Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/08/19

Area Forecast Discussion
National Weather Service Bismarck ND
1004 PM CDT Fri Jun 7 2019 .UPDATE... Issued at 1000 PM CDT Fri Jun 7 2019 Main change for this update was decrease the severe thunderstorm threat north and west of the current watch area. Near term models continue to suggest convection currently across northern South Dakota will rise north and east tonight. The latest iteration of the HRRR still has a few updraft helicity tracks moving into central North Dakota suggesting there is still some severe weather potential within the multicellular clusters. UPDATE Issued at 659 PM CDT Fri Jun 7 2019 So far the convection over central ND is having a hard time getting started. The northern portion of the line is looking more favorable for organized convection. CAMS are still indicating convection here, but with limited shear and as we pass peak heating, the threat for severe weather may be limited to the Devils Lake Basin and north and east. For the southwest and south central, we are still monitoring the potential for severe weather later this evening. This has also trended later, but the threat remains. Will continue to monitor. Made just some minor changes at this time to pops and sky cover. We did let the wind advisory expire. && .SHORT TERM...(This evening through Saturday) Issued at 341 PM CDT Fri Jun 7 2019 This afternoon, an amplified midlevel trough was moving over the northern Rockies with an associated surface low over southern Saskatchewan/Manitoba. At the surface a relative cold front/surface trough axis was placed through central North Dakota. Ahead of the frontal boundary, ample daytime heating and surface dew points around 60 F have lead to a conditionally unstable warm sector. Given continued destabilization this afternoon, convective initiation is expected along the boundary...particularly favoring the nose of a 850mb thermal ridge from near Towner/Cavalier counties south/southwest into Burleigh/Kidder counties. Though midlevel winds are marginal with effective bulk shear values around 25-30 kts, ample MLCAPE values of 2000-3000 J/kg will be enough for isolated severe hail/wind threats along this front. Also this afternoon, convection has been developing off higher terrain in eastern Montana/Wyoming. This is forecast to make its way into southwest North Dakota by 00Z-02Z along the western side of the frontal zone. Deep layer shear values of 50+ kts and largely parallel to the frontal zone will favor storm modes of supercells initially and then a transition to upscale cold-pool driven growth. With much of the storm-scale and gust front interactions likely occurring just upstream or into southwest North Dakota, depicting a likely storm mode has been a challenge and will possibly not be revealed until its occurrence. If there are still forms of discrete supercells or even clusters, large hail and locally damaging wind gusts will be the main threats. But with ample opportunity for storm interactions with deep shear vectors oriented along the frontal boundary a transition to mostly a severe wind threat is likely as this convective activity marches through southwest into south-central North Dakota. On the high end of the spectrum of possibilities, if a narrow corridor of more northeasterly low level flow develops, enhancement of gust front convergence may be possible thus developing a more widespread severe wind threat (as highlighted by the Enhanced risk in the SPC Day 1 outlook). Through the day Saturday, the surface cold front slowly advances eastward with lingering instability the basis for scattered showers and thunderstorms. With the front advancing into eastern North Dakota by the afternoon hours, severe weather is not expected in the western and central post-frontal regime. Strong cold air advection will spread across the state, leading to high temperatures in the low 60s west to mid 70s in the James River Valley. .LONG TERM...(Saturday night through Friday) Issued at 341 PM CDT Fri Jun 7 2019 The upper level trough swings through the Northern Plains Saturday night bringing and end to the precipitation. A northwest flow pattern then sets up Sunday through mid-week, with periodic shower and thunderstorm chances. Temperatures will remain mainly in the mid 60s through mid 70s for highs and 40s to lower 50s for lows. We then see a possible warming trend as we approach the end of the work week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 659 PM CDT Fri Jun 7 2019 VFR conditions to begin the TAF period. Latest short term models continue to show thunderstorm development trying to get going over central ND, from east of Bismarck into the Devils lake Basin. Later this evening, the potential for another round of convection is expected to spread southwest to northeast across the forecast area. Here we utilized a blend of guidance for our best guess for timing. The timing has also slowed from earlier today. We did include a bit higher of a wind gust potential for KDIK and KBIS with the convection as these sites appear to be favored for the potential for stronger winds, over remaining sites. Expect additional updates for timing as we go through the afternoon/evening. All TAF sites will have the potential for MVFR to IFR cigs/vsbys in thunderstorm activity with erratic thunderstorms winds. Northwest flow eventually sets up across the area late tonight through Saturday morning. MVFR ceilings are also possible Saturday behind the cold front. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CK SHORT TERM...AE LONG TERM...TWH AVIATION...TWH
National Weather Service Jackson KY
1114 PM EDT Fri Jun 7 2019 .UPDATE... Issued at 1114 PM EDT FRI JUN 7 2019 Showers have continued to diminish throughout the evening, with the exception of the area of storms just south of our CWA border. These have finally began propagating northward into our southern counties, but they seem to be much weaker and more progressive. A few other pop up showers are starting to show up across the SW CWA as well. The latest HRRR has a good handle on the current conditions, so tried to trend pops over the next few hours towards it. This keeps likely pops in the SW CWA through about 6Z, then tapers off to chance for the remainder of the night. Also with the lack of rain that was originally forecast, it is possible that the wet surface cooling could lead to fog development. Kept coverage patchy, but expanded the fog potential across more of the CWA to better handle this potential. Finally loaded in the latest observations to make sure the near term grids were on track with the current conditions. However, it was noted that the observations have not come in for the last few hours, so this something that will need to be addressed. All updates have been published and sent to NDFD/web. UPDATE Issued at 756 PM EDT FRI JUN 7 2019 Thankfully, showers have really dwindled over the last couple of hours, with most of the CWA now seeing drier conditions. A complex of storms remains nearly stationary just south of our CWA border in NE Tennessee, so as time goes on it seems as though the threat of this complex moving into our CWA is also beginning to dwindle, with the exception of a few light showers. Reworked the pop and weather grids through the evening and into the overnight based on the current radar trends, as well as the latest CAM data. In addition, made sure the near term forecasts for temps, dew points and winds were on track with the current observations. All updates have been published and sent to NDFD/web. && .SHORT TERM...(This evening through Saturday night) Issued at 445 PM EDT FRI JUN 7 2019 20z sfc analysis shows a broad area of low pressure south of Kentucky with a developing warm front pushing north into eastern parts of the state. On satellite, the colder cloud tops are found over the southwest parts of the JKL CWA. This is associated with a seemingly MCV spinning near our border with Tennessee. This area is also responsible for an swath of showers and building thunderstorms pivoting into the Bluegrass State this afternoon. This rain could exacerbate the flood potential - especially in western parts of the Cumberland Valley. The rain and persistent cloud cover had kept temperatures from climbing too far into the lower 70s for most places across the area this afternoon with dewpoints similar. Winds through the day have mainly been from the east to northeast at 5 to 10 mph. Some breaks in the clouds are now working into southeast Kentucky and this could help to build the instability leading to renewed convection and additional heavy rains into the evening. The models are in good agreement aloft through the short term portion of the forecast. They all depict a closed upper low drifting east into the Tennessee Valley and only slowly filling through Saturday night. Plenty of energy will circle this low during this time keeping the upper levels active through the period. Given this agreement have favored the NBM as the starting point for the grids with current radar trends and the CAMs leaned upon in the near term for PoP and QPF details. The specifics from the NAM12 were also catered to for Saturday and Saturday night. Sensible weather will feature a continued threat of heavy rainfall from redeveloping showers and thunderstorms. High precipitable water through the weekend will keep the threat around through the entire short term portion of the forecast. Do expect the rains to have a diurnal cycle to them favoring the afternoons and evenings, but tonight`s threat could linger past midnight given the maturity of the low level circulation in place with the MCV just to our southwest. Look for areas of fog tonight when it is not raining with additional showers and storms developing later in the day on Saturday. Similarly, the convection should die down Saturday night, but still be enough of a threat to maintain the flash flood watch through the entire period. Used the NBM guidance to start off the grids with some adjustments to hourly temperatures at max heating and also late at night per climatology. Did also make significant changes - mainly higher - to PoPs and QPF to better account for near term radar trends and the consensus of the CAMs. .LONG TERM...(Sunday through Friday) Issued at 510 PM EDT FRI JUN 7 2019 The models are in fairly decent agreement aloft through the extended portion of the forecast - especially considering that it should be a rather active pattern. They all depict the closed low detailed above being absorbed by a fairly vigorous trough cutting through the Central Plains Sunday night into Monday morning. This brings additional height falls to Kentucky to start the week, though the best energy will stay further north with the core of the trough moving into the Great Lakes that night. Through this trough`s passage the ECMWF is a notch stronger than the GFS and was favored. In the wake of the initial trough, heights will briefly rebound mid week before the next broad trough descends into the Plains, though this time the GFS is a bit better developed than the ECMWF. This trough continues to deepen as it approaches eastern Kentucky with the ECMWF overtaking the GFS by pouring its energy deeper into the region before swinging itself through the Ohio Valley and across Kentucky on Thursday. Slowly, heights will rebound for the area on Friday with the system departing to our northeast - though the GFS lingers it a bit longer than the ECMWF. Given the fair agreement for this situation have favored the blended solution with little need for large scale adjustments. Sensible weather will feature a wet end to the weekend and start to the new work week as the slow moving upper low pushes across the area. This prolonged rain event (and threat for additional flash flooding) ends as a cold front pushing through on Monday with drier air moving in - even clearing the sky from west to east that evening. Accordingly, the seasonably cool weather continues - but without the miserable high humidity. The dry spell of weather does not last long, though, as a developing area of low pressure to the south brings the threat of showers and thunderstorms back into the area by Wednesday afternoon. A passing cold front will renew our cool weather for Thursday along with additional chances for convection. Friday should be a dry and cool day in the wake of the late week front as high pressure parks over the area. Did adjust the NBM starting point temperatures a bit at night later in the week as the dewpoint depressions increase allowing for likely ridge to valley differences. As for PoPs, made less changes in the extended than the short term given the greater uncertainty and room for larger changes as the models come into better focus. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 808 PM EDT FRI JUN 7 2019 Latest radar trends show showers continuing to dwindle this evening, with this trend expected to persist into the overnight. While a few showers can`t be ruled out, widespread activity is not likely, therefore only included VCSH. With ample moisture in place, it is likely that fog will develop as we cool down overnight (outside of any ongoing rainfall). While the exact impacts and timing of fog are still in low confidence until it develops, still expect times of IFR or below throughout much of the night. Fog will quickly lift Sat morning, giving way to MVFR clouds and another day of rain/thunderstorm chances. Clouds are forecast to lift to VFR by the afternoon, but this will also be the best time frame for convection. Went predominate -SHRA and VCTS after 18Z to account for this. Winds will remain light and variable through the evening and overnight, but by tomorrow expect prevailing easterly winds, gusting to between 15 and 20 kts in the afternoon as well. && .JKL WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch through Sunday evening for KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...JMW SHORT TERM...GREIF LONG TERM...GREIF AVIATION...JMW
Area Forecast Discussion
National Weather Service Memphis TN
1017 PM CDT Fri Jun 7 2019 .UPDATE... Rain continues to fall across the region, most substantially this hour across North Mississippi. The latest HRRR guidance suggests much of this will come to an end over the next couple of hours. However, with the upper low situated over the region, believe showers will be possible areawide throughout the night. Did not completely remove POPs tonight for this reason, but did reduce them, especially across western areas. The Flash Flood Watch will end across the western areas at midnight, but will continue in the eastern counties through Saturday afternoon. With the upper low slow to move out of the area by the afternoon hours, still feel there`s a chance of POPs across eastern areas on Saturday. The rest of the forecast is on track at this time, with no further updates warranted. ZDM && .PREV DISCUSSION... /issued 641 PM CDT Fri Jun 7 2019/ UPDATE...Aviation Discussion. PREV DISCUSSION... /issued 253 PM CDT Fri Jun 7 2019/ Currently upper level low and weak surface low were rotating close to the Memphis metro...with moderate to heavy showers again not moving very fast across portions of eastern Arkansas and southwest Tennessee. Farther east ahead the system activity has been more transient...and in locations that are gladly accepting the rainfall. A flash flood watch has been issued to capture the training of cells. Current temperatures ranged from the low 70s to the low 80s. Winds were either calm or light and variable. For tonight and tomorrow...models showing a slower trek of the current upper level low this period with it becoming stalled in the Tennessee River Valley by early tomorrow. CAM`s show today`s activity once again waning quickly around sunset...but can`t rule out redevelopment somewhere in the CWA after midnight that could cause flooding. Later tomorrow it appears most of the heaviest activity and coverage will be across the eastern half of the CWA. Overall an additional 2-4 inches of rainfall is possible across portions of the flash flood watch area. Lows tonight will drop to near 70F with highs Saturday in the upper 70s to mid 80s. Sunday and Monday...a stronger west northwest flow aloft of 30-40kts will slowly invade the region...though models are showing the eastern counties still under deep enough moisture from the upper low for significant cloud cover and scattered convection coverage on Sunday. Elsewhere convection will become more isolated with more sun. By Monday a fast approaching shortwave will drop into the mid Mississippi Valley. This feature will be accompanied by a pronounced cold front that will bring a more April like change to the region. A few showers or storms may form along and behind the front coupled with breezy north winds...but it will be well worth the incoming changes with the new airmass. Highs both days will be in the low to mid 80s with lows Monday night falling into the low 60s. Tuesday through Thursday...except for a few stray showers from a passing disturbance late Wednesday in the north the period will be mostly dry. Temperature highs will fall to around ten degrees below normal...thats highs in the mid 70s to low 80s. More importantly models agree on dewpoints falling into the 50s area wide. Heat indices in the 90`s will be forgotten as AC`s can be turn off and windows cracked open...especially at night as lows fall to the mid and upper 50s. This cooler and drier trend may continue into early next weekend as an upper trough remains fixed over the Great Lakes and Ohio Valley. JAB && .AVIATION... 00Z TAF cycle Showers and thunderstorms should continue to diminish in both coverage and intensity over the next several hours. Additional showers may develop tomorrow morning, though coverage is questionable. Lows clouds should remain over much of the region for much of the forecast period. Some patchy areas of fog may develop overnight mainly over eastern sections of the forecast area. Winds, generally northerly may be through the forecast period, especially near showers/thunderstorms. && .MEG WATCHES/WARNINGS/ADVISORIES... AR...Flash Flood Watch until midnight CDT tonight for Clay-Craighead- Crittenden-Cross-Greene-Lee AR-Mississippi-Poinsett-St. Francis. MO...Flash Flood Watch until midnight CDT tonight for Dunklin- Pemiscot. MS...Flash Flood Watch until midnight CDT tonight for DeSoto-Tate- Tunica. Flash Flood Watch through Saturday evening for Alcorn-Benton MS- Chickasaw-Itawamba-Lafayette-Lee MS-Marshall-Monroe- Pontotoc-Prentiss-Tippah-Tishomingo-Union. TN...Flash Flood Watch until midnight CDT tonight for Dyer-Lake- Lauderdale-Obion-Shelby-Tipton. Flash Flood Watch through Saturday evening for Benton TN-Carroll- Chester-Crockett-Decatur-Fayette-Gibson-Hardeman-Hardin- Haywood-Henderson-Henry-Madison-McNairy-Weakley. && $$