Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/18/19


Area Forecast Discussion
National Weather Service Charleston SC
847 PM EDT Tue Sep 17 2019 .SYNOPSIS... Hurricane Humberto will continue to move away from the coast through mid week. A cold front will advance through the area Wednesday, followed by high pressure into early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... Quick Update to add slight chance POPs to Allendale County and surrounding areas. Radar shows isolated thunderstorms approaching this area. The HRRR indicates they should persist for at least the next 2-3 hours. We may need to expand this areal coverage further, depending on the future radar trends. Otherwise, a cold front will move south and should make it toward the Altamaha River near daybreak as Hurricane Humberto well offshore continues to move farther away. Some showers are expected to develop as moisture, instability and convergence increase a bit. Can`t rule out some weak storms but any thunder should mainly be confined to around the GA coast where the greatest instability is expected. Temperatures should fall to around 70 north and west toward the Pee Dee/Midlands with lower to mid 70s south and east toward the coast and GA Coastal Empire. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... Wednesday: Models in good agreement that the backdoor front will move through the area from north to south during the day. Models show some increase in moisture associated with the front and this is supported by cloud cover across Virginia at the present time. Some minor instability is expected to develop mainly in the afternoon across southeast Georgia. Threat for precipitation is low enough in the north due to the early arrival of the front that it was left out of the forecast. Highest rain chances will be in the south. Threat for precipitation will end by late afternoon. Made some minor adjustment to lower high temperatures from the Allendale/Walterboro areas south to near Savannah. Maintained highs in the mid to upper 80s southwest of this area, but have some concern that cloud cover may be sufficient enough to keep the high temperatures from getting that high. Highs will mainly be in the lower 80s in the north and along southeast South Carolina Coast. Drier air will move in behind the front with lows Wednesday night ranging from near 60 in the north to near 70 along the southeast Georgia Coast. Thursday: Drier air will continue to overspread the area in the wake of the cold front. The only exception will be along the southeast Georgia Coast near the Altamaha River where a few very light marine showers could brush the coast. Brisk northeast winds are expected along the coast. High temperatures area wide will be rather mild and this combined dew point temperatures in the 50s inland to the lower to mid 60s at the coast will make for a rather pleasant day. Highs should range from the upper 70s near the South Santee River to the mid 80s across far inland portions of southeast Georgia. A few light marine showers are possible in southeast Georgia mainly east of I-95 Thursday night. Friday: As surface high pressure begins to build from the Mid- Atlantic states into the western Atlantic, surface winds will become more onshore especially from Beaufort County south and this will allow the threat for some light marine showers to spread further inland especially across southeast Georgia. Highs should range from near 80 along the coast to the mid 80s far inland where more sunshine is expected and there is basically no threat for precipitation. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Deep layered ridging will persist over the weekend and then tend to break down during the first part of next week. Models continue to show dry weather prevailing through the entire period. High temps are expected to warm slightly above climo during the period, however overnight temps should continue to fall into the 60s each night away from the ocean as the atmosphere remains quite dry. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... 00Z TAFs: A cold front will move through the terminals late tonight into Wednesday morning. KCHS: Models indicate mainly dry conditions as the front passes. Hence, we have VFR prevailing. Though, winds could become gusty behind the front Wednesday afternoon. KSAV: Models show isolated to scattered showers developing ahead of the front. Since their is some uncertainty with the timing of these showers and their coverage/intensity, we opted to cover this with a PROB30 group and hint at borderline VFR/MVFR ceilings. Models even show hints of MVFR ceilings into Wednesday afternoon, but we`re keeping it barely VFR for now. Additionally, gusty winds could develop behind the front Wednesday afternoon. Extended Aviation Outlook: VFR conditions will prevail. && .MARINE... Tonight: A cold front will move south through most, if not all, of the waters with winds picking up from the northeast behind it. Seas will also build as a result and Small Craft Advisories are in effect for all waters except Charleston Harbor and the nearshore GA waters. Wednesday through Sunday: Northeast winds will dominate throughout the week in the wake of the backdoor cold front that moves through the waters on Wednesday. The combination of increasing seas and winds will result in Small Craft Advisory conditions for all coastal waters into Friday evening for the nearshore waters and well into Saturday night for the offshore Georgia waters. Looks like the best threat for Small craft Advisory conditions to occur in Charleston Harbor will be on Thursday. Later shifts will need to further evaluate and if necessary issue an advisory there. Rip Currents: Moderate Risk through Wednesday due to lingering elevated long period swells and increasing longshore currents due to strengthening northeast winds. The rip current risk will remain elevated through the end of the week as northeast winds and strong longshore currents continue. && .TIDES/COASTAL FLOODING... Low chances for minor coastal flooding around the times of high tide through late week, especially along the South Carolina coast. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...Small Craft Advisory from 2 AM Wednesday to 8 PM EDT Friday for AMZ352. Small Craft Advisory until 4 AM EDT Sunday for AMZ374. Small Craft Advisory until 8 PM EDT Friday for AMZ350. Small Craft Advisory from 11 AM Wednesday to 8 PM EDT Friday for AMZ354. && $$ NEAR TERM... SHORT TERM...MTE LONG TERM... AVIATION...MTE/RAD MARINE...MTE/RJB TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Dodge City KS
716 PM CDT Tue Sep 17 2019 ...Updated Aviation Section... .SHORT TERM...(This afternoon through Wednesday night) Issued at 1130 AM CDT Tue Sep 17 2019 Strong S/SW winds will impact SW KS through this afternoon, with gusts to the 40-45 mph range. A strong shortwave was over western Wyoming at midday, complete with morning forced convection in southern Wyoming via the lightning detection network. This system is dynamically impressive and will rotate in a negatively tilted fashion into western South Dakota this evening. This will all enhance pressure gradients through this evening, with MOS guidance now up to 29 mph sustained for several hours. Gusts to near 45 mph are expected through sunset, with more persistent, well above normal temperatures in the lower to mid 90s. 12z NAM, the latest HRRR iterations and a few other CAMs suggest isolated thunderstorm development is possible along/west of US 83 this evening. Included 20% pops for this potential, but coverage will be sparse, and wouldn`t be surprised if nothing develops at all. That said, a hot well-mixed windy boundary layer will support downburst potential from any high-based storms that develop. Another unseasonably warm night tonight, with sunrise temperatures in the 60s west, to lower 70s east. South winds will remain elevated at 15-25 mph well into the night, courtesy of another low level jet. A break from the Kansas wind machine is expected Wednesday. The shortwave to our north will be out of the picture, but more importantly, a weak surface trough of low pressure will bisect SW KS as a weak surface high pressure ridge noses into Nebraska and NW KS. This setup will reduce the winds substantially, still south at 15-25 mph south of the trough, but probably going light and variable (at times NEly) near and north of the boundary. Winds will likely be the lightest across the western/NW zones. Model consensus places the boundary near a Wakeeney-Garden City-Liberal line at midday. Given convergence along the boundary, long range HRRR and 12z NAM hint at isolated thunderstorm development. Again, coverage will be sparse, but will necessitate at least minimal pops. Another hot afternoon in the mid 90s will both encourage updrafts and downbursts from any high convective cloud bases. .LONG TERM...(Thursday through Tuesday) Issued at 210 PM CDT Tue Sep 17 2019 ...Severe Thunderstorms Possible Friday... Shower and thunderstorm activity will clearly return to SW KS Thursday and Friday, as a western US trough energizes SW flow aloft, interacting with a lee trough/dryline. The trough will be centered on the Great Basin late Thursday, with 12z GFS continuing to suggest convective initiation across the western zones Thursday afternoon/evening. The trough will be progressive, with models swinging the trough axis through the northern Rockies/plains by late Friday. Friday afternoon/evening in particular displays severe weather potential, with 12z ECMWF depicting a sharp dryline and surface low along the CO/KS border, and backed SEly surface flow. As always, mesoscale details will dictate hazards, their magnitude, and location, but early indications are some supercells are probable from portions of western Kansas through the Texas panhandle at peak heating Friday. Impressive shear and CAPE are apparent, and the strong tornado parameter from 12z ECMWF is eye opening, focusing across the western zones. Jet stream dynamics will be impressive south of the ejecting trough. Feel severe probabilities and NBM pops will increase with time. Both high and low temperatures will remain well above normal Thursday and Friday, with elevated south winds and moisture advection. Eventually, a weak cold frontal boundary will sag southward through SW KS over the weekend, probably assisted by thunderstorm complex outflows. 12z ECMWF depicts MCS development on this boundary across central Kansas late Saturday, with probable impacts for our eastern zones. NBM pops favor the eastern zones late Saturday which is the correct trend. Frontal forcing and convective potential is expected to move SE of SW KS by Sunday, and with broad ridging rebounding, a dry forecast will return by then. Temperatures by Sunday will be closer to normal for September, with lows from 55-65 and highs from 80-85. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 712 PM CDT Tue Sep 17 2019 Fairly quiet weather will prevail through this TAF period with widespread VFR flight category continuing. A rogue shower/thunderstorm was in vicinity of the LBL terminal at the onset of this TAF period, but otherwise dry weather will remain in place. South winds will continue through the night with a fairly strong low level jet developing after sunset leading to some marginal LLWS conditions not far off the surface. A surface trough axis will advance slowly east across western Kansas on Wednesday, and this will lead to weakening wind, especially LBL and GCK which will be closest to this trough axis (if not right in vicinity of this trough axis). There is still some question as to how far east this trough axis will reach by afternoon, so there are some uncertainties in the wind forecast in the last 6-9 hours of this TAF period. && .PRELIMINARY POINT TEMPS/POPS... DDC 69 96 68 90 / 0 20 0 20 GCK 65 95 65 91 / 20 0 10 30 EHA 62 91 64 89 / 20 0 10 30 LBL 66 95 67 89 / 20 0 10 30 HYS 69 93 68 90 / 10 20 10 20 P28 70 95 69 89 / 0 10 10 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Turner LONG TERM...Turner AVIATION...Umscheid
Area Forecast Discussion
National Weather Service Grand Forks ND
1041 PM CDT Tue Sep 17 2019 .UPDATE... Issued at 947 PM CDT Tue Sep 17 2019 Adjusted PoPs to reflect recent HRRR runs that suggest weak convection ongoing along a pre-frontal trough across central SD will intensify as it moves into northeast SD and interacts with a less stable environment. Recent radar and lightning trends suggest this convection has been slowly intensifying, so the recent HRRR runs seem reasonable. Will continue to monitor for the potential for severe weather through the night across far southeast ND and west central MN. && .SHORT TERM...(This evening through Wednesday) Issued at 343 PM CDT Tue Sep 17 2019 For tonight, a similar setup to yesterday is expected with a cold front moving east across North Dakota. Expect to see gusty southerly winds decrease this evening with temperatures remaining mild due to increased cloud cover. Canadian and GFS guidance both suggest the possibility of light rain showers west of Devils Lake due to a weak 500mb shortwave. Tonight, a broad 850mb jet out of the south will be providing warm air advection, strongest across Minnesota. The jet will be similar to yesterday and possibly stronger to near 60 knots in some areas. There has been disagreement for the placement and timing for convection, but the trend has been pushing initiation later than midnight and further to the east than previously expected. Fergus Falls and Park Rapids have the best chances after midnight and before sunrise. The showers and storms will push northward during the morning. With the southern end of the upper-level trough lingering throughout the day near the international border, some rain showers may be possible in that area during the afternoon. Winds will become westerly and very gusty at times with 30mph gusts possible along and west of the Red River Valley. Highs will be slightly cooler in the 70s area-wide. .LONG TERM...(Wednesday night through Tuesday) Issued at 343 PM CDT Tue Sep 17 2019 With winds and cloud cover expected to subside behind the front, temperatures will be cooler but still above normal for Wednesday night. Lows will be in the 50s with stable air keeping the area dry. 12Z Thu - 00Z Sat Low level moisture returns to the Red River Valley late Thu night into Fri. Precipitable water rises Thu night and Fri to around 1.5 inches. Models soundings show instability increases Thu night as well as the cap. Cap dissolves by Fri afternoon. Also Cape throttles back as mid level temps increase. Shear is stronger in the western Dakotas Fri and shifts over the forecast area on Sat. Sat - Tue Long wave trough over the western US will shift to eastern North America by the end of the period. Low amplitude long wave ridge over the eastern Pacific shifts. The GFS becomes the faster solution compared to the ECMWF on Sat. But by Sun the models phase back up. Upper low off the Pacific Northwest coast will move across the region Sat. Main frontal boundary to move through Sat and majority of precip will shift into Canada by later Sat. European and GFS ensembles give best precip for Fri and Sat. Heavy rain will also be possible. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1040 PM CDT Tue Sep 17 2019 VFR conditions are expected to continue overnight tonight for most locations. The exception is KBJI where scattered showers and thunderstorms are expected as a cold front pushes through the region. As this occurs, MVFR, and possibly period of IFR, conditions are likely. The main impact for aviation in the TAF period will be the winds. Southerly winds sustained at 10-15 knots will diminish slightly overnight before shifting to the west and picking back up Wednesday morning. One exception to this is KFAR which has continued to see gusts into the 20-30 knot range well after sunset. Given that this location saw persistent overnight gusts last night under a similar weather regime, wind gusts into the 20-25 knot range overnight can`t be ruled out. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...AM SHORT TERM...Godon/Wasilewski LONG TERM...Godon/JH/Wasilewski AVIATION...AM
Area Forecast Discussion
National Weather Service Hastings NE
614 PM CDT Tue Sep 17 2019 ...AVIATION UPDATE... .SHORT TERM...(This evening through Wednesday Night) Issued at 308 PM CDT Tue Sep 17 2019 The gusty south winds will continue through this afternoon, but will gradually taper off this evening as low level mixing decreases. Winds will then back off even more as a cold front moves in from the northwest after midnight. There is still a chance that a few showers or thunderstorms could develop as an increasing LLJ intersects this front, but the latest runs of the HRRR have been pretty unimpressive. This front then stalls in the area tomorrow, which creates some uncertainty on high temperatures for tomorrow. The current forecast has a range from 80 near Ord to the low 90s in northern Kansas, but I wouldn`t be surprised if we see an even larger spread in temperatures across the area. By late tomorrow afternoon, we could see a few isolated thunderstorms develop along the front. Then later overnight we may see more convection develop as a shortwave pushes in from the west. An isolated strong storm is possible through the evening and overnight, but deep layer shear is lacking and should inhibit an organized severe threat. .LONG TERM...(Thursday through Tuesday) Issued at 308 PM CDT Tue Sep 17 2019 Models have begun to show more thunderstorms lingering into Thursday morning, especially for areas east of Highway 281. After this activity clears, I believe that we will remain mostly dry through the rest of the daytime as we move back into southeasterly flow at the surface and we see rising heights aloft. A bit better chance for thunderstorms then returns late Thursday night into Friday as a deeper trough crosses the Rockies and slowly moves into the central Plains. Friday will likely be another breezy day as the trough approaches. The highest PoPs then arrive Friday night into Saturday as the base of this trough ejects out of Colorado. As this trough departs, we will see more seasonable and pleasant weather Sunday and Monday. Mostly dry conditions are expected, and highs are forecast to be in the mid 70s to low 80s. Confidence then decreases as models diverge on the upper level pattern early next week. The GFS and Euro are now both producing a cutoff low over the western CONUS, but timing and location vary considerably. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday) Issued at 608 PM CDT Tue Sep 17 2019 SFC winds will taper off this evening a 45-50kts LLJ will setup causing some LLWS at the TAF sites tonight. A cold front moving through the region tomorrow will cause some challenging wind FCST. Some models keep the winds out of the south and others bring it out of the north. Have elected to keep a northerly wind in the TAFS at this time, some cooler weather would be nice. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Mangels LONG TERM...Mangels AVIATION...Beda
Area Forecast Discussion
National Weather Service Springfield MO
638 PM CDT Tue Sep 17 2019 .SHORT TERM...(This afternoon through Wednesday) Issued at 1231 PM CDT Tue Sep 17 2019 We are pretty much on track with temperatures this afternoon with most locations already in the lower to mid 90s. A few patches of cumulus were building over the area with the thicker patches between Rolla and Ft. Wood and near Table Rock Lake. Much thicker cumulus was developing east of our forecast area over southeast MO and western KY/TN. The latest HRRR has been trending even more isolated with afternoon storm coverage. Will monitor cloud trends southwest of Springfield for isolated storm development also, with any activity diminishing after sunset. There will not be much change in overall weather pattern for the next 24 hours, so will continue with hot afternoon conditions and isolated afternoon storms. Expect to see a slight uptick in coverage compared to today as moisture from the northern Gulf tropical depression shifts northward. .LONG TERM...(Wednesday Night through Tuesday) Issued at 255 PM CDT Tue Sep 17 2019 The upper ridge currently over the region will build further to the east as moisture increases ahead of a deepening trough over the western US. With added moisture from the remnants of Imelda we could see a little more coverage in afternoon storms over our southwest counties, and overall temperatures a few degrees lower than Wednesday, but still above normal. Will continue to keep the increasing precipitation chances from Friday through the weekend as the upper trough shifts eastward into the upper Midwest and places our region in southwest flow aloft. Several disturbances will interact with a surface front and moisture from the tropical storm remnants. Have some concerns that flooding from training storms will become more likely later in the weekend if the surface front lines up parallel to the upper flow. Have included flooding potential in the Hazardous Weather Outlook for late Saturday and Sunday. A weak shortwave ridge is forecast to build back into the region on Monday and Tuesday. However will hang on to some low precip chances as the GFS keeps a front stalled over the region. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 636 PM CDT Tue Sep 17 2019 With an upper level ridge over the region, VFR conditions are expected through the next 24 hours. Winds will remain light from the south as a lee side trough gradually deepens over the eastern Rockies. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ SHORT TERM...Terry LONG TERM...Terry AVIATION...Titus