south and keep the heavy rainfall to our south. Max temperatures Thursday to range from around 60 degrees lakeside, lower 60s north, middle to upper 60s south. As this entire system (warm front/cold front/shortwave trough) shifts east Thursday night, improving conditions will be observed over the region. Look for a decrease in clouds, a light west- northwest wind and min temperatures near normal. This would put readings around 40 degrees far north, upper 40s across east- central WI (slightly cooler near the lake). High pressure to move across the Great Lakes region on Friday, bringing mostly sunny skies and temperatures closer to mid-May values. This translates to readings in the upper 50s near Lake MI, middle 60s to around 70 degrees inland. Clouds are expected to slowly be on the increase Friday night as a new system organizes over the central Plains. A shortwave trough is progged to move into the northern/central Plains on Saturday with a weak surface low to move into the Midwest. Increasing south-southwest winds will begin to not only tap gulf moisture, but also pull the old cold front north as a warm front into central IA/northern IL by 00Z Sunday. Anticipate thickening cloud cover with the leading edge of showers/possible thunderstorms pushing into northeast WI, mainly during the afternoon. Max temperatures Saturday to be in the middle to upper 50s near Lake MI, middle to upper 60s inland. Saturday night simply looks wet as the shortwave trough moves into the Upper Midwest and a cold front enters WI after midnight. Models vary with the strength of the corresponding surface low, but with increasing mid-level forcing and lift from both the cold front/right entrance region of the upper jet, prefer to ramp up pops from the previous forecast. In fact, some of this rain may become locally heavy at times. The showers/storms would continue into Sunday as the cold front/shortwave trough push across WI. A little too early yet to determine whether any of these storms could become strong or severe. Max temperatures for Sunday to be around 60 degrees lakeside, middle 60s to around 70 degrees inland. A ridge of high pressure to quickly advance into the western Great Lakes region Sunday night, thus ending the precipitation and allowing for skies to become partly cloudy. Monday looks like a nice, Spring day with mostly sunny to partly cloudy skies and temperatures warming above normal as an upper ridge builds overhead. Max temperatures to reach the lower 60s near Lake MI, lower to middle 70s inland. The forecast for Monday night/Tuesday is more uncertain depending on the strength of the upper ridge over the region. A stronger ridge would keep any precipitation to our north and west along a quasi-stationary front. A weaker ridge could allow this front to sag south and bring chance pops to at least northern WI. Have followed the consensus solution which only bring a minimal pop to northern WI on Tuesday. We do expect warm and more humid conditions to return by Tuesday with max temperatures in the middle 60s lakeside, middle 70s to around 80 degrees inland. && .AVIATION...for 06Z TAF Issuance Issued at 1052 PM CDT Tue May 12 2020 Continue good flying conditions with VFR skies and cloud cover through Wednesday afternoon. Winds are expected to remain fairly light and variable through the night. Cloud cover will increase and thicken during the day Wednesday with high clouds moving in Wednesday morning and mid clouds developing/moving in Wednesday afternoon. It is possible that a few showers could move into the central WI TAF sites late Wednesday afternoon, but most of the models are keeping the precipitation out of the area until Wednesday evening. As the rain moves into central WI, ceilings will likely drop into the MVFR range. The pressure gradient will also tighten ahead of the next system, allowing gusty southeast winds to develop through the day Wednesday, with some gusts reaching to around 25 mph. As the atmosphere becomes more stable Wednesday evening, some LLWS will likely develop under an inversion. && .GRB WATCHES/WARNINGS/ADVISORIES... Frost Advisory until 8 AM CDT Wednesday for WIZ020-022-030-031- 035>040-045-048>050-073-074. && $$ SHORT TERM.....MPC LONG TERM......Kallas AVIATION.......Cooley
Area Forecast Discussion
National Weather Service Hanford CA
132 PM PDT Tue May 12 2020 .SYNOPSIS... Storm system continues to impact Central California today by bringing cooler temperatures into the San Joaquin Valley and strong winds through Kern County. Below average temperatures across the forecast area along with periods of gusty winds in Kern County will persist for the next few days. Brief warmup later in the week, followed by another storm system that will impact the forecast area starting next Sunday. && .DISCUSSION... Scattered showers passed through the San Joaquin Valley this morning as a trough of low pressure slowly approaches the West Coast. Fort Ord profiler reveals a marine layer close to 3,000 feet as of of this writing, which reflects the cool, onshore flow we are receiving today. Afternoon highs today will generally be in the mid to upper 70s across the forecast area, which is several degrees below average. The main impact this storm system will bring to the forecast area this afternoon though early tomorrow morning is strong winds through Kern County. HRRR analysis and short range guidance shows a significant pressure gradient forming across the Tehachapi Mountains through this afternoon, capable of producing wind gusts near 60 mph. Therefore, a High Wind Warning has been issued through 5 AM Wednesday through and just below the Tehachapi Mountain passes, as well as the Mojave Desert in Kern County. Another burst of shortwave energy looks to pass through the main trough tomorrow afternoon, which will likely lead to another round of gusty winds in the Tehachapi Mountains/passes and Mojave Desert. Otherwise, expect another day of cooler than average temperatures across the forecast area. Shortwave ridging starts to build late on Thursday, which will mark the beginning of a short-lived warming trend. Near normal afternoon high temperatures can be expected Friday in the low to mid 80s. Upper 80s across the San Joaquin Valley can be expected Saturday, which will be a few degrees above normal for mid May. Model confidence is increasing that another trough of low pressure will near the California Coast by Sunday. This will re-introduce chances of precip (likely light) across the forecast area, cooler temps, and strong winds in the usual wind-prone areas. More specific details of upcoming impacts from this next storm will be clarified in later forecast packages. && .AVIATION... Occasional wind gusts around 50 knots are possible over the ridges and through and below the Kern County mountain passes through 12Z Wednesday. VFR conditions will otherwise prevail across the Central CA interior for the next 24 hours. && .AIR QUALITY ISSUES... None. && .CERTAINTY... The level of certainty for days 1 and 2 is high. The level of certainty for days 3 through 7 is medium. Certainty levels include low...medium...and high. Please visit for additional information an/or to provide feedback. && .HNX WATCHES/WARNINGS/ADVISORIES... High Wind Warning until 5 AM PDT Wednesday for CAZ196-198-199. && $$ public...Bollenbacher aviation....Bollenbacher
Area Forecast Discussion
National Weather Service Wichita KS
1002 PM CDT Tue May 12 2020 ...Evening Update for Overnight Thunderstorm Potential... .MESOSCALE DISCUSSION... Issued at 959 PM CDT Tue May 12 2020 Quick update on the possible convective evolution overnight into Wednesday morning... Low-level water vapor imagery and 00z observed upper air soundings show two areas of moisture advection this evening. One is rooted around 700-600mb and is advecting in from western KS. The other is rooted closer to 850mb, and is advecting north out of OK. Meanwhile, there may be a subtle mid-level s/w over eastern CO. Observed soundings reveal some mid-level warming is ongoing at this time, which will likely limit where any elevated convection overnight can be rooted. RAP forecast soundings appear to be handling the incoming mid-level moisture from the west fairly well. Based on this, it still appears that there will be enough moistening above the inversion, combined with some lift from the CO s/w, to produce scattered thunderstorms after Midnight tonight. Unless the low-level moistening is being underdone by the models, storms should be rooted near/above 700mb, which may only allow 250-500 j/kg MUCAPE to be realized, with somewhat weaker shear. If the mid-level temps end up cooler, or if the low-level moistening is more pronounced, then up to 1000 j/kg MUCAPE could be realized, along with slightly better shear. Bottom line, confidence is increasing in elevated storms developing overnight into Wednesday morning, but the severe threat looks very conditional. If storms remain rooted at/above 700mb, severe weather would be unlikely. If storms can be rooted a bit lower, the potential would exist for hail up to quarter size. Martin && .SHORT TERM...(This evening through Friday night) Issued at 303 PM CDT Tue May 12 2020 Model sounding show periods of drizzle possible through the night with deep low-level saturation persisting. Current satellite total precipitable water analysis shows that deeper Gulf of Mexico moisture has been streaming northward across Texas reaching the confines of southern Oklahoma. This moisture will continue to spread northward tonight and interact with a north to south aligned elevated frontal boundary. This could spark off elevated showers/storms for late tonight into Wednesday morning across central and south central Kansas. Expected wind shear/instability aloft supports a few strong or possible marginal severe storms. This activity will slide eastward during the morning hours tomorrow. Meanwhile, models still suggest a warm front will migrate northward into the area with increasing low level moisture during the day tomorrow. A fairly strong cap aloft combined with residual low clouds could be a substantial prohibiter for surface based thunderstorm development in the wake of elevated morning convection. Therefore, believe next round of storms will be tied to convergence areas along the dry-line (positioned well west and southwest of central/south central KS) during the mid-late afternoon hours. Some of this activity could try and spread into south central Kansas later Wednesday evening, but it would be fighting against the capping temperatures aloft. Thinking that elevated storms should re- develop north of the warm front Wednesday night, however that moisture transport looks to target northeast Kansas thus sparing most of our area. Still cannot rule out a few storms from attempting to develop in the strong moisture transport axis over our area. A weak frontal boundary will sag southward during the day on Thursday and should be the focus for afternoon/evening storms. Shear aloft is on the weaker side but instability will be plenty high enough for severe multi-storms to materialize. The forecast becomes a little more uncertain for Thursday night into Friday. Although models do show a fairly pronounced mid-level front draped over the area with a long duration of warm moist advection aloft. This shows signs of generating numerous showers/storms across the region. Flooding could become a bigger issue across the area by Thursday night into Friday due to widespread recent rains of 1-2.25 inches soaking the ground soils and causing rises on local rivers. .LONG TERM...(Saturday through Tuesday) Issued at 303 PM CDT Tue May 12 2020 Thunderstorm chances will continue for Saturday across the region with chances tapering off by late Saturday night, as a more substantial frontal boundary pushes east of the region. High confidence of dry weather to prevail for Sunday-Tuesday as long range models show well pronounced upper ridging building over the central plains. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 642 PM CDT Tue May 12 2020 *Low CIGs and DZ/BR to linger into at least Wednesday morning *SHRA/TSRA possible overnight, and again later Wednesday Low CIGs continue to persist across much of Kansas this evening, and will likely linger well into Wednesday. It appears there will be enough low level lift for periods of DZ overnight into Wednesday morning. Additionally, SHRA and TSRA may develop after 05z, posing a risk of reduced VIS and possibly some hail. Confidence in TSRA development is lower for now, and I opted to remove any TSRA/VCTS mention in the TAFs. This will be closely monitored, though, with amendments if confidence increases. CIGs may rise some on Wednesday, with a few breaks in the clouds possible, especially southern Kansas. This factors in for where/if TSRA can redevelop Wednesday afternoon/evening. Stay tuned. EXTENDED OUTLOOK: TSRA will remain a concern through the upcoming weekend. Martin && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 49 72 64 82 / 30 30 20 30 Hutchinson 47 69 61 81 / 30 30 20 10 Newton 48 69 62 80 / 30 30 30 30 ElDorado 48 73 63 81 / 30 40 30 40 Winfield-KWLD 50 75 64 82 / 30 40 20 30 Russell 44 72 55 79 / 20 20 20 10 Great Bend 45 72 57 81 / 20 20 20 0 Salina 48 68 60 80 / 30 30 30 20 McPherson 47 67 60 80 / 30 30 30 20 Coffeyville 51 75 65 79 / 30 40 10 30 Chanute 49 74 65 78 / 20 50 20 50 Iola 48 73 64 78 / 20 50 30 60 Parsons-KPPF 50 75 65 79 / 30 40 20 40 && .ICT WATCHES/WARNINGS/ADVISORIES... None. && $$ MESOSCALE...RM SHORT TERM...CDJ LONG TERM...CDJ AVIATION...RM
Area Forecast Discussion
National Weather Service North Platte NE
628 PM CDT Tue May 12 2020 .SHORT TERM...(This evening through Wednesday night) Issued at 311 PM CDT Tue May 12 2020 A warm front accompanied by dry air is currently across Colorado this afternoon. The front will move east into wrn Nebraska tonight triggering scattered showers and isolated thunderstorms, mainly across nrn Nebraska. The dry air aloft should cause an area of fog to form affecting areas along and west of highway 83. Southeast winds and increasing moisture beneath the dry air would support an advection type fog. The RAP model shows this fog affecting the highlands with lower visibility than the valleys. The dry air and clearing should move through wrn Nebraska Wednesday morning and progress into ncntl Nebraska during the afternoon. A second area of showers and thunderstorms is expected to form off the Colorado Front Range and Laramie Range Wednesday afternoon. The showers and thunderstorms should move through wrn and ncntl Nebraska Wednesday night. The temperature forecast leans on the short term model blend which works well with warm air advection patterns, it incorporates deterministic model temperatures and tends to limit the fall in temperatures at night. Temperatures Wednesday will be moderated by the progress of the clearing line. Continued warm air advection, increasing cloudiness and a chance of showers and thunderstorms Wednesday night would suggest the short term model blend would be the preferred forecast tool vs the cooler guidance blend. .LONG TERM...(Thursday through Tuesday) Issued at 311 PM CDT Tue May 12 2020 Shower and thunderstorm chances continue Thursday, Friday and Saturday. This rain chance is associated with the slow eastward migration of an upper low off the coast of Oregon this afternoon. The upper low is expected to track through MT and SD placing wrn and ncntl Nebraska in the southern or warm advection side of the system. A weak area of Pacific high pressure will build into wrn and ncntl Nebraska ahead of the upper low and this should set up a stationary front for focus. Once this upper low moves into the Great Lakes late Saturday, a new upper low, currently across the Aleutians, should drop south and move into the Great Basin forming a long wave trof. The trof should flush warm air out the Desert Southwest and into the Central high Plains (CHP). WPC has outlooked the CHP for much above normal temperatures Monday and Tuesday. The GFS ensemble and other models keep the sfc low pressure near the WY-SD border and this would place the warmest air across wrn Nebraska and the Panhandle. Highs in the 80s are in place both days across all of wrn and ncntl Nebraska. Future forecasts could feature highs near 90 in some areas as suggested by the GFS guidance. H700mb temperatures will be rising to between 10C and 15C which supports highs of 90 or warmer if mixing heights can reach 700mb. The forecast is dry Sunday through Tuesday. The very warm air aloft predicted across the region should "cap" thunderstorm chances. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 627 PM CDT Tue May 12 2020 Ceilings will continue to fall overnight at both the KLBF and KVTN terminals, becoming IFR at the KLBF terminal and MVFR at the KVTN terminal overnight. Ceilings will become VFR late morning Wednesday with clearing skies expected into the afternoon hours. Fog will be possible across southwestern Nebraska overnight, impacting the KLBF terminal from 10z through 17z. Visibilities may fall off to 1SM overnight. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...CDC LONG TERM...CDC AVIATION...Buttler
National Weather Service Morristown TN
1003 PM EDT Tue May 12 2020 .UPDATE... EVENING UPDATE. && .DISCUSSION... As of this writing time, regional radar is showing light rain moving across middle TN and starting to reach the central plateau, however, surface observations indicate that this is not reaching the ground. There is alot of dry air remaining below 700 mb leading to this virga. As the surface high slowly shifts off of the FL coast tonight and lee cyclogenesis takes shape east of the Rockies, a warm front that currently stretches from AR across central MS and AL will slowly lift into the southern TN valley. Strengthening WAA and isentropic lift ahead of the front will continue to moisten the 700-500 mb layer late tonight, and soundings show some saturation nearing the surface after 09Z, so updated PoPs to reflect a gradual expansion of slight chance to chance from W to E between now and 09Z. The latest RAP and NAM, along with HREF ensembles suggest a strip of light showers in the 08-15Z timeframe from the central plateau through the central valley into NE TN and SW VA, so confidence is quite high that there will be at least scattered showers. QPF will be very light with generally 0.02 or less. The rest of the forecast remains on track. RG && .AVIATION... 00Z TAF DISCUSSION. VFR will generally prevail through the TAF period, but a warm front lifting into the southern Appalachians will begin increasing mid level moisture late tonight. As a result, cigs will lower through the night with a BKN to OVC layer between 3 and 5 thousand feet developing after 08Z at TYS and TRI, while higher cigs dominate at CHA. Isolated showers are also possible late tonight into late Wednesday morning, but coverage is low confidence, so included VCSH and Prob30 groups for a few hours at TYS and TRI which could result in very brief periods of MVFR cigs and vis. Conditions will rapidly improve by late afternoon. RG && .PREV DISCUSSION... /ISSUED 255 PM EDT Tue May 12 2020/ SHORT TERM (This Afternoon through Wednesday)... The period of below normal temperatures continues throughout the short-term forecast. Temperatures as of 2 PM are in the upper 50s to mid 60s for most locations. Seeing more cloud cover today compared to the last couple of days with increased moisture in the mid- levels. Mid to upper level flow is generally northwesterly with a closed upper level low to the north across New England. Seeing a few weak shortwave troughs in this northwesterly flow rotate through the area. At the surface, a warm front extends across north Texas to the east into the Lower Mississippi River Valley. The low-levels across the southern Appalachians remain dry with surface dewpoints currently in the 30s. PW values are higher than yesterday and range from around 0.5-0.6 inches across northeast Tennessee/southwest Virginia to near an inch for southwestern portions of the forecast area. These values near an inch are much closer to normal for mid- May. Current radar imagery indicates a few light returns showing up across northern Alabama associated with lift to the north of the warm front. There are some observations of the precipitation reaching the ground in northwest Alabama. Overall, expect the low-levels remain too dry for rain this afternoon and evening. The area of isentropic lift to the north of the front will continue to increase overnight. Look for best chances of any precipitation around 5 AM - 11 AM Wednesday morning when this area of lift moves through. Warm air advection will return to the area later this evening into the overnight hours as the low-level high shifts to the east. Overnight lows will be warmer than the last few nights in the low 40s to low 50s for most locations. Rain chances will decrease late tomorrow morning into the afternoon from south to north. Overall, any rainfall will be light with amounts under a tenth of an inch. Highs tomorrow will range from low 60s in northeast Tennessee and southwest Virgina where clouds and light precip. will linger longer to upper 60s to low 70s for locations generally south of I-40. MA LONG TERM (Wednesday night through Tuesday)... Some scattered showers may still linger Wednesday night as the front continues to move northward towards the Ohio River Valley. However, forecast models still indicate that the best lift will remain to our west closer to the shortwave. Ridge begins to build in strength quickly on Thursday and temperatures will also increase in response. Expect high temperatures to reach into the upper 70`s and even the 80`s. With the building ridge will come more southerly winds which should help keep dew point values somewhat elevated, and these combined with the strong daytime heating means we should see some isolated/scattered showers and thunderstorms through the end of the week and into the weekend. Best precipitation chances will be over the higher terrain that may help spark showers and thunderstorms, especially along the Cumberland Plateau into SW Virginia along the outer edge of the surface high. Towards the end of the weekend a cold front will move down from the Ohio Valley, but there is not much of a push with this front and the higher moisture associated with it remains further north closer to the low. So we will see an increase in precipitation chances, but coverage and QPF amounts are still expected to be somewhat limited. After the front moves through a ridge quickly builds in behind it and temperatures remaining near or above normal. ABM && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 53 76 58 81 62 / 20 20 0 10 0 Knoxville McGhee Tyson Airport, TN 51 70 54 81 61 / 30 30 0 10 0 Oak Ridge, TN 50 69 53 81 60 / 30 40 0 10 0 Tri Cities Airport, TN 43 63 51 78 56 / 30 30 10 20 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$
Area Forecast Discussion
National Weather Service San Francisco Bay Area
833 PM PDT Tue May 12 2020 .SYNOPSIS...Isolated to scattered rain showers will remain possible at times through early Thursday, with the best chance of precipitation over the North Bay. Temperatures across the interior are forecast to remain below normal through Thursday, while coastal temperatures will be near seasonal averages. Drier conditions and slightly warmer temperatures are expected from Thursday through at least midday Saturday before cooler, unsettled conditions return late in the upcoming weekend. && .DISCUSSION...As of 8:30 PM PDT Tuesday...Isolated shower activity has decreased since early evening and all shower activity is expected to end by sunset. Dry conditions are forecast overnight and through about midday Wednesday. The longwave upper trough responsible for our wet weather over the past few days remains nearly stationary offshore with its axis centered along 130W. Two more shortwaves moving through the longwave trough are expected to trigger additional shower activity, the first between late Wednesday morning and Wednesday afternoon, and the second from late Wednesday night through about midday Thursday. Precipitation in both cases is forecast to be light and primarily confined to the North Bay, although the 00Z NAM and latest HRRR indicate isolated light showers from San Francisco southward, especially on Wednesday afternoon and evening. Additional rainfall through Thursday is forecast to be a quarter inch or less in the North Bay, with no measurable rain or just a few hundredths elsewhere. Inland temperatures will remain below seasonal averages through Thursday, while coastal temps hold near normal. Dry conditions will return to all areas by Friday, as will warmer temperatures, as a shortwave ridge briefly develops over California. Dry conditions will then likely persist into Saturday morning before the next late-season system spreads rain across our area from Saturday afternoon through Sunday. Models agree that the system due in next weekend will be stronger, and track farther south, compared to the current system. Therefore, precipitation is likely to be more widespread, especially across the southern part of our area. Also, thunderstorms could develop by late Sunday night or Monday as a cold upper low tracks across northern California. && of 5:59 PM PDT Tuesday...for 00z TAFs. VFR. A few isolated showers will diminish by sunset. VFR to MVFR ceilings and a local patch or two of valley fog is possible late tonight and Wednesday morning. Light to moderate showers arrive over the North Bay Wednesday morning with MVFR to IFR developing, elsewhere mainly MVFR to VFR. Vicinity of KSFO...VFR to MVFR tonight, VFR Wednesday. West wind to 15 knots this evening diminishing to light and variable early Wednesday morning. West wind increasing to 10 to 15 knots in the afternoon and evening. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...VFR to MVFR tonight, VFR Wednesday. West to northwest winds diminishing and becoming light and variable tonight. West winds redeveloping Wednesday. && of 5:25 PM PDT Tuesday...Generally light to locally moderate south to soutwest winds will persist through tonight before winds over the southern waters begin to transition back out of the northwest. Southerly winds will briefly return across the southern waters tomorrow afternoon as another weak boundary moves through. West to northwest winds will then return later this week. Mixed seas will continue with a moderate northwest swell and a longer period southerly swell. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...None. $$ PUBLIC FORECAST: Dykema AVIATION: Canepa MARINE: AS Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Pocatello ID
135 PM MDT Tue May 12 2020 .SHORT TERM...tonight through Thursday night. A low pressure system off the Pacific Northwest coast continues to send waves of moisture through central and east Idaho. We are seeing showers and a few thunderstorms drift through the region. This activity will continue through the night, although the odds for thunder will decrease with nighttime cooling. A lake wind advisory is in effect for this evening for the American Falls Reservoir where winds of around 20mph were observed at Aberdeen and Sterling. We may see a few more showers on Wednesday and Thursday as the low pressure system slowly advances inland. The increase in clouds/rain will produce lower temperatures as well. Winds are expected to remain breezy on Wednesday but not so much on Thursday. Lake wind conditions may be realized again on Wednesday. 13 .LONG TERM...Fri through next Tue night. The upper level low responsible for all the showers and thunderstorms previous to this day actually starts lifting out from its nearly stationary positions on the OR-CA coast and moves through southern Idaho during the day Fri. This still means dry northwesterly flow develops Fri night and continues during the day Sat, for the driest day of the seven days in the complete forecast. Another closed low slides into the OR-CA coast, and starts up a repeat of stormy weather. However, it does not linger as long out in the Pacific. By Wed/Wed night, just outside of this forecast period, this upper level low is moving through Idaho. Both lows are creating enough unstable conditions that daytime heating should mean thunderstorm activity every afternoon and evening except Sat. At this time, there are no significant impulses bringing in a strong front, so do not expect thunderstorms to be severe. Messick && .AVIATION...Extensive cloud cover has been slow to leave, and most model guidance has eliminated TSRA in the Snake River plain and eastern Magic Valley. Satellite imagery paints a different story, with a large hole in the cloud cover moving eastward and into eastern Idaho at this time. So have kept TS activity to just VCTS for KIDA, KPIH, and KDIJ. KSUN and KBYI are in much more stable air on most products, so have lowered expectations at those two airdromes to VCSH. A second band of clouds, with scattered SHRA, is expected after 13/06Z in eastern Idaho. The SHRA surrounds KSUN in the mountains, so have left that and KBYI as VCSH. However, the HRRR indicates KPIH and KIDA to take a more direct hit, so have a period of -SHRA for both airports. For KDIJ, this second wave should actually bring marginal VFR along with the showers. Wind-wise, every location is looking for elevated west to southwest wind for much of the night, with only KSUN slowing and shifting to its normal northwest flow. KPIH and KBYI likely to stay at least southerly. Messick && .PIH WATCHES/WARNINGS/ADVISORIES... Lake Wind Advisory until 10 PM MDT this evening for IDZ054. && $$
Area Forecast Discussion
National Weather Service Phoenix AZ
444 PM MST Tue May 12 2020 .UPDATE...Updated Aviation Discussion. && .SYNOPSIS... A cooling trend will bring temperatures back to around normal readings beginning today, lasting through Friday while dry conditions prevail. Increased afternoon breeziness will be common for much of the week as several weather systems move well north of the area. The fire weather threat will remain elevated as well. Increasing high pressure into the weekend will lead to warmer temperatures and highs once again reaching near 100 degrees. && .DISCUSSION... Dry westerly flow across the region has now pretty much cleared skies entirely across our CWA this afternoon and dropped sfc dewpoints into the 20`s at many lower desert locations. These dry conditions (Rh`s in the high single-number to mid-teen range) and locally gusty winds are resulting in elevated fire danger levels as well. Winds have been strongest at the usually-favored locations across SW Imperial County, with gusts over 30 mph already being reported. Latest NAM-3km and HRRR high-res models continue to forecast the winds to continue to increase through the remainder of the afternoon/evening hours. with gusts to 50 mph possible. Thus, a Wind Advisory remains in effect through 5 am Wed for SW Imperial County. Highs today are still expected to top out in the low-mid 90`s, noticeably cooler than they have been the last few days. Further cooling is still forecast for Wednesday as 500mb heights lower a bit more, with lower desert highs falling into the upper-80 to low-90 range, along with some afternoon breeziness once again. These near to slightly below normal temperatures look to last through Thursday before weak ridging begins to move in from the west starting Friday. Another deep trough is shown dropping out of the northern Pacific on Friday before slowly moving southeastward into the Pacific Northwest this weekend. This trough will amplify the ridge already in place across the Southwestern U.S. leading to further warming across our region. Latest model trends have slightly higher heights and warmer temperatures building over our region which should push lower desert highs close to 100 degrees for this weekend. Into next week, much higher model spread is seen as the closed low potentially moves into California and the Great Basin next Monday into Tuesday. This should lead to a bit of a dip in temperatures for early next week and potentially even more if the trough continues to sag southward into our region sometime during the middle of next week. Even if the trough were to move through the Desert Southwest at some point next week, it is highly unlikely it would bring much in the way of any rain chances to the region. The main impact from next week`s trof will likely be an increase in winds and fire danger levels. && .AVIATION...Updated at 2345Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Gusty westerly winds will continue through this evening and for a few hours after sunset. The strongest gusts this afternoon may reach the 20-25 kt range although most will remain below 20 kts. The return of the overnight easterly winds are less certain, and may not develop until the 9-12Z timeframe. As such, there may be periods of light speeds, mostly AOB 8 kts, and variable directions beginning very late tonight and lasting through tomorrow morning until the westerly winds resume around 19-20Z. Southeast California/Southwest Arizona including KIPL and KBLH: Strong, westerly and southwesterly winds will remain in place through this evening and much of the night. At KIPL, wind gusts nearing 30 kts may be common until early tomorrow morning. Occasionally stronger "mountain rotor" winds may reach the terminal area. At KBLH, wind gusts of 22-26 kts are likely until 6Z. For tomorrow, gusts will return by the early afternoon but at speeds weaker than the last two days. && .FIRE WEATHER... Friday through Tuesday: Warmer temperatures are expected for the upcoming weekend, with lower desert highs likely returning to near 100 degrees by Sunday and Monday along with widespread dry conditions. Afternoon humidity levels will remain low in the teens across all districts while overnight recovery improve to a 30-40% range in eastern districts and closer to 50-60% in western districts. Stronger winds and cooler temperatures are forecast for Tuesday, as a late-season Pacific low pressure system approaches the region. Gust speeds 20-30 mph will be possible, even locally 35-40 mph across southeast California, enhancing the fire danger particularly in areas with abundant cured fine fuels. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...Wind Advisory until 5 AM PDT Wednesday for CAZ562. && $$ DISCUSSION...Percha/Kuhlman AVIATION...AD FIRE WEATHER...Percha/Benedict/MO
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Wednesday) Issued at 409 PM CDT Tue May 12 2020 Plenty of challenges remain with the forecast in the next couple of days. For today, radar has continued to show very light returns with drizzle occurring in east central KS this morning into the early afternoon due to weak isentropic lift. Forecast soundings (NAM/RAP/HRRR) in Emporia keep the low levels saturated through the evening and overnight hours, and areas further north toward Topeka and Manhattan show the low levels gradually becoming saturated late this evening and remaining so overnight. As such, have added drizzle to the forecast increasing north with time this evening and lasting through the overnight hours across much of the CWA. With WAA increasing, temperatures should remain steady or even rise slightly through the night with lows expected in the mid to upper 40s. By early tomorrow morning, WAA increases further with a strengthening LLJ of 30-40 kts. This is when we`ll be watching for the first round of storms, some of which could potentially become strong. The exact timing and placement of storms remains uncertain as some models have placed these more in north central KS while other runs have them in east central KS. Regardless, a brief window of stronger storms at least looks like a possibility with elevated instability increasing after 12Z. The NAM seems to keep the better CAPE in north central KS (up to 1000 J/kg), while the RAP carries this instability into east central KS during the mid to late morning as well. 0-6 km bulk shear of 25-35 kts keeps the strong storm potential more in question during this time frame, but with the LLJ and the instability, can`t entirely rule out some large hail with a few storms. The next chance for thunderstorms comes tomorrow evening, but this also comes with uncertainties. Low pressure deepens in eastern CO with most models showing storms initiating ahead of a dryline in western KS during the late afternoon/early evening. This also coincides with a weak mid-level shortwave moving over the state during the 18-00Z time frame, and the LLJ is expected to strengthen further to 40-50 kts late in the evening. Questions remain on when and if storms will get going with a strong cap in place, but these factors could result in enough lift to overcome that cap. The other question is how much instability -- the NAM has MUCAPE of up to 2500- 3000 J/kg in east central KS, while the GFS has considerably less based on forecast soundings. Based on the elevated nature of these storms, large hail and some damaging winds are the main hazards. .LONG TERM...(Wednesday night through Tuesday) Issued at 409 PM CDT Tue May 12 2020 By Thursday morning, a frontal boundary looks to extend from southwestern to north central KS, which moves across the state during the day and will be the focal point for the next chance of storms. The best chance looks to be in east central KS along and southeast of the boundary by the late afternoon. CAPE of 1500-2500 J/kg could once again bring the threat of hail and damaging wind, although it is worth mentioning that the NAM keeps this area more capped while the GFS erodes the cap during the afternoon. The frontal boundary remains in the area through Friday and Saturday with on and off chances of showers and storms during this period, although am not expecting more rounds of severe weather at this time. The main concern by this point is the potential for minor flooding and locally heavy rainfall, especially over areas that may see repeated rounds of storms. Sunday afternoon into Tuesday, a drying pattern is expected to return as an amplified ridge moves into the area. Temperatures are generally expected to reach the 70s and 80s for the afternoon, but could reach the mid 80s by Tuesday with the strengthening ridge. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 633 PM CDT Tue May 12 2020 Not much change from previous forecast. Flying conditions are expected to deteriorate through the overnight period with CIGS dropping to IFR and drizzle possible after 06Z. A further reduction to LIFR CIGS is looking more likely after 09Z at all terminals. Thunderstorm development still looks possible early tomorrow morning, so have continued mention of VCTS by 15Z. Some improvement is expected during the afternoon, but IFR CIGS should remain in place much of the period. Will monitor trends for the possibility of another round of storms developing late in the period. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Picha LONG TERM...Picha AVIATION...Teefey
Area Forecast Discussion
National Weather Service Tulsa OK
927 PM CDT Tue May 12 2020 .DISCUSSION... Warm front, currently located just south of the Red River this evening, will begin to lift north overnight. Areas of light rain/drizzle will likely persist north of boundary with a slight chance for an isolated thunderstorm or two as low level jet begins to develop. Whatever precipitation does occur should remain relatively light both tonight and into the day Wednesday with only minor QPF amounts. Storms that develop in southwest Oklahoma Wednesday afternoon may begin to weaken significantly as activity moves into eastern Oklahoma Wednesday evening/overnight as CIN increases/boundary layer begins to stabilize. Taking a quick look at latest NAM, HRRR and WRF-NSSL models continue to support this scenario. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...None. AR...None. && $$ SHORT TERM...12