Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/13/19

Area Forecast Discussion
National Weather Service Dodge City KS
1020 PM CDT Mon Aug 12 2019 ...UPDATE TO SYNOPSIS... .SYNOPSIS... Issued at 1020 PM CDT Mon Aug 12 2019 WV imagery indicates a westerly flow aloft prevailing across the Western High Plains. Near the surface, a near stationary frontal boundary extends from the Texas Panhandle eastward into western Oklahoma. && .SHORT TERM...(This evening through Tuesday) Issued at 312 PM CDT Mon Aug 12 2019 A weak surface front was located along the southern counties with Oklahoma this afternoon. A few thunderstorms will persist along this boundary through about 9 pm before moving father south into Oklahoma. By Tuesday evening, upslope southeasterly flow is expected to develop across the plains, with an area of surface convergence in extreme northeastern Colorado. Thunderstorms will develop in this convergence with surface heating and propagate southward and southeastward into western Kansas in the evening. The storms will be severe with large hail and damaging winds in the evening, especially before reaching as far south as I-70, then gradually decrease in severity during the late evening and overnight. It is uncertain how this storm cluster will track; but the most favored area for now is from Scott City southward to Garden City and Meade. High winds and heavy rain may be a concern into the early morning hours Wednesday in places like Garden City, Ulysses and Liberal. If the storm cluster is father east then Dodge City and Jetmore could receive heavy rain as well. .LONG TERM...(Tuesday night through Monday) Issued at 312 PM CDT Mon Aug 12 2019 Another cluster of thunderstorms is expected Wednesday evening in a similar setup. Much of western and central Kansas has a chance of thunderstorms Wednesday night. The same pattern will hold through Friday, with the best storm chances shifting north to around Interstate 70. But the aforementioned upper level ridge should suppress rainfall over the weekend to a more isolated basis. In general, temperatures will continue to be warmer along the Oklahoma state line and cooler near I-70. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 619 PM CDT Mon Aug 12 2019 Scattered thunderstorms will be possible over the next few hours near the Oklahoma border which will include the Liberal area. Wind gusts in excess of 35 knots is not completely out of the question with these storms. Bufr soundings indicate mainly lower VFR ceilings through 03z Tuesday at Liberal. VFR conditions can also be expected across western and north central Kansas early Tonight. Winds tonight outside the thunderstorms will be northerly at less than 10 knots. RAP and NAM soundings do suggest that there will be an increase in moisture in the 2000 to 3000 ft AGL level at Dodge City, Garden City and Hays after 09z Tuesday. This may produce some scattered ceilings around daybreak in the MVFR category. Any clouds that do develop late tonight will erode by 15z Tuesday. && .PRELIMINARY POINT TEMPS/POPS... DDC 66 91 64 89 / 10 0 30 10 GCK 62 91 62 90 / 10 0 60 20 EHA 63 91 63 90 / 20 0 60 20 LBL 65 91 63 90 / 40 0 50 20 HYS 66 90 63 86 / 10 0 30 20 P28 69 91 66 90 / 40 0 20 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JJohnson SHORT TERM...Finch LONG TERM...Finch AVIATION...Burgert
Area Forecast Discussion
National Weather Service Grand Forks ND
1004 PM CDT Mon Aug 12 2019 .UPDATE... Issued at 1004 PM CDT Mon Aug 12 2019 Stalled frontal zone near our western CWA still delineate more unstable air mass and trends continue to show thunderstorm activity weakening as it moves further east away from favorable region into more stable air mass. Still, we are we are seeing some redevelopment towards west central MN, lingering showers in the northern RRV, and closed low upstream progressing eastward with shower/storm cluster approaching our west. CAMS still indicate more widespread activity spreading northwest to southeast late tonight thorugh midday Tuesday before decreasing in coverage and ending west to east. Adjustments made to reflect current trends and towards CAMs consensus. UPDATE Issued at 642 PM CDT Mon Aug 12 2019 Better defined "lull" in measurable precip returns on radar across our south and west with redevelopment of showers across north north central valley, while more reorganized areas of showers transition east from our far eastern CWA. Adjustments made to reflect these trends and better time upstream redevelopment of showers. RAP analysis does show some instability along stalled frontal zone in our west, but this should show decreasing trends ,and with isolated activity may redevelop (or just some drizzle) overall there should be a "dry" period during evening/overnight before next upper low transitions in from the northwest. Thunderstorm can`t be ruled out in our far west and south, but trend will be for showers to be favored due to decreasing instability trends over our CWA. && .SHORT TERM...(This evening through Tuesday) Issued at 343 PM CDT Mon Aug 12 2019 Rainfall continues to be the main story in the short term. The rain has pretty much ended at Fargo and is almost done now at Grand Forks too. The steadiest rain has shifted into northwest Minnesota, but it will continue to decrease in coverage there this evening. This will bring somewhat of a break in the steady precipitation across the area. How much of a break is the main question. The 500mb low over northeast Montana and northwest ND will continue to push slowly eastward tonight. There has been some clearing across the western Dakotas, where some modest instability has developed. There is decent bulk shear, but not seeing much of a low level jet tonight. The best forcing will be right around the 500mb low. SPC did issue a mesoscale discussion a little bit ago talking about the potential for a few strong storms across northwest and north central ND late this afternoon into the early evening. High resolution model guidance also shows a few stronger storms developing out west and possibly holding together as they track into central ND later this evening. Will have to keep an eye on that possibility. Otherwise, extensive cloud cover remains across the entire FA, which limited the instability here. However, models show this cloud cover holding overnight and into Tuesday, which will hold temperatures up tonight and down Tuesday. Think pcpn chances will increase again on Tuesday as the 500mb short wave moves through, but the bigger story is that constant precipitation is not expected. There will be breaks at times tonight into Tuesday. .LONG TERM...(Tuesday night through Monday) Issued at 343 PM CDT Mon Aug 12 2019 The rain should finally begin to exit out of the FA Tuesday night. Cool and dry weather mid week will give way to more seasonal late- summer weather with highs in the 70s/low 80s and chances for showers and thunderstorms. Wednesday... Surface high pressure building in behind the Mon/Tues storm system will be accompanied by a cooler airmass that will keep temperatures in the upper 60s and low 70s for Wednesday. Light westerly winds under partly to mostly cloudy skies will allow for comfortable weather for mid-August. Thursday... Guidance continues to indicate northwesterly flow aloft will allow a weak upper level impulse and an attendant surface trough to move into the region Thursday/Thursday night. Since forcing for ascent will generally be weak only light and scattered showers are expected. The potential for thunderstorms will largely be dependent on the timing of the wave. A later arrival time will aid in low to moderate destabilization via prolonged daytime heating and low level moisture advection into the region. However, confidence in timing, and therefore thunderstorm chances, is low at this time due to high model spread. Friday through Sunday... Ensemble and deterministic guidance continue to suggest a return to a more typical summer time pattern by the late week/weekend period with more zonal flow aloft and temperatures/dewpoints back into the 80s and low 60s respectively. Chances for showers and thunderstorms will accompany this warmer weather as upper level impulses propagate through the region within the mean flow. Confidence is generally low on specific timing for rain/T-storm chances with high variation in both deterministic and ensemble member solutions noted within this period. Monday... Long range ensemble guidance suggests that the start of the next work week should be more quiet than the weekend with mostly dry weather and seasonal temperatures. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 642 PM CDT Mon Aug 12 2019 Showers continue to transition along and north of Highway 2 corridor with best coverage in north central MN. Stalled front to our west with high low level moisture had led to widespread stratus with ceilings varying from 500ft to 3500ft AGL, and overall trend for tonight twill be for IFR (if not LIFR) ceilings to prevail. Patchy fog can`t be ruled out, but most vis restrictions will be dependent on timing of current shower activity, or next round expected to move into northeast ND late tonight and shift southeast through the day Tuesday. VFR conditions may begin to return by the end of the TAF period as this second system moves east and drier air moves back into our region from the northwest. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...DJR SHORT TERM...Godon/Wasilewski/Long LONG TERM...Godon/AM AVIATION...DJR
Area Forecast Discussion
National Weather Service Hastings NE
614 PM CDT Mon Aug 12 2019 ...Aviation Update... .SHORT TERM...(This evening through Tuesday) Issued at 235 PM CDT Mon Aug 12 2019 Aloft: AMDAR/aircraft winds along with WV imgry and RAP dynamic tropopause analyses indicated moderately-amplified flow dominated by a subtropical high over the lwr MS river vly. The flow was less amplified and more zonal at 500 mb with the main belt of Westerlies acrs the Nrn USA. A small low and accompanying shrtwv trof was over SA-MT-WY. This trof will cross the Nrn Plns tonight and begin weakening tomorrow as it mvs into MN. heights begin to rise in its wake over the Rckys...the subtropical high will retrograde back into NM. This will result in W winds over NEB/KS becoming WNW. Surface: Wk low pres was over Srn SA. A wk cool front extended from this low down to a triple pt low near MCI and then SW to the OK panhandle. While the front mvs further E and S...the low over SA will sink into ND with cold frontogenesis to its W. Wk high pres will develop over NEB tomorrow while this front sags to the NEB/KS border by 00Z/Wed. Rest of this afternoon: Partly sunny. Extensive mid-lvl altocu are associated with a very wk shrtwv trof arcing from NM-KS...with diurnally-driven stratocu underneath. Temps will peak in the 80s 3-5 PM. Muggy. Tonight: Diurnal stratocu will dissipate early...and the mid-lvl clds associated with the very wk trof should move E of the CWA as that trof does. GFS/NAM/RAP/RDPS (Canadian) all bring in some mid- lvl RH from the SW after midnight. So skies should become mostly clr this eve and then turn partly cldy after midnight. Low-mid 60s...except in the Valleys from LXN-ODX where upr 50s are likely. Tue: The fcst reads mostly sunny...but may not have gone high enough with sky cover. Believe tomorrow will average partly cldy. Highs in the 80s. But Rooks county could reach 90F. Should be very comfortable with dwpts fcst to drop into the lwr 60s W of Hwy 81. That will be a nice albeit brief break from the humidity. .LONG TERM...(Tuesday night through Monday) Issued at 235 PM CDT Mon Aug 12 2019 Aloft: The last 2 runs of global mdls are tightly-clustered on low- amplitude WNW flow cont Wed-Thu. Spread begins to increase Fri and conts to increase thru the wknd. The last 3 EC runs and its ensemble mean place more emphasis on a low (currently offshore of BC) dropping into or just offshore of the Pac NW. This induces a transition to SW flow over NEB/KS. All other global mdls place more emphasis on a potent trof crossing the Can Prairies...which maintains WNW flow over the rgn. Interestingly...just looking at the 12Z mdl runs...the EC has come into the camp maintaining WNW flow as it keeps the BC low further W than its 2 prvs runs. So there may be a consensus forming toward WNW flow. Once the Can Prairies trof moves into Ontario Sat night...a broad ridge is fcst to form over the Plns. Surface: The cool front along the NEB/KS border should slip thru Tue night quickly followed by Nrn Plns high pres Wed. This high will slide to the E Thu with return flow developing. A Canadian cool front will drop into the Nrn Plns and cross the CWA Thu night or Fri mrng. Because of the uncertainty`s uncertain what will happen with this front. Will it stall acrs Nrn KS or head into OK? Either should dissipate. The EC tells a diff story. Another Canadian cool front is fcst to sag thru the Nrn Plns Sat...but it might not make it here if low pres forms over SW Canada. Lots of uncertainty heading into this wknd. Temps: Wed will be the coolest day of the wk. Much of S-cntrl NEB will only reach the 70s. Still a little below normal Thu...then near normal Fri-Mon. Precip: As is usual for summer...confidence is not high. Isold- sct tstms will form each day over the high plns (out to the W). As is typical...the GFS/NAM look overly aggressive...but there probably will be a small number of isolated storms that make it in here during the evening/nighttime hrs. There`s always a chance enough storms could form to grow upscale into an MCS that slides into the CWA. Just not enough confidence to say much more. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Tuesday) Issued at 610 PM CDT Mon Aug 12 2019 VFR conditions with light winds are expected through this TAF period. Midlevel clouds will diminish this evening, leaving mostly clear skies through most of the overnight. Then scattered and high clouds are expected to move back in Tuesday morning. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Kelley LONG TERM...Kelley AVIATION...Mangels
Area Forecast Discussion
National Weather Service Goodland KS
445 PM MDT Mon Aug 12 2019 .SHORT TERM...(This evening through Tuesday) Issued at 158 PM MDT Mon Aug 12 2019 Seeing subtle height rises today in mainly zonal flow aloft in the wake of last nights shortwave trough. The ridge to the west will amplify on Tuesday putting the central High Plains under more of a northwest flow. Appears to be a weak impulse coming out of Wyoming Tuesday afternoon and evening. At the surface, cold front has just about cleared the forecast area this afternoon with northwest winds behind it. Surface dew points have dropped slightly, but still remain mostly in the 60s, with the exception of far western areas where they drop off rapidly into the 40s and 50s. For tonight, expecting quiet weather. Did include a mention of patchy fog in south/western parts of the area where HRRR and RAP show reduced visibilities towards 12z, possibly moisture pooling along leading edge of return flow/frontal boundary stalled to the west. On Tuesday, expecting scattered thunderstorms to develop in northeast Colorado 19-21z as shortwave moves out of Wyoming and near cyclonic surface convergence associated with mesolow which develops in northeast Colorado. CAM ensemble mean shows a surface based instability axis of up to 2000 j/kg extending from northeast Colorado south/southeast along the Kansas-Colorado border area. Surface to 500 mb shear is forecast to be around 30-40 kts. Due to weak forcing, storm coverage will be somewhat limited, but those parameters suggest a few severe storms will be possible as storms track down the instability axis, with large hail and wind the primary hazards. Global models show QPF bullseyes Tuesday evening up to 2 inches, so cant discount locally heavy rainfall either. Temperatures through the short term period will be near to slightly below normal, with lows in the 60s and highs on Tuesday in the mid to upper 80s. .LONG TERM...(Wednesday through Monday) Issued at 249 PM MDT Mon Aug 12 2019 Synopsis... Showers and thunderstorms may be possible Wednesday through Friday, mainly in the afternoon and evening hours. Some isolated severe weather may be possible. Drier conditions are expected this weekend, but showers and thunderstorms may return to the Central High Plains early next week. High temperatures will increase from the mid to upper 80s Wednesday to the low 90s Thursday through Monday. Low temperatures will similarly increase from the mid 50s and low 60s Wednesday morning to the low to upper 60s this weekend. Discussion... Biggest change from previous forecast for the long term forecast period is that shower and thunderstorm chances have been increased for Thursday and Friday in the afternoon and evening hours. The increased chances for precipitation are generally for the eastern portion of the forecast area east of US Hwy 83. Not expecting widespread severe weather on either Thursday or Friday. The reason for the change is that newer model guidance is showing that the upper-level ridge over the southern United States is taking longer to strengthen and lead to reduced precipitation chances for the Tri-State area. At this point, some moderately strong northwesterly upper-level flow will be possible over the forecast area Thursday and Friday which could lead to some isolated showers and thunderstorms. There is a threat of severe weather Wednesday afternoon and evening. Lingering convection from overnight Tuesday may disrupt the thermodynamic support for thunderstorm formation later in the day on Wednesday, but forecast models are still indicating the possibility of 1500 to 2500 J/kg of CAPE as well as 40 to 50 kts of deep layer wind shear over much of the Tri-State area during that time frame. With a surface low developing on the lee side of the Rocky Mountains in eastern Colorado, there may be some enhanced surface convergence which would provide the initial lifting mechanism for storms. Right now, current thinking is the main threats are large hail and damaging winds, especially with any discrete convection which may form. While later this week may be drier, chances for showers and thunderstorms will likely return Sunday night and Monday afternoon and evening as an upper-level trough develops over the western United States. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 445 PM MDT Mon Aug 12 2019 KGLD, vfr conditions expected through the period. Winds at taf issuance from the northeast under 10kts decreasing to 5kts or less while veering to the east then northeast overnight. After 14z winds become southeast under 10kts rising toward 12kts by late afternoon. Fog/br possible in the 11z-13z timeframe and for now have visibility down to 5sm but could be lower. After 23z thunderstorms are anticipated near the terminal and could produce strong winds and locally heavy rainfall producing sub vfr cigs/vis. For now have VCTS to start things off. KMCK, vfr conditions through the period. A north wind under 10kts at taf issuance will become light and variable overnight then establish an east or east-southeast direction under 10kts after 18z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...024 LONG TERM...PATTON AVIATION...99
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1023 PM EDT Mon Aug 12 2019 .SYNOPSIS... Rainfall chances will slowly increase during the first half of the week, peaking on Wednesday with a weak cold front and remaining higher than normal into the weekend. Hot and humid conditions will persist through mid week, with a cooling trend toward the end of the week. && .NEAR TERM /THROUGH TUESDAY/... As of 1020 PM EDT: A few convection-allowing models, most notably the recent HRRR runs, have isolated showers regenerating just east of the southern Appalachians through the early morning hours. However, this appears overdone given the ongoing stabilization and general lack of overnight forcing. Thus, the rest of the night should remain quiet with regard to precipitation, with mainly mountain valley fog and low stratus making another appearance. Otherwise, the upper ridge over the Southern Plains will continue to build over the southeast thru the near-term, as troughing continues to push off over the Atlantic. An upper shortwave crossing the Upper Midwest tonight will move a sfc low toward the Great Lakes, with the associated front working its way toward the OH Valley by the end of the period. PoPs will ramp up most strongly near the end of the period Tuesday afternoon. The combination of expected mid 90s temperatures and low 70s dew points Tuesday afternoon has required posting a Heat Advisory from Franklin County, GA southward. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... As of 145 PM EDT Monday: A slight increase in mean mid-lvl flow and falling heights is expected Tuesday night. Within this regime, organized gusty tstms should develop upstream of the cwfa. Deep convection and/or it`s remnants may sag into the mountain Tuesday evening. Otherwise, warm and muggy conditions will linger. The bubble of the very warm and humid airmass will be displaced eastward a tad on Wednesday, but middle 90s are still probable along and SE of I-85 with another afternoon of heat index values in the lower 100s. The atmosphere as a whole remains moist on Wednesday and the upper pattern broadly cyclonically curved. Based on this, ensemble and blended model solutions blossom deep convective coverage to numerous in the afternoon. PWAT plan view progs show a continental airmass attempting to impinge upon the region but really makes only a limited penetration into the NC mtns on Thursday. Therefore, would not expect much deviation from climo pop as we return to maximum temperatures closer to normal. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 2 PM EDT Monday: Starting Thursday evening with the 500mb pattern showing a broad trough over the East with axis from the Great Lakes to FLorida and a elongated ridge over the SW. The surface front by Friday will be becoming stationary from the NE Gulf to the Carolina coast into early next week. Models continue to depict some sort of low development along the front over the Gulf. The GFS is a bit back and forth as to low development. The EC has a low to form on Friday and lingers this low wobbling around the FL Panhandle through the first half of next week. Perhaps there will be better agreement later in the week as to what happens with this low and how it will affect our weather. Keeping POPs at slight to low chance with the current uncertainty. The GFS has a strong northern stream shortwave crossing the Great Lakes on Sunday and bringing a weak cold front to our region by late Monday. The EC delays the arrival of the shortwave until at least Tuesday. May raise POPs a bit for northern zones late Monday. Temperatures will be near or slightly below normal. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... At KCLT and elsewhere: Showers and thunderstorms have dissipated quickly this evening and conditions should remain dry overnight. Confidence is fairly high in mountain river valley low stratus and fog making an appearance since higher stratus is not really indicated in profiles. Any low stratus east of the mountains is much less certain, but with MOS hinting at some lower end MVFR stratus in the Piedmont near KCLT. Will feature FEW010 there. Any thunder chances ramp up slowly on Tuesday as a front gradually approaches from the northwest. Will feature late day PROB30 for now, with the earliest onset in the mountains around KAVL. Expect light and variable winds to pick up from the southwest at less than 10 kt east of the mountains, except NW at KAVL. Outlook: Coverage of showers and thunderstorms will increase Tuesday night into Wednesday as a cold front and associated moisture/forcing arrive from the northwest. The boundary will stall southeast of the area mid to late week, with lower end convective chances persisting. Early fog/stratus will be possible each day across mountain valleys. Confidence Table... 02-08Z 08-14Z 14-20Z 20-00Z KCLT High 100% High 100% High 80% High 100% KGSP High 100% High 100% High 100% High 100% KAVL Low 55% Low 58% High 80% High 100% KHKY High 100% High 95% High 100% High 100% KGMU High 100% High 100% High 100% High 100% KAND High 100% High 100% High 100% High 100% The percentage reflects the number of guidance members agreeing with the scheduled TAF issuance flight rule category. Complete hourly experimental aviation forecast consistency tables and ensemble forecasts are available at the following link: && .GSP WATCHES/WARNINGS/ADVISORIES... GA...Heat Advisory from noon to 8 PM EDT Tuesday for GAZ026-028-029. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...HG/JPT SHORT TERM...CSH LONG TERM...DEO AVIATION...HG
National Weather Service Jackson KY
1106 PM EDT Mon Aug 12 2019 .UPDATE... Issued at 1106 PM EDT MON AUG 12 2019 Clouds have redeveloped across the area this evening. Temperatures currently range from the low to mid 70s across most locations. Very deep convection has initiated across IL, close to the warm front aligned from west to east. The latest model guidance continues to suggest convection conglomerating more into an MCS and moving into the I-64 corridor towards dawn. The latest mesoanalysis page shows the better instability gradient stalling a bit in the previous few hours. Still, a modest low level jet should develop overnight, helping to advect in at least some additional moisture/instability across eastern Kentucky. Given the model agreement, have increased PoPs to likely along and north of the I-64 corridor towards dawn. This complex should weaken as it moves southeast into the morning hours, and have attempted to reflect this in the grids, before additional convection refires in the afternoon. The rest of the forecast remains on track. Updates have been sent. UPDATE Issued at 810 PM EDT MON AUG 12 2019 Higher clouds are diminishing across the Commonwealth through early this evening. Given the trend, will allow for more of a mostly clear first half of the night. Clouds will then increase out of the northwest for the second half of the night, as convection develops across the Ohio Valley and looks to threaten our area closer to dawn. Based on the latest higher resolution model guidance and trends in observations, did slow the higher PoPs down a bit for now. Will re-evaluate PoPs later this evening. The rest of the forecast is on target. Updates have been sent. && .SHORT TERM...(This evening through Tuesday night) Issued at 505 PM EDT MON AUG 12 2019 Late today an upper level ridge was over TX and the lower Mississippi Valley, and largely zonal flow was over the northern part of the CONUS. Within the flow there was a shortwave trough embedded over the Midwest, with an associated surface low over IA. Very hot and humid air was present under the ridge, with temperatures in the 90s and dew points of 75-80 upstream from us over AR and West TN. The shortwave and surface low will move east during the short term period, passing to our north on Tuesday. Our low level flow will increase tonight and Tuesday ahead of the system`s cold front advancing toward us. This will advect hot and humid air into the region. Although increasing clouds will probably hold temperatures to near 90 (or possibly cooler) on Tuesday, our dew points will likely climb to the mid 70s. A broad upper trough will also be developing southward over the Ohio Valley and Mid Atlantic region on Tuesday, bringing lower geopotential heights and cooling in the mid/upper levels. This combo will result in very unstable conditions, with CAPE likely to reach 3-4K J/Kg. With a modest amount of shear expected as well, severe thunderstorms will be a threat. Because of the very warm atmosphere, wind is the primary concern. However, the large amount of instability could also present a hail threat from the most intense updrafts. This is all assuming convective development occurs with peak heating. While soundings seem to support it, the NAM and HRRR are looking very stingy, holding off main development on Tuesday to an area along the cold front as it is getting ready to exit our area to the south at the end of the day. To varying extents, models also show nocturnal development progressing east southeast across our area late tonight into Tuesday morning in association with the shortwave and low level advection/isentropic lift. This could obviously play a factor in the evolution on Tuesday. All this said, it`s not a high confidence forecast, and is a matter of presenting probabilities. Whatever occurs, activity is expected to be on the decline from northwest to southeast on Tuesday night, with most of it coming to at least a temporary end by morning. .LONG TERM...(Wednesday through Monday) Issued at 401 PM EDT MON AUG 12 2019 There is good model agreement with the overall upper air pattern forecast for the beginning of the forecast period, as troughing continues to dominate the eastern U.S. with upper ridging centered over the southwest U.S. This mean pattern will transition early next week as the upper ridging over the southwest U.S. expands eastward and the westerlies retreat north. There is some disagreement on how quickly this occurs, with the GFS tending to be slower in the evolution of the pattern and with the rising heights forecast for our area this weekend. While timing differences exist, the overall trend will be for warming temperatures as we move into the start of next week. At the surface a cold front will be southeast of the area by Wednesday morning. A few lingering showers could still occur on Wednesday before surface high pressure builds into the area for the end of the week. Dry weather will then prevail into early next week, though there will be a small chance for a few terrain induced thunderstorms near the VA border Sunday afternoon. Temperatures will be cooler in the wake of the cold front, but as surface high pressure shifts east over the weekend temperatures will once again be on the upswing. The 12Z GFS, which may be holding onto the eastern U.S. troughing a little too long pushes another cold front through the area late in the weekend or early next week. A more likely scenario, which is supported by the ECMWF, is that the front will stall in the OH Valley, not making it through eastern KY, and then pull back north. In either case the front should make it close enough to our area to bring a small chance of showers and thunderstorms for Monday. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 810 PM EDT MON AUG 12 2019 VFR conditions will prevail through 06z. Clouds will then be on the increase from the northwest between 06 and 12z, with the potential of showers and thunderstorms threatening between 08 and 12z. KSYM would stand the best chance of seeing localized impacts, but there is still some uncertainty regarding the intensity of the convection as it moves in late, so will only include VCTS for now. This convection will likely weaken as it moves southeast across the area; however, additional convection, some of which could be robust, will redevelop in the afternoon as a cold front approaches the area after 16z. There still remains some timing uncertainty with this, so will only mention a several hour window of VCTS at all TAF sites at this point. Light winds overnight will turn southwesterly at around 10 kts during the day on Tuesday, with gusts of 15 to 20 kts at times during the afternoon hours. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEOGERIAN SHORT TERM...HAL LONG TERM...SBH AVIATION...GEOGERIAN
Area Forecast Discussion
National Weather Service North Platte NE
621 PM CDT Mon Aug 12 2019 .SHORT TERM...(This evening through Tuesday night) Issued at 254 PM CDT Mon Aug 12 2019 Mainly dry conditions seen through the day will continue into the night across most of the CWA. A shortwave trough is tracking along the US/Canadian border just north of North Dakota this afternoon. A weak disturbance associated with the trough will travel into eastern South Dakota and northeastern Nebraska late this afternoon. The models are in some disagreement with precipitation in our CWA, however, the HRRR model continues to show very isolated showers and thunderstorms across north central Nebraska. Bounced back and forth with the thunderstorm chances across our north central counties late this afternoon and evening, but since a stray shower and thunderstorm cannot be completely ruled out, kept small PoP chances across this area for this afternoon. Elsewhere, conditions will remain dry through the remainder of the afternoon and into the overnight hours. Seasonable temperatures are expected overnight with lows in the 50s across western Nebraska and in the low 60s across central Nebraska. On Tuesday, temperatures will be slightly below seasonable normals with highs in the lower 80s across the region. A surface boundary across northeastern Colorado and southeastern Wyoming will interact with a disturbance by Tuesday afternoon which will increase precipitation chances across western Nebraska. Through the evening and overnight hours, any storms that do develop will track towards the east across the CWA. The greatest chance for strong thunderstorms at this time appears to be confined to portions of southwestern Nebraska. .LONG TERM...(Wednesday through Monday) Issued at 254 PM CDT Mon Aug 12 2019 Precipitation...The aforementioned surface boundary will remain anchored to the west of the CWA on Wednesday before shifting east later in the week. This boundary will continue to bring thunderstorm chances to the area through the end of the week as it shifts east and transitions out of the area. The best chances for widespread precipitation will be on Wednesday and Thursday from west to east. By Friday, precipitation chances begin to decrease, with the exception of some light PoPs across portions of northern Nebraska Friday evening, as high pressure begins to build back into the southern plains. Temperatures...Wednesday will be the coolest day of the week with high temperatures generally in the 70s across the area, which is around 5 to 10 degrees below seasonable normals. Temperatures will begin to increase from the southwest starting on Thursday. By the weekend, temperatures will return to the upper 80s to lower 90s in response to the aforementioned high pressure building over the southern plains. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 620 PM CDT Mon Aug 12 2019 Skies becoming clear this evening, followed by increasing clouds later tonight into Tuesday. Indications a few showers possible Tuesday morning across the western Sandhills, which could affect the KLBF terminal after 19Z. Introduced a tempo for -TSRA 20Z- 24Z. At KVTN, some increase in clouds Tuesday with VFR conditions expected. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Thorne LONG TERM...Thorne AVIATION...Roberg
Area Forecast Discussion
National Weather Service Marquette MI
730 PM EDT Mon Aug 12 2019 .SHORT TERM...(This evening through Tuesday) Issued at 354 PM EDT MON AUG 12 2019 Water vapor loop and RAP analysis shows a quasi-zonal flow across the Upper Great Lakes and models indicate this will remain over the next 24 hours. A weak shortwave noted moving through MN and western/southern WI was supporting light to moderate showers across much of MN into nw and southern WI this afternoon. General confluent flow aloft and sfc ridging into the area from high over Saskatchewan has kept conditions dry across the U.P. thus far today, although there is plenty of cu around with inland sfc dewpoints well into the 50s and 0-3 km lapse rates around 7C. Temps this afternoon despite clouds and the development of lake breezes have reached well into the 70s, except for 60s readings near the Lake Superior shore. Model soundings indicate there could be some weak instability along the WI border to support an isolated shra into early evening, but otherwise dry conditions are expected with cu likely dissipating after sunset but some high clouds could remain through the night. More prominent shortwave trough over the western Dakotas will slowly be approaching the region late tonight into Tue, so there could be an increase in weak forcing late tonight into Tue for some isolated shower activity, but again model trends suggest best chance for an isolated shower would be along the WI border as better forcing with shortwave stays south of area. Plenty of daytime cu is expected again on Tue. Expect min temps tonight generally falling into the lower 50s with even a few upper 40s readings at typical inland cold spots. Readings near the Great Lakes will be in the mid to upper 50s. Highs Tue will again be in the 70s with cooler 60s readings near Lake Superior shore in prevailing ne flow across area ahead of building sfc high pressure from nw. .LONG TERM...(Tuesday night through Monday) Issued at 327 PM EDT MON AUG 12 2019 Quiet weather looks to prevail through Thursday, with a gradual warm up expected through the end of the week and throughout the weekend. With the warm up, increasing humidity levels and chance for precipitation will return. As high pressure remains in control over the Upper Peninsula through Thursday, the weather is expected to remain fairly quiet. Tuesday night into early Wednesday there could be an isolated shower or two that works into southern parts of Upper Michigan as an inverted- trough digs south across Minnesota and Wisconsin. Otherwise, Wednesday and Thursday are shaping up to be beautiful days! Friday, high pressure shifts off to our southeast and a trough upstream of the region starts to drop towards the Upper Great Lakes. This will allow the pressure gradient to strengthen across the area with winds becoming southwesterly. This south-southwest flow will begin to bump in additional moisture back into the region, bringing back chances for showers and thunderstorms. Over the upcoming weekend, the upper-level pattern becomes increasingly amplified as a lead shortwave lifts northeast across the Upper Great Lakes, followed by the main shortwave tracking eastward across across the region later on. Therefore, we likely will be looking at multiple rounds of showers/storms Friday night through early Sunday morning. Models are still a bit inconsistent with the timing/placement, so overall confidence is low in regards to where and when the best chances for precipitation will be over the weekend. Given the warm, moist advection pattern, coupled with mid/upper level lift, this will support a period of active weather. MUCAPEs do not get terribly impressive over the weekend, but depending on the magnitude of the moisture transport and PWATs there certainly may be heavy rain that accompanies any thunderstorm activity. During the latter half of the weekend into early next week, the secondary, stronger shortwave will push east of the region putting us briefly under a stint of cold air advection and drier conditions. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 730 PM EDT MON AUG 12 2019 VFR conditions are likely to prevail thru this fcst period at KIWD/KCMX/KSAW. -SHRA may occasionally occur at KIWD thru Tue morning, but probably not much more than sprinkles this evening. Not out of the question that a -shra or sprinkles could occur at KCMX this evening. Winds will be under 10kt thru the period. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 354 PM EDT MON AUG 12 2019 Winds over the lake are expecteds to stay at or below 20 knots for the entire forecast period. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Voss LONG TERM...Ritzman AVIATION...Rolfson MARINE...Voss
Area Forecast Discussion
National Weather Service Pueblo CO
803 PM MDT Mon Aug 12 2019 .UPDATE... Issued at 800 PM MDT Mon Aug 12 2019 HRRR indicating some convection may fire in the next hour or so from the greater Canon City area ESE down towards Colorado City. Likewise have bumped up POPs this area for this evening. HRRR also showing it could be a rather busy day tomorrow on the far eastern plains as a few supercells moving south-Southeast are being indicated in the 00 UTC run. /Hodanish && .SHORT TERM...(This evening through Tuesday) Issued at 245 PM MDT Mon Aug 12 2019 Drier air has moved into the area today and only a few showers and thunderstorms have developed over and near the higher terrain. The I-25 corridor and westward will continue ot be the most favored area for thunderstorms development through this evening. However, there is still the possibility of a few storms developing/moving across the southeast corner of the state. Most, if not all storms end by about midnight. Tue the upper ridge will be centered over NM, and moisture will again be limited over southern CO. However, there will still be enough moisture and instability for some showers and thunderstorms to develop over and near the mtns. Tue afternoon, a disturbance moving out of WY and across northeast CO, could bring some thunderstorms into Kiowa county, but the forecast models are currently keeping the storm activity north of Kiowa county until after 00Z. Temps on Tue should reach highs in the upper 80s and lower 90s over the plains, with upper 80s and lower 80s in the high valleys. .LONG TERM...(Tuesday night through Monday) Issued at 245 PM MDT Mon Aug 12 2019 A flat ridge remains centered over Texas/Arizona/New Mexico/northern Mexico through much of the extended forecast period, leaving generally weak and undisturbed westerly to west-northwesterly flow over Colorado. TPW over the high terrain will run 50%-75% of normal, limiting convective potential somewhat, especially when compared to this past weekend and last week. Still, given strong afternoon heating, expect isolated to scattered storms to develop each afternoon over the mountains, with very isolated activity spreading to the valleys and I-25 corridor along outflow boundaries. The main threat with storms each day will be cloud to ground lightning, with flash flooding a slight possibility should one of the few slow-moving storms move over a burn scar. Gusty winds and small hail could be possible with a couple of storms, but weak shear and marginal instability will limit the threat. Now for some specific deviations from that discussed above. Tuesday night, a shortwave pushing east across the northern plains will have sent a cold front down the central plains. Models continually produce a south-moving MCS along the CO/KS border, fueled by moist southerly flow. Given this system will move through overnight, the main threats will be gusty winds, heavy rainfall, and cloud to ground lightning. It appears as though the main areas impacted will be Kiowa, Prowers, Bent, and Baca Counties. A similar setup is plausible Wednesday night, with the MCS likely slightly further east, just clipping the CO/KS border. On Friday and Saturday, the ridge flattens further as a series of shortwaves move across the northern Rockies, potentially enhancing shower and thunderstorm development over the plains those afternoons and early evenings, depending on the southward extend of the waves and outflow activity from northern storms. Models build the ridge back over Colorado Sunday and Monday, limiting the majority of precipitation to the mountains once again. Afternoon temperatures during the extended period will remain above normal, with highs spanning the 90s across the plains, near 90 in Colorado Springs, and 80s across much of the high valleys. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 245 PM MDT Mon Aug 12 2019 KCOS, KALS, KPUB could see showers/tstms in the vicinity this evening, and then again during the afternoon and evening on Tue. The main storm threats will be lightning, gusty outflow winds and brief locally heavy rain. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HODANISH SHORT TERM...28 LONG TERM...LINE AVIATION...28