Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/24/18

Area Forecast Discussion
National Weather Service Gaylord MI
949 PM EDT Sat Jun 23 2018 .UPDATE... Issued at 947 PM EDT Sat Jun 23 2018 Overall pattern across the upper Great Lakes is pretty weak this evening...weak low pressure (1005mb) lies over Lake Erie...with a cold front to the north of the state just clipping far northern Lake Superior. Well-defined short wave trough/PV anomaly over eastern Iowa/northern Missouri evident in water vapor imagery...and showers have been developing ahead of this feature along the Mississippi River and tracking east-northeast. Had an "explosion" of light rain across the tip of the mitt and Straits region starting late already had to make one forecast adjustment to cover that. Think forcing that is driving this precipitation will wane this evening and this area of precipitation should thin over northern Lower (but expand over northern Lake Michigan). Meanwhile...Iowa short wave trough is expected to move across southern Lower Michigan overnight...with an increase in shower activity ahead of it as it interacts with deep moisture across Lower Michigan (precipitable water values over 1.50 inches) and some weak instability. Precipitation development likely to focus around deformation axis to the north of this short wave trough...with some potential for heavier downpours mainly along/south of the M-55 corridor. Flash Flood Guidance mostly over 3.00"/3hr across this area so it`s unlikely this will be impactful. Fog also expected to be an issue tonight over northeast Lower and the higher terrain across the interior...could be dense in spots especially near Lake Huron. && .NEAR TERM...(Through Tonight) Issued at 349 PM EDT Sat Jun 23 2018 ...Significant rainfall possible late tonight for central Lower... High Impact Weather Potential...Potential for locally heavy rainfall along and south of M-55 late tonight into Sunday morning. Pattern Synopsis/Forecast...Weakening vertically-stacked low over the eastern Great Lakes is shearing out this afternoon with a weak upper ridge sliding over northern Michigan in its wake. Abundant low level moisture (PWs in excess of 1.5") over much of northern Lower led to widespread stratus and areas of fog today, as well as scattered morning showers. Those showers have mostly fizzled out with the departure of the better forcing. Daytime heating across northern Lower has been limited by the formidable cloud cover in most areas, leaving temperatures generally stuck in the 60s (except for Frankfort and Manistee...the only areas where temps have pushed into the low 70s). Meanwhile, fewer clouds over eastern Upper allowed temperatures to climb into the mid to upper 70s there. Late this afternoon there is a possibility for some additional isolated showers popping up south of Grand Traverse Bay. Weak low level convergence is already starting to take shape in that area, and this may be enough to trigger some convection, which most hi-res guidance begins to develop around 5pm. Given weak forcing, virtually non- existent instability, and light wind fields from the surface to the mid levels per APX VAD wind profile and forecast soundings, this activity should remain weak and diminish with loss of daytime heating this evening. Had tossed in a slight chance of thunder earlier today for this area when it looked like it might see more sun, but since that hasn`t happened decided to remove it. Later tonight, a digging longwave trough over eastern Canada will carve out a potent shortwave over northwest WI and northern Lower MI. This stronger forcing looks much more promising for producing more significant rainfall south of M-72 where the corridor of higher PWs (in excess of 1.5") will reside, and especially along/south of M- 55. Models have been hinting at this since at least yesterday, but today there is good agreement, and 12Z hi-res guidance strongly supports the idea. Time of arrival will be well after midnight, perhaps closer to daybreak Sunday for some areas. The concern is that this activity will be slow-moving given the anemic synoptic wind profile, and combined with significant forcing and abundant moisture...will this lead to prolonged heavy downpours for some areas? Latest HRRR reflectivity paints this picture and frankly looks a bit concerning. HREF ensemble mean precip shows localized rainfall in excess of 1 inch along/south of M-55 by 8 AM Sunday, but individual members do show potential for locally 2+ inches in spots. Areas most at risk for this very heavy rainfall would be roughly from around Manistee to Gladwin, with lighter amounts across the rest of northern Lower and likely very little across eastern Upper. The good news is that given how dry we`ve been lately (25 to 75% of normal for month-to-date rainfall), think the ground shouldn`t have too much issue handling these amounts...unless significant rainfall occurs over a very short period of time. Latest 3 and 6 hour flash flood guidance would require around 2 to 4" of rainfall to lead to issues along/south of M-55, so not anticipating too much cause for concern. But we`ll be monitoring this potential closely as new model data comes in through the evening. Instability will be limited, but forecast soundings show classic near-saturated column with tall, skinny CAPE. Not anticipating storms given very low instability, but wouldn`t entirely rule out a rumble of thunder or two. && .SHORT TERM...(Sunday through Tuesday) Issued at 349 PM EDT Sat Jun 23 2018 ...Active weather pattern continues... High Impact Weather Potential: Possible thunder Tuesday. Pattern Synopsis/Forecast: A more active weather pattern continues. Heavy rain is forecast south of M-55 with a shortwave over lower Michigan. This may produce an additional 0.25 to 0.50" (locally higher) than what falls during the overnight hours. Will have to keep an eye out for any flooding threats. The rest of northern lower will see lingering shower chances throughout the day...before finally diminishing Sunday evening/night as high pressure centered over Hudson Bay builds into northern Michigan along with much drier air and aforementioned shortwave departs to the southeast. This high pressure will diminish cloud cover from north to south beginning Sunday night and provide a mostly clear and pleasant Monday afternoon. Clouds will be on the increase once again Tuesday as a low pressure system over the the central Great Plains brings our next chances of rain Tuesday through Wednesday as it tracks through the northern Great Lakes. Thunder chances will increase throughout the day Tuesday as the warm front associated with the aforementioned low pressure system provides some additional lift. Have thunder in the forecast, but not too impressed with the bulk shear values (only in the realm of 20-30kts). Best chances will be during the late evening into Wednesday as a southwesterly low-mid level jet forms ahead of the cold front associated with said system, along with increasing ingredients for thunderstorm development. A fairly light wind regime will remain throughout the forecast period. Highs Sunday through Tuesday will reach into the 70s, while lows will drop into the upper 40s to low 50s. .LONG TERM...(Tuesday night through Saturday) Issued at 349 PM EDT Sat Jun 23 2018 High Impact Weather Potential: Possible Storms Tuesday night into Wednesday. A shortwave moving in from the Northern Plains will support showers and storms Tuesday into Wednesday. Some deep moisture and instability have the potential to line up over the region, but whether or not the best shear/support is in the right place at the right time remains to be seen. As the frontal boundary sweeps through the region on Wednesday, showers and thunderstorm chances should diminish late in the day. A ridge starts to build into the area late in the week, allowing temperatures to climb and stay above normal to end the workweek. && .AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon) Issued at 200 PM EDT Sat Jun 23 2018 IFR ceilings will gradually shrink in coverage as afternoon heating develops, but MVFR will still be fairly widespread. Also some stubborn BR holding on at APN with IFR visibilities expected for the next few hours. Latest radar and satellite imagery show showers and widespread cloud cover starting to slowly diminish, but some additional light showers (perhaps a rumble of thunder) may develop near TVC/MBL later this afternoon. A fairly strong disturbance will cross northern Lower overnight. With lingering abundant low level moisture, this will likely lead to more widespread/heavier shower activity after 06Z. MBL and TVC will be most impacted by any heavier rainfall. MVFR to IFR cigs are likely once again, with some visibility restrictions from heavier rainfall. APN is likely to be impacted by some additional BR overnight. Shower chances diminish through the day Sunday with cigs slowly improving towards afternoon. Winds will remain light (< 10 knots) through the period. && .MARINE... Issued at 349 PM EDT Sat Jun 23 2018 Winds and waves will remain below SCA criteria through the remainder of the weekend. Rain chances will remain for most of our nearshore areas over Lake Huron today through Sunday as an area of low pressure meanders over the Great Lakes. Lake Michigan may see some rain showers tonight through Sunday morning. Do not expect any thunderstorm activity thru the weekend. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JPB NEAR TERM...MK SHORT TERM...TL LONG TERM...STJ AVIATION...MK MARINE...TL
Area Forecast Discussion
National Weather Service La Crosse WI
623 PM CDT Sat Jun 23 2018 .SHORT TERM...(Tonight through Sunday Night) Issued at 205 PM CDT Sat Jun 23 2018 Partly sunny skies prevailed across the region this afternoon. Temperatures were in the middle 70s to lower 80s. For tonight and Sunday, there is still a lot of uncertainty in timing and location of precipitation chances. Models do show a weak disturbance moving across the area on Sunday which could trigger shower activity along with a small chance of thunderstorms. Per coordination with surrounding offices, slowed down the chances of rain until very late tonight, and more likely Sunday morning. The GFS/Canadian are more aggressive with rainfall totals while the ECMWF indicated the lowest rainfall totals during the day Sunday which gives uncertainty in rainfall amounts and actual coverage of showers. Based on the latest model trends, highest chances of rain will be across southeast Minnesota, northeast Iowa and southwest Wisconsin north of Interstate 90. Took a blend of model guidance for lows tonight similar to the trends of last night although slightly warmer in spots. Did not stray far from guidance for highs on Sunday. Shower/slight thunderstorm chances shift westward Sunday night as better moisture transport redirects across central IA into southwest MN. .LONG TERM...(Monday through Saturday) Issued at 205 PM CDT Sat Jun 23 2018 Main concern through this period will be heavy rain/severe potential mainly Monday night into Tuesday as a vigorous mid-level closed low/surface low rotates northeast through the area. NAM/GFS models in good agreement with increasing feed of moisture transport into the area which is maximized Monday night into early Tuesday morning with noctural 850mb jet. As a result, precipitable water values increase into the 1.5-2 inch range Tuesday. CAPE and bulk shear will depend on track of the mid-level low. NAM keeps higher CAPE pool south of I-90 while the GFS brings in a respectable n/s corridor of 2-3KJ/Kg across the entire area along with bulk shear in the 20-40Kt range (mainly south of I-90). So, will definitely have to keep an eye on heavy rain and severe thunderstorm potential for this time frame. Wednesday is looking dry at this point as a ridge of high pressure builds over the area. Thursday through Saturday could be active as several convective complexes make their way out of the Plains and over the ridge into our area. Bulk of this activity looks like it would be along and north of I-94. Otherwise, look for high through the period well into the 80s. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 623 PM CDT Sat Jun 23 2018 A few showers have developed late this afternoon as a weak short wave trough moves across Iowa. Very limited instability in place with maybe 750 J/kg of MUCAPE, but enough that there could be a rumble of thunder. The showers are drifting slowly to the southeast and will include a VCSH at KRST for a couple of hours until the instability dissipates with the loss of daytime heating. After that, some concern again for fog in the river valleys. The cloud cover should diminish overnight but expecting some clouds to remain for much of the night. Light winds again through a deep layer will be favorable for formation but the 23.18Z NAM and 23.21Z RAP do not show saturation occurring at the surface. For now, will not include any mention of fog and will monitor trends through the evening for possible inclusion with later forecasts. Another small chance for some showers Sunday afternoon west of the Mississippi River as a short wave drifts into central Minnesota and will maintain the VCSH at KRST. && .HYDROLOGY... Issued at 205 PM CDT Sat Jun 23 2018 Area rivers continue to run higher than normal with some minor flooding occurring or forecast to occur in places. Concern is there for the possibility of more flooding heading into next week. A vigorous storm system rotating through the region Monday night through Tuesday night may have the biggest impact as precipitable water values increase into the 1.5-2 inch range. This could translate into pockets of very heavy rainfall which could lead to some flooding. Will be keeping a close eye on the evolution of this system. Wednesday looks dry but then there is the potential for several convective complex to rumble through the area Thursday through Saturday. This keeps the concern for flooding notched up a bit. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...RE/DAS LONG TERM...DAS AVIATION...04 HYDROLOGY...DAS
Area Forecast Discussion
National Weather Service Birmingham AL
939 PM CDT Sat Jun 23 2018 .UPDATE... Evening Update. && .SHORT TERM... Canceled the Tornado Watch just slightly early as the convection has decreased significantly in intensity and coverage. With the loss of daytime insolation, temperatures have fallen allowing some CIN to form. With very limited surface convergence, not expecting much additional development overnight. Adjusted rain chances and bumped them northward the remainder of the overnight hours. 75 Previous short-term discussion: Several rotating storms have developed over areas from Vernon to Double Springs. These storms will continue eastward the next few hours with damaging winds, quarter size hail and a tornado possible. The rotation has been well entrenched in the mid levels and have not seen too much evidence of any lowering. It appears that low level winds and convergence are weaker and the rotation is having a very hard time building down. LCL`s do lower in northern areas and we are also entering times just after sunset where it typically goes down. Bulk Shear values are around 30kts, so some organization is possible. This value is lower than yesterday under nearly the same environmental parameters. Effective helicity values are around 200, and as evidenced, rotation is taking place. A mid level disturbance is moving over the region and helping ignite this activity. Will monitor these storms closely the next few hours and expect a decrease by mid evening. 75 Previous short-term discussion: Through early this evening. We`re continuing to re-evaluate the forecast for this afternoon and evening in terms of the severe weather potential across Central Alabama. Earlier activity from the previous MCS has weakened considerably, with the leftover outflow boundary now pushing into Chambers and Lee County. Behind that cold pool lies a much more stable airmass, and many locations remain in the 70s. However, clouds are quickly trying to clear enough for some daytime heating. We`re now at 82 degrees here at the Shelby County Airport. Meanwhile, locations farther south and west that were unaffected by the MCS this morning are already quite warm into the upper 80s. As the severe threat ends across the far northeast counties through the early afternoon hours, we`ll continue to watch additional development to our west. Large outflow boundaries from previous convection are racing our direction from Mississippi and Arkansas. Those boundaries may trigger additional convection this afternoon within areas that will be very unstable. RAP forecasts are pointing at 3000-4000 J/KG of SB CAPE building into at least our far western/southwestern counties by late this afternoon. However, the RAP is currently not doing a good job of taking into account the large subsidence zone that`s currently in place. It`s also unclear if we`ll have enough lift by those outflow boundaries moving in from the west to trigger those storms. The HRRR and other mesoscale guidance is starting to hint at more development following almost no development a few hours ago. Therefore, much uncertainty remains in today`s severe weather forecast. For now, will leave our current forecast as-is with the potential for additional development. Based on additional guidance and observation trends this afternoon, we`ll likely be updating our severe threat graphic by 4pm. Damaging straight-line winds will remain the greatest hazard. 56/GDG .LONG TERM... Sunday through Friday. Height rises on Sunday should lead to hotter conditions and very minimal prospects for rainfall. The upper-level ridge should continue to limit rain chances on Monday and Tuesday, but isolated convection cannot be ruled out. The ridge may weaken on Wednesday as a trough moves through the Great Lakes and Ohio Valley. There is good model support for a weak shortwave near the base of the trough over the Tennessee Valley which would lead to enhanced rain chances. This features may end up getting pulled south and west across the forecast area on Thursday and Friday as ridge develops to our north. This scenario would lead to a continuation of somewhat enhanced rain chances. 87/Grantham && .AVIATION... 00Z TAF Discussion. Next upper level disturbance was entering western Alabama and kicking off a few thunderstorms. These storms will have the potential of producing some gusty winds, a tornado and frequent lightning. At this time, the storms are expected to diminish by around 10 pm. but not completely go away. Added a mention of VCTS at TCL/BHM and have skipped all other terminals. High pressure builds over the region on Sunday and shower/storm chances go way down. Will not mention any convection for Sunday but an isolated storm is possible with chances only about 10 percent. MVFR ceilings are possible again overnight. The best chance will be south and have clouds around 015 after 06z. Northern areas was not quite as confident but have a tempo group of ceilings at 025. Ceilings rise and thin by 15-16z and southwest winds continue at 8kts or so. 75 && .FIRE WEATHER... High rain chances will continue for today especially across the northern third of the area. Patchy fog may develop in the overnight and early morning hours where rainfall occurs. Rainfall is not expected on Sunday as a suppressive ridge develops. There are no fire weather concerns at this time. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 69 91 71 92 71 / 40 10 10 30 10 Anniston 69 91 72 93 72 / 20 10 10 30 20 Birmingham 73 93 74 94 74 / 30 10 10 30 10 Tuscaloosa 74 95 74 95 74 / 10 10 10 30 10 Calera 73 92 73 93 73 / 20 10 10 30 20 Auburn 72 91 73 92 74 / 10 10 10 30 20 Montgomery 73 93 75 94 75 / 10 10 10 30 20 Troy 74 92 73 93 74 / 0 10 10 30 20 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$
Area Forecast Discussion
National Weather Service Burlington VT
730 PM EDT Sat Jun 23 2018 .SYNOPSIS... Deeper moisture will linger over the North Country tonight with plenty of cloud cover...the threat of some showers...and patchy fog. We will lose the fog Sunday morning but expect plenty of clouds and occasional showers as a trough of low pressure moves into the region. Eventually the trough moves east of the region on Monday with drier air returning to the area Monday into Tuesday as high pressure builds in. Temperatures will be returning to seasonal normals during this time period as well. && .NEAR TERM /THROUGH SUNDAY NIGHT/... As of 730 PM EDT Saturday...Opted to adjust PoPs somewhat downward overnight from a area-wide perspective, generally into the 20-40% range. Latest WV imagery showing weak shortwave tracking across the southern tier of NY as of early evening. Progs suggest this feature will swing through the area later this evening but with areal shower coverage scattered at best with many spots remaining largely dry overnight outside a passing sprinkle. HRRR output seems to have the best handle on this evolution so leaned in its direction accordingly. Cloudy skies certainly the rule with weak low level blocked flow and decent boundary layer RH, which suggests more of a low stratus- type night as opposed to fog. As such, have adjusted areal coverage of any real fog to elevations generally above 1000-1500 feet which have higher probabilities to lie within the cloud layer itself. The rest of the forecast in regard to winds and temperatures etc. remains on track. Have a great evening. Prior discussion... On Sunday we will see a somewhat similar scenario to Saturday. After any fog burns off early Sunday we will still have plenty of clouds around and as an upper trough moves into the region...we should see showers flare up again. Not a complete washout but periods of showers throughout the day...especially in the afternoon. Highs will be in the upper 60s to the mid 70s. Showers will begin to end from west to east Sunday night as the upper trough slowly moves east of the region. Any showers will mainly be across Vermont along with the most cloud cover. Lows will generally be in the 50s. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... As of 410 PM EDT Saturday...North to northwest flow aloft will remain over the area through much of this period. As a result...complete clearing will be a slow process and there could still be some showers around on Monday...especially over eastern Vermont as one last shortwave drops down into the base of the upper trough as it is exiting Vermont. Generally keeping precipitation chances in the slight chance range. Highs will be in the upper 60s to mid 70s. More pronounced clearing takes place Monday night with high pressure building in. Lows will generally be in the 40s to lower 50s with some upper 30s in the mountains. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 410 PM EDT Saturday...Quiet weather is expected for the first part of the extended with sfc high pressure building in behind a departing low pressure system to the east. High temps Tuesday will be right around normal in the upper 70s to around 80. Lows Tuesday night will provide good sleeping weather with temps in the mid to low 50s with minimal humidity. Clouds will begin to increase overnight Tuesday into Wednesday ahead of our next system approaching from the west. New 12z Euro guidance has sped things up by a few hours with precip over- spreading VT by 00z Thursday, but have trended closer towards 00Z Euro and 12z GFS with the idea of showers making their way into the St. Lawrence valley towards 00z Thursday and moving eastward through the overnight hours...with drier air in place at sfc, initial precip may not reach the ground. Additionally, can`t rule out a rumble of thunder across St. Lawrence valley with some minor instability present, so have mention of slight chance of thunder in the grids for points W of Adirondacks. As sfc low pressure tracks slowly northeastward of international border, precip will be slow to exit the area during the day Thursday. With a weak disturbance passing along the international border behind the main shortwave Thursday night have also kept some lingering slight chance of showers and clouds in the grids through 12z Friday. After this system, our attention turns towards a potential heatwave kicking off the second weekend of summer. Models are in good agreement on a subtropical ridge over the eastern US towards the end of next week with both GFS and Euro showing near 595dm thicknesses positioned across the Mid-Atlantic/New England on Saturday. Initial 925 temps between 24-27C suggest high temperatures in the mid to upper 90s but right now haven`t gone completely bullish on high temps for Friday/Saturday...have adjusted Superblend temps up a few degrees just to show warming trend. At this time, Friday/Saturday highs are in the upper 80s Friday/low 90s Saturday but may need to adjust up more as we get closer. Lows through this period will also be significantly above normal with temps Friday/Saturday night in the upper 60s to low 70s. Chances of precipitation look minimal Friday/Saturday due to mid-level subsidence however have mention of slight chance of thunderstorms in the grids...should anything develop this warm environment will be conducive to producing thunder. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... Through 00Z Monday...Widespread MVFR and light winds through much of the forecast period with scattered IFR overnight and higher terrain obscured. Highest probs for IFR to occur at KSLK and KRUT in the 06-13Z time frame. After 18Z Sunday some slow improvement in cigs expected, especially at KMSS/KPBG/KBTV where the forecast will show levels lifting to VFR. In terms of precipitation widely scattered showers will traverse the area through the period with best coverage overnight and again after 18Z on Sunday. Widely scattered to scattered nature of coverage warrants only VCSH at this point however. Outlook... Sunday Night: Mainly VFR, with local IFR possible. Chance SHRA. Monday: Mainly VFR, with local MVFR possible. Slight chance SHRA. Monday Night: VFR. NO SIG WX. Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. NO SIG WX. Wednesday: VFR. Chance SHRA. Wednesday Night: MVFR. Likely SHRA, Slight chance TSRA. Thursday: MVFR. Chance SHRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Evenson NEAR TERM...JMG/Evenson SHORT TERM...Evenson LONG TERM...Banacos/LaRocca AVIATION...JMG
Area Forecast Discussion...Updated
National Weather Service Billings MT
855 PM MDT Sat Jun 23 2018 .UPDATE... Precipitation had remained generally isolated to scattered through the evening as the upper low moved through the area. Some storms likely produced heavy rainfall based on PW`s close to an inch and the high reflectivities seen on radar. As of 0245Z, there were a few dying echoes in the far E, a cluster of showers and isolated thunderstorms over S. Big Horn and Sheridan Counties, and other showers over Wheatland County. CAMS models had varying placement of generally isolated showers/thunderstorms tonight, so went with radar trends for early tonight, then blended with CONSShort, which gave isolated PoPs overnight for most of the area, and scattered PoPs over S. Big Horn/Sheridan Counties under track of the low with it`s vorticity. RAP soundings were stable after 06Z across the area, so removed thunder overnight. Adjusted sky cover and winds based on current trends. Not concerned about fog as there will be a fair amount of cloudiness overnight. Other forecast parameters looked good. The low will shift E into SD/NE during Sunday and an inverted trough will keep a good chance of precipitation over the eastern zones. Arthur && .SHORT TERM...valid for Sun and Mon... Upper trough over western Montana will drop southeast into NE Wyoming by Sunday morning. This will create enough instability and broad ascent to support isolated to scattered showers and thunderstorms through Sunday evening. We may also see some snow showers over the higher elevations tonight, including the Beartooth Pass. EBS (effective bulk shear) is not very impressive so we are generally expecting garden variety thunderstorms through the rest of the weekend with small hail and perhaps brief heavy rainfall. The upper low moves off to the east by Monday with some ridging and drying over most of our CWA. Some risk of storms will linger along the Montana/Dakota border Monday afternoon. Highs Monday will push well into the 80s for most areas. The main adjustments for this package were to lean the highest PoP`s more toward the east Sunday as the latest progged QPF suggest more widespread precipitation to our eastern counties. This makes some sense as latest models have the upper low a little further east than previous runs. BT .LONG TERM...valid for Tue...Wed...Thu...Fri...Sat... The extended did not have many changes with the latest guidance. Tuesday still has a weak cold front move through the area. While the models do not generate much QPF, have generally kept PoPs the same. Given the moisture in the area cannot rule out there being more activity than the models are project. Thursday looks to be dry ahead of the next trough starting to work into the area Friday. In general the models continue to show another active pattern as a low drops down into the Northern Rockies. It still looks like there could be some decent rainfall amounts again with this next weekend. Reimer && .AVIATION... Isolated showers and a few evening thunderstorms will bring local MVFR to IFR conditions due to heavy rainfall. Occasional mountain obscuration can be expected through tomorrow morning. Otherwise VFR conditions will prevail tonight. Chambers && .PRELIMINARY POINT TEMP/POPS... Sun Mon Tue Wed Thu Fri Sat ----------------------------------------------------------- BIL 054/074 056/085 060/078 055/082 057/080 055/074 054/072 24/T 21/U 12/T 20/U 12/T 43/T 44/T LVM 049/072 049/084 055/077 047/080 050/079 049/071 047/068 22/T 10/U 12/T 20/U 12/T 43/T 44/T HDN 054/074 054/085 058/079 054/083 056/082 055/076 053/074 25/T 31/U 12/T 20/U 12/T 43/T 44/T MLS 058/075 058/082 061/081 055/081 059/083 058/077 056/074 26/T 31/U 12/T 20/U 12/T 43/T 44/T 4BQ 056/072 056/080 058/083 055/083 058/084 057/077 056/076 26/T 42/W 11/U 20/U 12/T 33/T 54/T BHK 055/073 056/077 057/083 053/080 056/082 055/076 054/075 26/T 42/T 11/U 20/U 12/T 44/T 45/T SHR 052/069 051/080 056/080 052/082 055/082 053/075 050/074 65/T 31/U 11/U 20/U 12/T 33/T 44/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$
Area Forecast Discussion
National Weather Service Cheyenne WY
227 PM MDT Sat Jun 23 2018 .SHORT TERM...(This evening through Monday night) Issued at 225 PM MDT Sat Jun 23 2018 Scattered showers and a few storms developing over northwest parts of the CWA ahead of the next upper low evident on satellite over western Montana. Expect convection to continue to increase through this evening as the upper low moves towards the CWA overnight. Some potential for heavy rainfall exists especially over northern parts so the current flood watch looks fine. Rain may taper off some later tonight as suggested by the HRRR but should increase again Sunday as the upper low drifts slowly east into western Nebraska. Instability not too high Sunday/ CAPES about 500-900 J/kg over the NE Panhandle/ and latest SPC outlook has slipped the Slight risk east of the CWA but a few stronger storms still may occur over the NE Panhandle. Locally heavy rainfall still possible with stronger storms. The upper low will continue to drift slowly eastward Sunday night and Monday with showers and a few storms persisting over the NE Panhandle in wrap-around flow. Monday night looks dry with clearing skies. .LONG TERM...(Tuesday through Saturday) Issued at 225 PM MDT Sat Jun 23 2018 Some changes gleaned from the 12Z medium range models/ensembles. Northwest flow aloft downstream of upper ridge early Tuesday becomes zonal as shortwave energy translates east across far southern Canada through Wednesday night. Flow aloft backs to the southwest as a upper trough deepens over the northwest CONUS Thursday and Friday. The GFS is deeper/slower than the ECMWF with this trough. A weak surface front slips southward into the high plains Wednesday and stalls along the Laramie Range Wednesday night. No convection is forecast with this boundary, which shifts northward as a warm front Thursday. This front again drifts southward with the passage of a shortwave across the Dakotas. Isolated convection is possible Thursday evening north and east of a line from Douglas to Scottsbluff. A low pressure system develops over northern WY Friday and tracks to the east in SD Friday night, with front sagging south into portions of eastern WY and northern NE. Isolated to scattered convection may develop as far south as Wheatland, Scottsbluff and Alliance Friday night and Saturday. Above normal temperatures will prevail through the long term with highs in the 80s to mid 90s Tuesday and Thursday, and 80s Wednesday, Friday and Saturday. && .AVIATION...(For the 18Z TAFS through 18Z Sunday morning) Issued at 1155 AM MDT Sat Jun 23 2018 Generally VFR. Scattered showers and thunderstorms will develop this afternoon, becoming more numerous this evening. Onset will be between 20Z and 23Z in southeast WY, and after 23Z in western NE Panhandle. Brief gusty/erratic winds, moderate turbulence and small hail will accompany the stronger convection along and east of I-25. TSRA will weaken to SHRA later this evening. Winds will shift to northerly as a cold front passes through this evening. && .FIRE WEATHER... Issued at 225 PM MDT Sat Jun 23 2018 A low pressure system in the upper atmosphere will move across the area through Sunday bringing widespread showers and thunderstorms, with wetting rainfall in many areas. Heavy rainfall is possible, especially over northern districts. The low pressure system will move east of the area Sunday night and Monday with rain coming to and end. Warmer and mainly dry weather is expected by midweek. && .HYDROLOGY... Issued at 225 PM MDT Sat Jun 23 2018 Scattered to numerous showers and thunderstorms will develop this afternoon and evening across southeastern Wyoming and the western Nebraska Panhandle. 700 mb mixing ratios over 7 g/kg will be more than adequate for heavy rainfall with the stronger cells, with accumulations over an inch through Sunday evening. Although storm motion will not be particularly slow, training storms and already saturated ground may cause localized flooding across the flood watch area. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Flood Watch from 6 PM MDT this evening through Sunday evening for WYZ101>103. NE...None. && $$ SHORT TERM...RE LONG TERM...MAJ AVIATION...MAJ FIRE WEATHER...RE HYDROLOGY...MAJ/ADL
Area Forecast Discussion
National Weather Service Grand Forks ND
950 PM CDT Sat Jun 23 2018 .UPDATE... Issued at 946 PM CDT Sat Jun 23 2018 Convection continuing this evening along an east to west corridor between Fargo and Grand Forks. Strength and coverage are decreasing as lightning levels and cloud tops are less intense over the past hour than earlier this evening. Activity will be mostly finished by midnight as this rate with a few isolated showers possible through the overnight mainly in the south valley. && .SHORT TERM...(This evening through Sunday) Issued at 309 PM CDT Sat Jun 23 2018 Showers and thunderstorms, their strength and coverage, will be the main issue for the period. Water vapor loop and rotation of the radar returns shows the main upper low is still to our southwest over south central ND/north central SD. There has been thunderstorm activity developing during the early afternoon hours across a couple of old boundaries. One lingering front in the Lake of the Woods area has created enough surface convergence for some slow moving thunderstorms. Another surface boundary stretching from the Devils Lake basin in to west central Minnesota has been the focus for additional thunderstorm development, with the greater coverage on the ND side. SPC meso page has a non-supercell tornado parameter around 4, and low level CAPE and surface vorticity are maxed out in that area. Surface vorticity is much weaker with the cells down in west central MN. Will have to keep a close eye for any funnel formation during the next few hours, but the RAP has the best vorticity moving away from the highest low level CAPE values by 21-23Z. The loss of daytime heating will reduce coverage of showers and thunderstorms as we head into the overnight hours. However, the weakening upper low will still be drifting eastward into the area and many of the high resolution models have lingering convective activity hanging around into 06Z and beyond. Best chances will be near the surface low in northeastern SD, so have some chance POPs lingering in our south and west with more isolated activity elsewhere. Temps should drop into the 60s overnight with at least some clearing. By tomorrow, the eastern upper low over our region will have weakened and merged with the western circulation moving from the Northern Rockies into the Northern Plains. More showers and thunderstorms will develop again by afternoon thanks to daytime heating, with the best chances in the southwest closest to the upper system. It looks to be a another day with decent instability (around 1000 J/kg of CAPE), but weak deep layer bulk shear. Temperatures should be a couple of degrees cooler than today thanks to cloud cover. .LONG TERM...(Sunday night through Saturday) Issued at 309 PM CDT Sat Jun 23 2018 Deepening upper low caught on the southern limb of split flow will slide to the south and east of the region Sunday through Tuesday. This will keep rain chances within the forecast Monday and Tuesday will keeping temperatures mild and skies cloudy. Areas that hold best chances for rain reside in the southern Red River Valley into west-central Minnesota. Thunderstorm chances Monday will be limited on these days due to clouds hindering diurnal destabilization and weak mid level lapse rates. A cold front slowly approaches from the west late Tuesday into Wednesday bringing the chance for scattered showers and thunderstorms. By mid week zonal flow aloft will set up transitioning to southwesterly flow towards late week. This will allow thunderstorm chances and the temperature trend to increase late next week. Surface high pressure behind Wednesday`s stalling cold front should keep conditions dry for at least one day, progged to be Thursday. This is short lived as southwesterly flow aloft will swing embedded disturbances over the Northern Plains. There may be an uptick in strong to severe thunderstorm chances late next week as better wind shear associated with the aforementioned embedded disturbances develops over the Northern Plains along with the chance for instabiility and moisture content to grow over the area. A number of factors including frontal placement and shortwave passage timing will prevent any further details from being forecast at this time. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 641 PM CDT Sat Jun 23 2018 Widespread convection will continue across the area this evening. Light winds will persist through the TAF period with more showers and thunderstorms tomorrow. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...JK SHORT TERM...JR LONG TERM...CJ AVIATION...JK
Area Forecast Discussion
National Weather Service Wichita KS
928 PM CDT Sat Jun 23 2018 .UPDATE... Issued at 925 PM CDT Sat Jun 23 2018 Convective evolution remains a challenge overnight and on Sunday. Per radar trends so far this evening, HRRR seems to be on the right track. 0000 UTC surface/raobs show band of richer/deeper moisture across southwest half of OK, pointing into far western KS. This bodes well for HRRR idea of western KS convection continuing to track southeast with the west-north west flow aloft. The main issue is how far east the precipitation will go. HRRR pushes precipitation all the way into southeast KS by mid morning. This seems to be a stretch, given HRRR tendencies this past week, but possible if 850MB flow veers. This complicates forecast for Sunday, as HRRR breaks out a band of altocumulus castellanus and showers in the elevated baroclinic zone over the Flint Hills, while keeping the low level moisture/thermal gradient well west of of the forecast area throughout the afternoon. This would significantly delay the onset of robust convection in the forecast area. Adjusted overnight forecast for now to increase the chance of rain, and will let the mid shift watch trends overnight and make adjustments to the Sunday afternoon-evening periods after perusing the entire 0000 UTC model suite. -Howerton && .SHORT TERM...(This evening through Tuesday night) Issued at 405 PM CDT Sat Jun 23 2018 The main forecast concerns will be severe weather potential Sunday into Sunday night. Will maintain slight chances (20-30%) of thunderstorms tonight into Sunday morning. This would be for the possibility of a storm cluster or two propagating east-southeastward off of the High Plains, along with strengthening 850-700 warm air advection and moisture transport. The HRRR, 18z NAM-WRF, 12z GFS models are more aggressive with this initial convective potential in comparison to some of the other high resolution models. Strong/gusty winds would be the main threat with any of these storm clusters. If this convection is more widespread and lingers well into Sunday morning, possible outflow effects will make overall convective evolution into Sunday afternoon/night much more uncertain and challenging. A strong shortwave trough will move out of the northern Rockies over the Central Plains Sunday into Monday. A 40-50 knot southwesterly mid-level jet streak will accompany this trough as it moves out over Kansas. Barring widespread convective outflow effects (mentioned above) materializing, a very moist and strongly unstable airmass (MLCAPE of around 4,000 J/KG) and 35-40 knots of deep layer shear will be in place ahead of the approaching cold front. Most short- range models indicate storms developing on the cold front over the central High Plains by midday Sunday, then traversing southeastward Sunday afternoon into Sunday night. These storms should propagate southeastward into central/south-central Kansas counties Sunday afternoon or evening with upscale growth into one or more damaging MCS`s. The main threats Sunday afternoon/night appear to be widespread damaging winds, with high-end severe gusts possible. A few large to very large hail reports are possible mainly Sunday afternoon. Strong 850 mb moisture transport and upper divergent flow will support the potential for thunderstorms across much of the forecast area Sunday night. Anomalously high precipitable water will support locally heavy rainfall/flooding, and strong to severe wind gusts with storms Sunday night. Will maintain a chance of thunderstorms Monday into Monday night across eastern Kansas, however this will strongly depend on where the effective front/boundary ends up due to outflow effects from widespread storms Sunday night. A few strong to marginally severe storms will be possible. .LONG TERM...(Wednesday through Saturday) Issued at 405 PM CDT Sat Jun 23 2018 Confidence is high in above normal temperatures given the large scale upper pattern agreement with the GEFS and EPS medium range guidance. Upper ridge development is progged over the south-central Plains Wednesday into Thursday, before sliding over the eastern/southeastern CONUS by Friday/Saturday. Mean upper troughing will develop over the western states. Resultant lee troughing will allow for breezy southerly winds and hot and humid weather across the forecast area for mid to late week. High temperatures will likely approach or exceed the century mark by a few degrees across central/south-central Kansas, with lower-middle 90s in the southeast. Balmy overnight lows in the 70s are expected. Peak afternoon heat indices of 100-105 are projected. Residual chances of thunderstorms could linger mainly over northeast Kansas Tuesday into Tuesday evening, otherwise rain chances from Wednesday through Saturday look slim to nil. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 640 PM CDT Sat Jun 23 2018 Convective evolution will be the main concern throughout the period. Track of current storms in northwest KS problematic, with a plethora of model solutions from which to choose. Would appear that storms will turn to a more southerly track with onset of low level jet. HRRR which seems to be handling ongoing storms best, breaks out precipitation in moisture warm air advection on eastern side of outflow boundary around 0900 UTC over the Flint Hills. Course this is dependent on size and track of initial complex. All of this then compounds what happens on Sunday with timing and magnitude of storms. For now, have kept near term part of the forecast dry, with some VCTS near end of the period at KGBD, KRSL and KSLN. Confidence in forecast is low. -Howerton && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 70 91 69 88 / 50 60 80 20 Hutchinson 69 90 67 88 / 40 80 80 20 Newton 69 89 67 87 / 30 70 80 20 ElDorado 69 88 68 86 / 40 50 70 30 Winfield-KWLD 69 90 70 88 / 40 30 60 40 Russell 68 86 64 88 / 30 70 70 10 Great Bend 68 87 64 88 / 30 80 70 10 Salina 70 89 68 89 / 20 80 80 20 McPherson 69 89 67 87 / 30 80 80 20 Coffeyville 70 89 72 89 / 30 20 50 50 Chanute 69 88 70 86 / 20 30 60 50 Iola 69 88 70 85 / 20 30 60 40 Parsons-KPPF 71 89 71 88 / 30 20 60 50 && .ICT WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...PJH SHORT TERM...JMC LONG TERM...JMC AVIATION...PJH
Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
1027 PM CDT Sat Jun 23 2018 .UPDATE... The thunderstorm activity that brushed the southern Rolling Plains this evening has shifted to the south and east, so we`ve lowered PoPs below mention for the remainder of the night. && .PREV DISCUSSION... /issued 630 PM CDT Sat Jun 23 2018/ AVIATION... Isolated to widely scattered thunderstorms currently developing from southwest Oklahoma south-southwestward into the eastern Permian Basin should remain south and east of the terminals this evening. Even so, thunderstorms currently expanding in eastern Colorado will likely form into a complex and track southeastward into Oklahoma late tonight (early Sunday morning). Outflow from these storms could briefly move through the terminals toward dawn Sunday. If this happens a period of breezy northeasterly winds will be possible, along with a threat for sub-VFR stratus. This is far from certain, but certainly possible. Otherwise, relatively light southeasterly winds this evening will yield to breezy southerly winds Sunday afternoon, with VFR prevailing. PREV DISCUSSION... /issued 250 PM CDT Sat Jun 23 2018/ DISCUSSION... The cold front has drifted to our southern zones and is expected to retreat northward later tonight as a surface low develops across northeastern NM/southeastern CO ahead of an upper low that will dig southward from MT. Models are hinting at some showers and thunderstorms possibly developing along the Rolling Plains as the front retreats. The likely area would be the southern Rolling Plains as shown by the HRRR as the best convergence will be located in that region of the FA. Surface winds will be out of the south tomorrow ahead of another approaching front and will allow highs to reach above the century mark. Monday will be almost 10 degrees cooler thanks to the front. The front will retreat late Monday into early Tuesday as upper ridging begins to push into the region. Models continue to show some convective development along the front late Monday as it retreats and a shortwave moves over the region. Given the small scale of the shortwave pops will continue to be on the low end of mentionable. Upper ridging will dominate the region from Tuesday into late week. The GFS and ECMWF have started to line up on their weekend forecast by having the upper ridge push eastward by Saturday while amplifying an upper trough across the western CONUS. This may allow for the weekend to be somewhat wet with dryline convection supplied by Pacific moisture. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 33
Area Forecast Discussion
National Weather Service Little Rock AR
908 PM CDT Sat Jun 23 2018 .UPDATE... Latest subjective surface analysis indicates a boundary from near Pine Bluff, then extending westward to near Atoka Oklahoma. A few cells have attempted to develop along this feature during the past 45 minutes. The boundary will move northward overnight, and is expected to provide a focus for widely scattered convective development overnight. Also, will need to monitor MCS activity, currently developing across the central high plains. Forecast storm motion vectors indicate this activity will approach western sections towards sunrise. 55 && .PREV DISCUSSION...(ISSUED 624 PM CDT Sat Jun 23 2018) AVIATION... As previously mentioned, forecasts of convective development are complicated during the short term. A southerly surface wind of <=9 kts will prevail during the second half of the forecast period. 55 PREV DISCUSSION...(ISSUED 341 PM CDT Sat Jun 23 2018) SYNOPSIS... A complex forecast is evolving this afternoon, with the potential for severe thunderstorms late this evening through the overnight hours. While confidence in storms developing is low, if they do materialize, damaging winds, isolated tornadoes, and torrential rainfall will all be possible. The greatest risk appears to exist across portions of central and northern Arkansas. SHORT TERM...Today Through Monday Unfortunately, concrete details pertaining to the forecast through tomorrow morning remain elusive as a complex convective scenario continues evolving. 19Z objective analysis highlights a favorable synoptic pattern, characterized by broad mid-level troughing across the central CONUS and surface troughing stretching from West TX northeastward into southern OK. A belt of enhanced moisture at H850 stretches roughly west-to-east from the TX Panhandle to near Memphis, TN and is generally juxtaposed with a broad area of deep layer moisture flux convergence and lower boundary layer confluent flow. Throughout the morning, light showers have persisted where these subtle forcing mechanisms have been favorably overlapped; although radar trends indicate a decrease in precip over the last hour or so, likely due to dry air entrainment near the OK/AR border. At the surface, two fairly distinct boundaries were noted as of early afternoon: a convectively-reinforced warm front stretching from southwestern OK eastward into TN, and the aforementioned west- to-east oriented confluence axis from western OK through central AR. The overall PoP fields and severe risk are heavily predicated on how these features evolve this afternoon, and this remains a major point of contention with the going forecast. The current thinking has the warm front gradually lifting north into central and perhaps northern AR late this evening, after which the boundary should become quasi- stationary and will act to focus any convection that manages to develop. An additional point of contention is the timing of an approaching upper impulse noted on WV imagery. 19Z analysis places the impulse across southern OK with the expectation it will eject across the area this evening and overnight. The additional forcing it provides could be enough to initiate convection, but it remains unclear how favorable the timing of this approaching impulse will be with respect to other key features, namely frontal timing/position. Model guidance has offered little more than frustration so far today, with the HRRR entirely out to lunch and questionable consistency among other model solutions, although the going trend is for less convective coverage or, more frustratingly, a failure for convection to initiate. The NAM/NAMNEST have remained most insistent in generating convection across west-central AR after 00Z this evening, with storms overspreading northern AR in the 06-12Z time frame. Other solutions have trended toward less convective coverage or, more frustratingly, no convective initiation at all. Not ready to wipe out PoPs altogether, so gave heavy preference to the RAP given its relatively decent grasp on hourly trends. Incorporating its solution with the remaining body of evidence yields lower- confidence PoPs, initially across central AR, and shifting into northern AR overnight. The timing and placement of PoPs was generally tied to the position of the surface warm front as well as a notable area of deformation and moisture axis aloft. If convection can initiate, the overall environment will certainly be supportive of severe storms overnight, with MLCAPE values on the order of 3000 J/kg and over 1000 J/kg of DCAPE. Deep shear values around 30 kts should promote minimal organization, although an overall lack of significant kinematic support suggests any storms that develop will be largely driven by cold pool dynamics. Damaging winds appear to be the main threat, followed by the potential of an isolated tornado, especially invof the warm front. Again, this is if convection initiates in the first place. Confidence is low for initiation, but high in severe potential if convection materializes. As upper ridging begins building in later in the period, subsidence will increase and precip chances will virtually disappear save for far northwestern AR. Expect a warming trend through the end of the period, with highs back in the low-to-mid 90s by Monday afternoon. Lows will range from the low-to-mid 70s each night. Cooper LONG TERM...Monday Night Through Saturday Models all in decent enough agreement that one model is not really favored versus another. Models all agree in the general synoptic pattern with the usual timing and strength differences that always show up as the period progresses. Bottom line is all models are showing a return to very warm and dry conditions across the CWA. Period initiates with upper trough/upper low moving through the central plains and broad ridging over the southeast CONUS. Strong thunderstorms will be possible with this upper low Tuesday but it looks like most will stay to the north of the state although a few of them dropping onto far northern Arkansas can not be discounted. Even after this upper system passes through, models continuously generate convection Wednesday which again could skirt the northern most counties. Come Thursday and beyond, models all agree that upper level ridging will build over the region. This will basically cut off any chance of precipitation although a diurnally driven storm can never be ruled out in this environment. High temperatures will soar into the 90s and its possible a couple of locations could see 100 degrees. Heat related headlines may be needed as the week progresses. Goudsward && .LZK Watches/Warnings/Advisories...NONE. && $$ Aviation...99
Area Forecast Discussion
National Weather Service Memphis TN
639 PM CDT Sat Jun 23 2018 .UPDATE... Updated to include 00z aviation discussion. && .PREV DISCUSSION... /issued 301 PM CDT Sat Jun 23 2018/ DISCUSSION... Most of the region recovering from morning convection with cu fields on satellite across the north and far south where the area was untouched from precipitation. Temperatures still cool along the Tennessee River with readings around 80F...hotter in the west with near 90F temperatures in the southwest Delta. Winds were breezy from the south in the wake of the morning storms as well. Tricky next 24 hours with regards to convection timing. Latest HRRR showing a few storms popping up early this evening over north Mississippi that may train through the night with little to no activity farther north until tomorrow. However...models from yesterday and Thursday were in strong agreement of organized convection sliding across the northern counties in the 06-12z time frame. So have split the difference with 40-50 pops across much of the region tonight. Temperatures tomorrow will be near average. Storms may still be lingering across the north tomorrow night where the midlevel westerlies remain strongest. Monday through shortwave to drop into the Plains and evolve into an upper low is anticipated this period. The GFS shows the entire Midsouth remaining in an active convective swath...while the NAM and Euro focus storms in the north and east with the southwest starting to heat up. Have leaned more with this NAM and Euro consistency. Temperatures will range from 89F to the northeast to 95F in the southwest...with triple digit heat indices building in. Heat advisories are possible for portions of the area. End of next week...both the GFS and Euro show the ridge building even further over the Central States. Widespread mid 90`s will be the rule with a few upper 90`s possible in the west. Heat indices in the 103F-109F heat advisories will be likely. JAB && .AVIATION... 00z TAF Cycle VFR conditions are ongoing as all terminals have remained free of any thunderstorm activity this afternoon and evening. A few storms present near KTUP currently, so have kept VCTS prevailing until midnight. Otherwise, models still hinting at a low stratus deck developing overnight, bringing MVFR or lower ceilings to the terminals. Also feel fog formation will be likely to reduce visibility at KMKL and KTUP during the overnight and early morning hours. Another MCS will likely impact the region by late Sunday morning, from west to east. Have handled this with VCTS currently, as timing and exact coverage are near impossible to resolve, thus extremely low confidence at this time. Regardless, VFR conditions will return by late in the period. Winds will be from the SSW throughout the majority of the period, generally less than 11 knots. ZDM && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
754 PM CDT Sat Jun 23 2018 .UPDATE... Issued at 722 PM CDT Sat Jun 23 2018 Updated to include 00z aviation discussion below. && .SHORT TERM...(This evening through Sunday) Issued at 239 PM CDT Sat Jun 23 2018 RAP h85 analysis has been depicting a pool of slightly higher theta-e air across central MN, which is where we have seen some isolated showers develop. The HRRR has has been showing this activity much of the day and that combined with RAP h85 theta-e forecasts supports this isolated activity continuing into the evening, so have some low pops across central MN through 6z to account for that. Satellite and radar imagery both easily depict a shortwave over central SoDak this afternoon. This feature will slide into western MN and slowly shear out across southern MN Sunday. Precip has been slow to develop to the east of this feature, so have really slowed down the progression of PoPs into southwest MN tonight. Tied arrival of chance pops on the movement a weak h5 vorticity max the RAP brings out of SoDak and into western MN. The NMM, though slow, probably is the CAM that is closest to what we are currently thinking for precip evolution tonight. Sunday, dewpoints will be a tick higher, with forecasting soundings from the NAM/GFS showing 1000-1500 j/kg of largely uncapped CAPE developing. Forcing wise, there is not much there, so this looks to result in unorganized scattered convection. Like today, Sunday will feature little shear and little in the way of a severe threat. But, slow storm motion will result in some very localized heavier precip amounts. .LONG TERM...(Sunday night through Saturday) Issued at 239 PM CDT Sat Jun 23 2018 The remainder of the week will see some progression of the large scale upper air pattern during the first half of the week before it gets bottled up toward the end of the period. The medium range guidance is in fairly good agreement on the overall evolution of the longwave features through the end of the week, with a bit more disagreement by the end of next weekend. The somewhat split flow currently over the central CONUS will become more phased by midweek after we see a shortwave trough move through our area on Tuesday and another passes by to our north Wednesday into early Thursday. After that the western side of a very broad sub-tropic ridge over the eastern US and western Atlantic will get pumped up over the central US with troughing over the western US. This will put us into what looks to be a potentially very busy period of weather from late in the week into the first part of the July 4th week. We should wind up hot and humid and will have forcing in place just to our west in association with the upper trough. So, could easily see a period of periodic MCSs moving through the region as the surface frontal boundary and cooler/drier air struggles to push east into the stubborn upper ridge. We`ll have a good chance for some showers/thunderstorms across the west Sunday night into early Monday, then eastward across the remainder of the area Monday night through Tuesday as the aforementioned southern stream shortwave trough moves through the region and surface low moves northeast from the central Plains across southern Minnesota. Widespread severe weather doesn`t appear likely, but there may be enough instability and shear for a few severe storms later Monday into Tuesday, particularly over the southern and southeastern portion of the area. We should see a break in precipitation chances Tuesday night and Wednesday as a weak surface ridge builds into the area. The northern stream shortwave trough moving by to our north later Wednesday and Wednesday night could produce some precipitation in the northern portion of the area, but most areas look to stay dry. After that, we look to have recurring chances for showers/thunderstorms with MCS passages from Thursday night through the remainder of the forecast period as activity develops to our west and moves east around the periphery of the upper ridge. At this point, it`s tough to pin point too much for completely dry periods, but better than one might expect at days 5-7 given better than typical agreement in the guidance. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 722 PM CDT Sat Jun 23 2018 VFR conditions expected through Sunday morning with increasing chances of showers and thunderstorms to follow going into Sunday afternoon. A few isolated showers are possible in western MN this evening but activity will become more organized overnight in far SW MN then gradually spread east through central-southern MN during the day and into western WI by the evening. Difficult to run with anything other than VCSH at this point, since chances are still around 30-40% and thunder chances are even less. So confidence is fairly high of seeing showers/thunderstorms across the region tomorrow but low confidence on exact timing/placement of storms at this point. Low chances for fog overnight due to high overcast expected across the area. KMSP...Precip looks to hold off until at least midday, allowing for more peak heating to tap into a moist/unstable atmosphere which will spark showers/t-storms. Conditions may briefly drop into MVFR/IFR should storms directly impact the terminal but VFR will be most prevalent. /OUTLOOK FOR KMSP/ Tue...MVFR possible. -SHRA/-TSRA likely. Wind SE bcmg NW 5-10 kts. Wed...VFR. Winds NW 5-10 kts. Thu...VFR. Winds SE 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ UPDATE...JPC SHORT TERM... LONG TERM...MPG AVIATION...JPC
Area Forecast Discussion
National Weather Service Blacksburg VA
946 PM EDT Sat Jun 23 2018 .SYNOPSIS... Low pressure aloft over the Ohio Valley will lift northeast tonight through Monday. High pressure aloft will build over the eastern U.S. during the later half of the week. Much of the upcoming week will feature warm and humid conditions with just isolated to scattered mainly afternoon and evening showers and thunderstorms. && .NEAR TERM /THROUGH SUNDAY/... As of 945 PM EDT Saturday... No major updates with this forecast adjustment. Have only tweaked hourly temperatures and dew points to reflect the latest conditions and expected trends through midnight. Also, made minor adjustments to the sky cover to reflect even less coverage prior to the arrival of the activity currently making gradual progress eastward through far southwest Virginia. As of 645 PM EDT Saturday... Very little remains in the way of showers across the region. This trend should continue as we approach sunset and the loss of the daytime heating. Additional showers will be possible later this evening as a disturbance moves into eastern Tennessee. The western quarter of the region may see isolated to scattered showers after midnight through daybreak Sunday. As of 300 PM EDT Saturday... Water-vapor imagery shows a mid-level trough over the Ohio Valley rotating eastward towards the Mid-Atlantic region this afternoon into tonight. The upper low will lift out across the northeast U.S. by Monday. SPC Mesoscale analysis at 18z showed that CAPEs have rebounded top 1k to 2k J/Kg east of the Blue Ridge. Lis this afternoon vary from minus one to minus three across eastern half of our Forecast area. The HRRR and HiResW-ARW-east showed scattered showers and thunderstorms developing this afternoon and moving east across our region into tonight. The latest day one convective outlook keeps a marginal threat of severe weather across eastern portions of forecast area. There is a small window for an isolated pulse severe thunderstorm in the east. However, the best instability will be pooled across the coastal plain to our south and east. With the loss of solar heating this evening expected scattered convection to diminish and tapper off into tonight. Once again expect areas of low clouds and fog to form overnight into Sunday morning. Low temperatures tonight will range from around 60 degrees in the mountains to around 70 degrees in the piedmont. Quasi-zonal mid-level height regime will govern conditions aloft across the East. Airmass should become moderately unstable which should lead to the development of scattered showers and thunderstorms Sunday afternoon. A couple of weak shortwave rotating across our area should enhance thunderstorms formation. SPC does have the far western portion of the CWA in a 5%/Marginal Risk of severe weather on day two convective outlook, which seems reasonable. High temperatures on Sunday will vary from the lower 70s in the northwest mountains to the lower 90s in the piedmont. /Confidence Levels/ Temperatures...High Precipitation Chances... medium Winds...Medium && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... As of 200 PM EDT Saturday... Sunday afternoon and evening thunderstorms will gradually fade away overnight as a weak front tracks across the region Sunday night into Monday. Stable air behind the front will keep thunderstorms chances low Monday, while temperatures will again warm above normal. Temperatures Monday will range from the low to mid 80s west of the Blue Ridge to near 90 east. North to northeasterly flow Monday night into Tuesday will bring a brief break from the heat as a wedge of high pressure skirts over the Mid Atlantic states and south-central Appalachains. Temperatures will range from the mid 70s to lower 80s west and low to mid 80s east. The wedge will slowly erode over the mountains during the day Tuesday as a cold front approaches from the west. Areas outside of the wedge may see a few thunderstorms develop in the afternoon, then fade during the evening hours. Areas that typically erode outside of the wedge first are the Mountain Empire of southwest Virginia west to the Bluefield-Richlands area. Greenbrier Valley may also come out of the wedge late Tuesday, depending on if the front is still over the Midwest or in the Ohio Valley. As the front continues to approach the area Tuesday night, the wedge will erode over the mountains, but remain entrenched across the foothills and piedmont counties into Wednesday morning. /Confidence Levels/ Temperatures - High Precipitation Chances - Medium Thunderstorm Chances - High && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 220 PM EDT Saturday... The GFS is quick to remove the wedge Wednesday morning, while the ECM hangs on to it over the piedmont into the early afternoon. In either case, scattered showers and thunderstorms will form over the area as the wedge erodes, it is just a timing issue. As the front tracks over the region Wednesday, more numerous showers and thunderstorms will over take the area. The front stalls over the piedmont overnight which may keep lingering showers in the area into the early morning hours Thursday. The front is expected to move east during the day Thursday with only an isolated chance for afternoon thunderstorms in the afternoon. Temperatures Wednesday and Thursday will run close to normal levels. A heat dome of high pressure over the southern Plains early in the week will move over the East Coast next weekend. Temperatures will once again run warmer than normal, ranging from the mid 80s to lower 90s across the mountains and mid to upper 90s east. Scattered thunderstorms are also expected to develop each afternoon and evening. /Confidence Levels/ Temperatures - Medium to High Precipitation Chances - Low to Medium Thunderstorm Chances - Low to Medium && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... As of 730 PM EDT Saturday... Isolated showers across the region are rapidly decreasing in coverage and should continue to do so through sunset with the loss of daytime heating. Additional showers are expected across mainly the far western parts of the region after midnight as a disturbances head east through Tennessee. Few ceilings exist across the area, and those that are around are in the VFR range. Ceilings will increase in coverage tonight, again with most being VFR. Far western parts of the region may see areas of MVFR ceilings. Patchy IFR/MVFR fog is possible late tonight into early Sunday morning in the mountain and river valleys. During Sunday, look for showers and storms to increase across the entire region, especially in the afternoon, as low instability increases once again thanks to surface heating and an upper level disturbance will approach from the Ohio Valley. As of 142 PM EDT Saturday... VFR conditions prevail this afternoon with isolated MVFR convection and low clouds. The entire forecast area is in the warm sector as winds shift south-southwesterly. Broad upper low over the Ohio Valley will continue to lift northeast this afternoon into tonight with the best upper support from this low also shifting north and east. Weak disturbances tracking around the upper low in the northwest flow and the moist, warm, unstable airmass may trigger scattered showers and isolated thunderstorms. Most taf sites will see a thunderstorm this afternoon,. Any convection that passes across an airport is expected to remain moving, with a brief period of heavy rain producing IFR conditions. With no real change in airmass, expect MVFR/IFR ceilings and patchy fog to redevelop early Sunday morning across the region. Morning low clouds and fog should lift by late sunday morning return taf sites to VFR. Scattered MVFR showers and thunderstorms will develop Sunday afternoon with best chances in the west. /Confidence Levels/ Ceilings...Medium Visibilities...Medium Wind...Medium to High Thunderstorm Chances...Low to Medium .Extended Aviation Discussion... A cold front will finally sweep through the region by Sunday night with improving mostly VFR conditions Monday and Tuesday. Isolated to scattered MVFR showers and thunderstorms are possible by Wednesday. Scattered MVFR convection continues Thursday. && .EQUIPMENT... As of 338 PM EDT Saturday... The NOAA weather radio transmitter in Hinton, West Virginia that is WXM72 and broadcasting at a frequency of 162.425 MHz is off the air. Parts are on order to repair the transmitter, but there is no known time of restoration. We apologize for any inconvenience. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...KK NEAR TERM...DS/KK SHORT TERM...RCS LONG TERM...RCS AVIATION...DS/KK/NF EQUIPMENT...
Area Forecast Discussion
National Weather Service Springfield MO
655 PM CDT Sat Jun 23 2018 .SHORT TERM...(This evening through Sunday) Issued at 302 PM CDT Sat Jun 23 2018 Overnight MCS skirted the area to the southwest across Oklahoma and Arkansas. The main surface boundary now lays across southern Oklahoma into central and southern Arkansas. This boundary will slowly lift northward tonight and Additional storms may develop within the frontal zone over Oklahoma and Arkansas during the overnight period as the southerly low-level jet strengthens. Both the NAM and NAMNest shows this, but the HRRR does not. Elevated instability does increase overnight across far southern Missouri as well. Did keep lower end probabilities to account for this potential, but confidence not real high. Depending upon what happen overnight, convection may linger into Sunday morning across at least southern Missouri. Meanwhile, a mid level low drops into western Nebraska intersecting the westward extent of the warm front that will be lying across northeast Kansas and northern Missouri by late afternoon. The warm sector across Kansas will become quite unstable with MLCAPES exceeding 4000 j/kg. Strong to severe convection likely to fire and then progress eastward with time and continue into Sunday evening with severe threat possible expanding eastward into southeast Kansas and western Missouri late Sunday into Sunday evening. .LONG TERM...(Sunday Night through Saturday) Issued at 302 PM CDT Sat Jun 23 2018 The entire system moves eastward on Monday, with surface cold front setting up across eastern Kansas. Most unstable CAPES of 3000 j/kg develop ahead of the front by afternoon, with the strongest deep later shear closer to front over western into central and northern Missouri. Give instability and shear will likely see the potential for strong to severe storms by afternoon and into Monday evening. Temperatures also look to be on the warm side, with highs in the upper 80s to near 90. It looks somewhat quiet but warm for Tuesday, with convective focus north of the area. However, GFS showing the northern Missouri convection developing into a southward moving MCS Tuesday night into Wednesday morning. Mainly quiet but hot weather is then expected from later Wednesday all the way through Saturday. Upper ridge builds back across the area and this will push temperatures back into the low to mid 90s and heat indices back near 100 or slightly higher. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 654 PM CDT Sat Jun 23 2018 Pilots can expect VFR conditions to prevail at area terminals tonight and Sunday. However the development of scattered storms late tonight through Sunday will have to be monitored. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ SHORT TERM...Raberding LONG TERM...Raberding AVIATION...Foster