Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/09/17

National Weather Service Jackson KY
1153 PM EDT Mon May 8 2017 .UPDATE... Issued at 1152 PM EDT MON MAY 8 2017 Based on latest radar trends with scattered showers moving into the CWA, made some tweeks to the pops to better cover the ongoing coverage. This resulted in some updates to the weather and QPF as well. Will continue to monitor radar and latest Hi-res models in case any more updates need to be made over the next few hours before the morning forecast package. All changes have been saved and sent to NDFD/web. UPDATE Issued at 1120 PM EDT MON MAY 8 2017 Did a quick update to fine tune the PoPs and Wx through the next few hours as a few showers have drifted into the area a bit ahead of schedule. Also, fine tuned the T and Td grids per the latest obs and trends. An updated ZFP will be issued shortly along with the grids sent to the NDFD and web servers. UPDATE Issued at 845 PM EDT MON MAY 8 2017 00z sfc analysis shows high pressure retreating from the area in the face of an approaching, and developing, warm front. Mid level clouds are sliding into the area ahead of this boundary. This should prevent the development of too large a ridge to valley difference and one that lasts through the night. However, there is a short window of time where a few of the eastern valleys could drop down into the low to mid 40s before rebounding after midnight as thicker and lower clouds move into the area. Have reflected this in the grids with this update. Currently, readings are in the upper 50s to lower 60s most places, though those eastern valleys are in the mid 50s. Meanwhile, dewpoints vary from the mid 40s west to the low and mid 30s east - helping to give those eastern cold spots room to drop through the rest of the evening. Winds have dropped off, too with most places just light and variable. Have also adjusted the arrival of the showers late tonight from southwest to northeast by dawn per the latest HRRR run. Kept the threat for thunderstorms in the forecast for well after midnight and into the morning hours of Tuesday. Finally, touched up the T and Td grids per the latest obs and trends. These updated grids have been sent to the NDFD and web servers. && .SHORT TERM...(This evening through Tuesday night) Issued at 314 PM EDT MON MAY 8 2017 At 2 PM surface high pressure was centered over central KY and a surface low was over southeast South Dakota. A warm front extended from the low southeast into far western KY. A blocky upper air pattern remained in place across North America with closed upper lows centered over southern Quebec and south of California with upper ridging in the plains. The warm front will move northeast across KY tonight and Tuesday before becoming stationary over northeast KY or WV. Showers are expected to break out ahead of the front tonight and a few thunderstorms will also be possible. Temperatures tonight are tricky, as very dry air remains in place ahead of the warm front, and temperatures would drop quickly in the sheltered valleys after sunset unless clouds move in quick enough. Clouds and scattered showers over IL and IN are moving southeast, and current forecast increases clouds fairly quickly this evening. We did lower temperatures a few degrees from the standard blend in the far eastern valleys since this will be last area to cloud up tonight. However did not go nearly as low as COOP MOS would indicate for colder spots. Coldest spots are generally in the mid 40s in the forecast for tonight, but COOP MOS points towards mid to upper 30s. Showers and a few thunderstorms will continue on Tuesday, mainly across the northeast part of the forecast area. On Tuesday a short wave trough will dive southeast into the mean long wave trough in the eastern U.S. and an associated surface low will move southeast along the front. This will focus shower and thunderstorms in the far northeast part of our area, with latest model guidance suggesting the heaviest rains with this will be north and east of east KY, at least for Tuesday. With the blocky pattern in place the front will remain quasi-stationary in or near our forecast area on into Tuesday night, but rain chances will temporarily diminish after the passage of the wave on Tuesday. .LONG TERM...(Wednesday through Monday) Issued at 314 PM EDT MON MAY 8 2017 A quasi-stationary frontal boundary will be located over the Tri- State area Wednesday morning and the boundary will stay very close to, if not over, northeast Kentucky through Thursday. Due to it`s location, PoPs will be highest over north and northeast Kentucky Wednesday through Thursday, but cannot rule out a shower or storm even down south along the Tennessee border. The front will also cause a sharp temperature gradient with highs Wednesday and Thursday ranging from the lower 70s over northeast Kentucky up to the upper 70s to low 80s over the Cumberland Valley region. The front will drop south slowly Thursday evening through Friday evening bringing our best chance for showers and storms areawide. Given the multiple rounds of storms expected, there remains a concern for flooding to develop and will continue to highlight that potential in the HWO. + self.daylight() Once the front drops to our south, a drier and cooler airmass will filter into the region over the weekend. Models have come into better agreement with the 12z runs bringing another cold front southward through the area on Sunday. The front is moisture starved and will not offer any PoPs with its passage right now. A reinforcing shot of cooler air will then follow this frontal passage keeping temperatures near or slightly below normal as we head toward the new week. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 830 PM EDT MON MAY 8 2017 Mid level clouds will increase this evening as a warm front approaches from the southwest. Ceilings will gradually lower overnight and showers will break out across the region as the warm front nears the area. A thunderstorm will also be possible late tonight and Tuesday morning, but whether a TAF site will be impacted is still uncertain. Thunder chances will begin in the southwest part of the area after 06Z and after 11Z in the northeast. Ceilings are expected to remain VFR in the southwest part of the forecast area, but lower to MVFR in the north and east by around 12Z. Showers will be most numerous Tuesday morning in the northeast part of the forecast area where IFR conditions may develop. Winds through the first part of the forecast will be light and variable with an increase from the southwest to west at 10 to 20 kts in the downstream portions of the Cumberland Valley later in the day, Tuesday, while lighter winds remain further northeast - away from any thunderstorms. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JMW SHORT TERM...SBH LONG TERM...ABE AVIATION...SBH/GREIF
Area Forecast Discussion
National Weather Service Louisville KY
1024 PM EDT Mon May 8 2017 .Forecast Update... Issued at 1024 PM EDT Mon May 8 2017 Did a quick update to back off PoPs in the western half of the forecast area overnight. Both the 00Z HRRR and NAM runs are a bit more east with the wave coming in tonight and suggest additional convection will develop a little more eastward out toward the I-75 corridor late tonight. Thus, have reduced PoPs over the I-65 corridor and points west. Minor adjustments were made to the T/Td/Wind grids to bring them up with current observations and the latest model trends for the overnight period. Updated forecast products and grids will be available shortly. && .Short Term (Now through Tuesday Night)... Issued at 259 PM EDT Mon May 8 2017 A few showers have crossed into the northwest corner of the LMK CWA ahead of a weak wave over the mid-Mississippi Valley. These showers will continue through the late afternoon and then wane this evening as the sun sets. Dew points have been surging northeast today in the Plains and Midwest on the south wide of a warm front developing from South Dakota to the Pennyrile. The front will drift to the northeast tonight and allow some of those higher dew points into the lower Ohio Valley. An upper wave traveling from the lower Great Lakes to the upper Ohio Valley will help to spark showers and thunderstorms along the warm front after midnight tonight. The best chances will be northeast of the surface boundary closest to the upper wave and in region of best isentropic lift. Tomorrow the wave will push off to the east and should take the bulk of the convection just off to our east as well, so while we`ll have showers and thunderstorms in the forecast it won`t be an all-day rain. The best chances for rain should be in the morning. There will be decent elevated instability with MUCAPE around a thousand near the front in the afternoon, but a sufficient trigger may be lacking and deep moisture will decrease from what we will have seen in the morning. Deep layer shear looks weak as well, and heights will be rising slightly. Wet bulb zero heights indicate that if storms do get going they could drop small hail. Temperatures Tuesday will vary a lot from one side of the front to the other. Southwestern areas will easily get into the 80s. The northern Blue Grass may get into the lower 70s, but if there`s enough cloud cover and rain then those areas won`t get out of the 60s. Winds will get a little gusty in the warm sector, probably to 20-25mph. Tuesday night the front will still be nearby with scattered convection along and northeast. While QPF isn`t very high right now, we`ll have to keep an eye on southern Indiana east of I-65 for any water issues if there are several episodes of training storms along the surface boundary. .Long Term (Wednesday through Monday)... Issued at 304 PM EDT Mon May 8 2017 Though we`ll have weak upper ridging Wednesday-Thursday, the surface warm front mentioned in the short term discussion will remain in or near the Ohio Valley during that time, keeping showers and thunderstorms in the forecast. By Friday the front may slide off to the southeast, but an upper shortwave trof will move overhead for a continued chance of scattered showers and storms. The weekend into Monday is a low confidence forecast for now, with either weak ridging or northwest flow aloft depending on how a Plains upper ridge develops. Individual ECMWF members and ensemble mean lean more toward a dry forecast than toward a wet one. GEFS also seems to lean dry, though not as strongly as the EC. MEX PoPs are well below normal, the inherited forecast is dry, and neighbors are dry. So, will continue with a forecast on the drier side for now. && .Aviation...(0Z TAF Update) Issued at 730 PM EDT Mon May 8 2017 The main TAF concerns are a chance for showers or an isld storm tonight and breezy winds tomorrow. A disturbance will dive southeast into the Ohio Valley tonight bringing showers and even an isld t-storm to SDF/LEX. Most of the evening models still indicate BWG should remain dry. Convection should affect SDF/LEX mainly between 7-13Z late tonight into Tue morning. The frontal boundary associated with this system will lift NE during the day tomorrow so any late day rain chances will be greatest at LEX. Brief MVFR conditions are possible in any convection. Winds will be variable tonight and then predominantly west with gusts up to 18-20 kts Tues afternoon. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update............MJ Short Term........13 Long Term.........13 Aviation..........AMS
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1101 PM CDT Mon May 8 2017 .UPDATED for 06Z Aviation Discussion... Issued at 1055 PM CDT Mon May 8 2017 && .SHORT TERM...(This evening through Tuesday) Issued at 307 PM CDT Mon May 8 2017 The surface low of interest is entering southwest MN this afternoon. Warm air advection in advance of this feature will spawn shower and thunderstorm development this afternoon and evening. Temperatures have warmed into the upper 70s and lower 80s in the thermal ridge axis just ahead of the trough from west central into south central MN, where dewpoints are creeping up toward the 60 degree mark. Most unstable CAPE values have increased to around 1500 J/KG this afternoon in said area, where 700-500mb lapse rates are circa 7.5 degrees C/KM. Therefore, any stronger cells that develop could be hail producers. The preferred model for convective evolution today was the HRRR 1km, which indicates the main window of shower and thunderstorm activity in MN will be between 6 pm and midnight, with lingering showers over west central WI overnight as the boundary stalls over northern Iowa. A few showers may linger near Eau Claire on Tuesday morning, but for the most part a dry day is expected with low cloud cover gradually decreasing (but being replaced by increasing mid level clouds from the west). Temperatures remain mild tonight mostly in the lower 40s to lower 50s, with cooler highs on Tuesday in the lower 60s to lower 70s. .LONG TERM...(Tuesday night through Monday) Issued at 307 PM CDT Mon May 8 2017 For the most part the latter portion of the forecast period looks to be quiet with the bulk of precipitation chances staying to our south, although there will be better chances areawide toward the end of the period as we see the main baroclinic zone lift a bit farther north. Some shower activity could work up to around I-90 or so wednesday, although the main precipitation looks to be well to the south closer to the warm front that will extend from the southern plains into the mid-Mississippi Valley. High pressure from Canada will assert itself Wednesday night into Friday, helping to displace the baroclinic zone and any chances for precipitation farther south, so dry weather and fairly seasonable temperatures can be expected. By later Friday into Saturday the western ridge looks like it will start to push eastward, which will help to tighten the northwest- southeast oriented temperature gradient while a northern stream shortwave trough drops southeast along it. This should provide for a window of rainfall potential later Friday into Saturday before high pressure once again noses in from the north. After that point, the spread in the model solutions increases, with the 12Z GFS keeping a surface ridge over the area through Monday, while the ECMWF and Canadian solutions have sufficient warm advection and some elevated instability to bring precipitation chances back into the area. For now there isn`t much reason to deviate much from a blended solution, which results in the inclusion of chance PoPs over most of the area later Sunday into Monday. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) Issued at 1055 PM CDT Mon May 8 2017 VFR with MVFR Cigs possible. Forecast guidance continue to indicate 1500 to 2500 ft ceilings will develop tonight, but took a more optimistic approach and raised them up to VFR. Did add mention of fog at KRNH and KEAU. Winds will become northerly and northwesterly overnight as a low pressure system moves across the region. KMSP... Last area of thunderstorms will pass through the region by 0430Z and should not have any other precipitation after that through the end of the TAF period. Forecast guidance hints at MVFR Cigs across the region later tonight, but kept the TAFS VFR at this time. /OUTLOOK FOR KMSP/ Wed...VFR. NW wind 5-10 kts. Thu...VFR. N wind 5-10 kts. Fri...VFR. N wind 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ SHORT TERM...LS LONG TERM... AVIATION...JRB
Area Forecast Discussion
National Weather Service Omaha/Valley NE
348 PM CDT Mon May 8 2017 .SHORT TERM...(Tonight through Thursday) Issued at 325 PM CDT Mon May 8 2017 Forecast concerns will continue to be isolated thunderstorm chances this evening then increasing rain and thunderstorm chances Tuesday night through Thursday morning. Thunderstorms indeed developed overnight in the expected area from far northeast Nebraska into western Iowa and points east. Local rain amounts were generally light with a trace to a few hundredths of an inch reported at Harlan, Red Oak, and Clarinda, Iowa. Farther east...half inch hail was reported in DMX`s area at Bridgewater and a public report of 2 inches of rain at Jamaica in Guthrie Co. The clouds thinned and with southwest winds at 10 to 20kt... temperatures have warmed into the upper 80s and lower 90s ahead of an approaching cold front. The winds have switched at KOFK/KLCG/KBVN. GOES-16 satellite imagery show a few puffy cumulus clouds trying to develop ahead of this boundary. The most recent Experimental HRRR has a narrow one-county wide area of isolated thunderstorms from 00Z to 02Z. The RAP hints at something isolated this afternoon into the early evening with the front in combination with the h5 trough moving across the Northern Plains. The NAM/EC are mostly dry and the GFS is a bit more aggressive. The latest SPC meso-graphics show 1000-1500J/kg MLCAPE with weakening inhibition to -25J/kg ahead of the front. Heating and the front should be enough to get a few storms going, however these should diminish with the heating. Included an isolated tsra mention early this evening with the front. The shortwave passes to the east...however the push of the surface front slows...thus should still in our CWA Tuesday morning. Lows tonight should be in the mid to upper 50s north, however in the lower 60s south. The closed h5 low over CA is a slow mover and is over southern AZ Tuesday and New Mexico Wednesday. Tuesday will have more clouds, however the forcing for ascent does not really move into the area until Tuesday night and Wednesday. There may be an isolated storm near the frontal boundary, however the better chance will be with the mid and upper level support Tuesday night into Wednesday where showers and thunderstorms becoming likely for parts of the outlook area. Highs Tuesday should be in the 70s/80s and Wednesday in the 60s/70s. The combination of the surface front in Kansas and the closed low tracking from New Mexico into the Central Plains will set the stage for locally heavy rain Wednesday night across parts of Kansas into Missouri. The northern part of the forecast area should be mainly dry after Wednesday night, however the rain will linger in the south Through Thursday. .LONG TERM...(Thursday night through Monday) Issued at 325 PM CDT Mon May 8 2017 A drier period is forecast for Friday and Saturday with highs in the 70s. Sunday could bring a few showers and thunderstorms however there is still poor model agreement at forecast time. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1202 PM CDT Mon May 8 2017 There is now enough of a chance of TSRA at KOMA late this afternoon and evening to where a VCTS mention has been included in the 18Z TAF. Kept ceilings at or above 8000 feet for now, but will amend forecast if needed based on what happens. A cold front will sink southward through the area this afternoon and evening, with winds shifting to northwest and then north with frontal passage. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Zapotocny LONG TERM...Zapotocny AVIATION...Miller
Area Forecast Discussion
National Weather Service Las Vegas NV
555 PM PDT Mon May 8 2017 .SYNOPSIS...Warmer temperatures with just a few showers lingering across northern portions of the area Monday before additional showers and thunderstorms move back into the area Tuesday into Wednesday on the back side of a departing low pressure system. Winds will strengthen briefly Tuesday morning, particularly along the Colorado River, and diminish by the evening. Warming and drying conditions expected after Wednesday. && .UPDATE...First wave of isolated thunderstorms across southern Mohave County dissipating as it nears Lake Havasu City currently. Radar shows next area getting ready to move into southeast Mohave County east of Wikieup. HRRR plus 18z NAM and GFS show additional waves of showers along with a risk of isolated thunderstorms moving west across southern Mohave County. Updated to increase PoPs generally south of Interstate 40 and east of Highway 95 in San Bernardino County tonight. Will also be monitoring trends of ongoing precipitation across Esmeralda/Inyo and Lincoln Counties over the next few hours. && .PREV DISCUSSION...442 PM PDT Mon May 8 2017 .SHORT TERM... The cut-off low remains the weather maker for the short term. Lingering showers and a possible thunderstorm are likely in the northern portions of the forecast area tonight, these areas include eastern Sierra, Esmeralda County, and Nye County. Tuesday morning, chances for showers move to the southeast region of the CWA, primarily in northwest Arizona. By the afternoon, chances for shower and a possible thunderstorm spread into southern Nevada and southeast California as moisture wraps around the upper level low. Although precipitation has been underwhelming for this particular system, QPF still sits around a tenth of inch for the Las Vegas valley. Warming in the mid and upper levels should keep snow levels above the 10000` mark. In terms of wind, models indicate a frontal feature associated with the upper level low that will propagate from northwest Arizona into southern Nevada Tuesday morning. This front will usher in strong south winds, particularly along the Colorado River Valley. Wind speeds will peak during the afternoon ranging between 25 to 35 mph and gusts between 35 to 45. A Lake Wind Advisory has been issued for Lake Mead and Lake Mohave as hazardous boating conditions are likely to develop in the morning and afternoon. If these winds develop earlier in the morning, patchy areas of blowing dust will likely develop and reduce visibilities. Winds should settle down tomorrow evening and remain light through Wednesday night. Temperatures should remain a few degrees below normal Tuesday and Wednesday, with cloud cover Tuesday keeping the diurnal temperature range around 10 degrees. .LONG TERM...Thursday through Monday. A dry and persistent breezy to windy pattern with near normal temperatures appears to be developing for the weekend into early next week. The medium range models are in good agreement at depicting an amplified ridge migrating over the southwest states and Intermountain Region Thursday ahead of a broad closed low over the Pacific Northwest. The base of this low is then forecast to swing over California and Nevada Friday and hold through the weekend as the system circulates over the northwest states. There are various differences in the models with respect to shortwaves rotating through the low along with the placement and depth of the closed circulation. However, it looks likely that this broad low will park over the northwest states and produce periods of gusty southwest winds over much of our forecast area through the weekend with highs generally in the upper 80s to mid 90s across the deserts. && .AVIATION...For McCarran...Winds expected to remain light and follow a diurnal pattern this evening, with a westerly wind developing after sunset. Tuesday morning winds will be light and northeasterly before a shift to southerly around 19Z to 21Z. With the southerly shift, winds will strengthen to around 10 to 13 kts with gusts between 15 to 25 kts. Gusty winds may produce areas of blowing dust reducing visibilities Tuesday morning. Chances for showers increase Tuesday and are expected last through Wednesday, with the best chance for shower development occurring after 00Z Tuesday. Skies are expected to be broken with CIGs around 8000`. For the rest of southern Nevada, northwest Arizona and southeast California...Gusty south winds of 35 to 45 mph expected Tuesday morning along the Colorado River and will progress into southern Nevada by the afternoon, with gusts decreasing to 15 to 25 mph. Areas of blowing dust are possible with gusty winds. Showers expected for northwest Arizona in the morning and spreading into the southern Nevada and southeast California by the afternoon. Overcast conditions expected to develop with CIGs dropping to about 6000` for northwest Arizona by noon. Elsewhere, CIGs should be around 10000`. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ UPDATE...Pierce SHORT TERM/AVIATION...Boothe LONG TERM.............Adair For more forecast information...see us on our webpage: or follow us on Facebook and Twitter