Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/21/19


Area Forecast Discussion
National Weather Service Aberdeen SD
1032 PM CDT Fri Sep 20 2019 .UPDATE... Issued at 1029 PM CDT Fri Sep 20 2019 Convection is expected to continue to expand into parts of north central South Dakota, as such increased the severe thunderstorm watch to cover Corson/Dewey with warned storms just upstream. && .SHORT TERM...(This Evening through Saturday Night) Issued at 245 PM CDT Fri Sep 20 2019 Main challenge through the short range centers around tonight. Sfc front/dry line will continue to move only very slowly through the afternoon, but should pick up forward momentum by mid evening as mid level trof starts lifting northeast out of the Rockies, and into the Northern Plains. A few CAMS still show isolated convection forming out ahead of the front through early evening, so will keep slight chc pops going across the region for the late afternoon/early evening. That said, the latest HRRR runs have backed off on pre-frontal convection to some degree. More widespread convection appears possible overnight as front traverses the forecast area. An unstable to very unstable airmass across the area would support severe storms, however, deep layer bulk shear will be lacking, and suggests cells could favor pulse severe. Large cape profiles would support large hail potential with early evening activity. The main threat from the later activity will probably be strong wind as mid level winds from approaching trof overspread the CWA, and force any cells into line segments. Heavy rain remains a threat given way above normal PWATs. With only isolated activity anticipated early, and progressive storms expected later in the evening, will hold off on any hydro headlines at this time. Behind the front, conditions will turn cooler and less humid for Saturday/Saturday night. Lingering showers are possible Saturday in the north and east. Saturday night should be tranquil and cool. Did beef up winds from blended guidance given the deep mixing with afternoon heating. Also boosted temps a touch based on deep mixing of a still warm airmass. .LONG TERM...(Sunday through Friday) Issued at 245 PM CDT Fri Sep 20 2019 Looks like another brief warmup in store for Monday as upper level ridging moves across the region. MOS guidance was warmer than NBM, so used a CONSMOS blend for Monday`s highs to get readings a couple degrees higher. Also used a CONSMOS blend for low temps Wednesday night as a surface high moves across the area, which was better at capturing the cooler temp potential compared to NBM. Winds on Wednesday were increased a bit towards CONSMOS values as both the GFS and EC agree fairly well in there being breezy/windy conditions within a tight pressure gradient. Otherwise, conditions look mainly dry to start out the period on Sunday. Shortwave energy looks to cross the region mid-week, bringing a chance of precip. Potential for a stronger system by the end of next week, but still plenty of time for models to sort things out. As for temperatures, will see a cooldown mid-week as a cold front will bring in cooler temperatures. Looking at 60s for highs for the latter half of next week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday Evening) Issued at 544 PM CDT Fri Sep 20 2019 We should have VFR conditions for the most part. Tracking weak storms near KMBG (and kind of by KABR) through the afternoon, before another round of storms may come up from the southwest and impact KPIR. After that, there is some uncertainty but storms will continue east and possibly impact KABR/KATY. Winds go from southerly to westerly behind the front for drier conditions for the most part Saturday. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...Connelly SHORT TERM...TDK LONG TERM...TMT AVIATION...Connelly
Area Forecast Discussion
National Weather Service La Crosse WI
1047 PM CDT Fri Sep 20 2019 .SHORT TERM...(This evening through Saturday) Issued at 312 PM CDT Fri Sep 20 2019 At 3 PM, skies were mostly to partly sunny across northeast Iowa, and mostly cloudy across the Upper Mississippi River Valley. Temperatures ranged from the mid-70s to mid-80s. For late tonight and Saturday morning, the remnants of Imelda will move northeast through the area. This system will bring with it a band of showers and storms. With preciptable water values running close to 2 inches and warm cloud layer depths over 4 km, these showers and storms will be very efficient rain producers. Fortunately, it looks like these storms will be rather progressive, so this will limit the flooding threat. .LONG TERM...(Saturday night through Friday) Issued at 312 PM CDT Fri Sep 20 2019 On Saturday night, a cold front will move southeast through the area. This front will move the fastest north of Interstate 90 and much slower south of this Interstate. Clouds will likely limit the instability. While the 0-1 km ML CAPES will be up to 1500 J/kg, the deep shear will be mainly along and post frontal. Most of the CAMs are not that impressive with the storms along this front. However, the latest HRRR would suggest that there may be a few isolated supercells along this front. The main threat would be large hail and gusty winds. The main heavy rain threat will be in southwest Wisconsin and the eastern portion of northeast Iowa where precipitable water values will be around 2 inches and warm cloud layer depths will be in the excess of 4 km. On Sunday, a shortwave will round the base of a longwave trough moving through the region. It is unclear whether this will bring additional heavy rain to Grant County in southwest Wisconsin. From Tuesday night into Wednesday, another longwave trough will move through the region. Moderate to strong moisture transport will be found ahead of this system. Precipitable water values will quickly climb to around 1.6 inches. While 0-1 km ML CAPES will climb up to 1500 J/kg, the 0-3 and 0-6 km shear looks to be weak, therefore severe weather is not anticipated at this time. On Thursday night and Friday, there will be another surge of moisture into the region as a shortwave trough approaches the region. Precipitable water values will climb into the 1.6 to 2 inch range. This may result in another bout of heavy rain for the region. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1046 PM CDT Fri Sep 20 2019 VFR conditions expected at the TAF sites through early Saturday morning until a push of low level moisture arrives towards daybreak with an approaching disturbance. This will lead to a quickly developing cloud deck with low end MVFR to IFR ceilings. Not anticipating much in the way of convection associated with this passing feature, but limited instability may support some showers and perhaps a rumble of thunder or two through ~14Z. Due to expected limited coverage, have only gone with VCSH in the TAFs. IFR cigs then expected through early afternoon when daytime heating should initiate a slight rise to MVFR for the remainder of the period. There is a small chance for additional showers and storms in the afternoon, but potential activity looks pretty limited/unorganized due to weak forcing and some capping aloft. Have therefore stuck with just VCSH. A somewhat better chance for storms will come after 00Z Sunday as a cold front drops into the area, so have introduced VCTS Saturday evening. Southeast winds will gradually increase through early Saturday morning as the pressure gradient strengthens overhead, becoming more southerly by daybreak. Winds will turn gusty by mid-morning, especially at RST where gusts approaching 30 knots are possible through the afternoon. Gusts will diminish with sunset, but winds will remain breezy as they shift to the southwest ahead of the front. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Boyne LONG TERM...Boyne AVIATION...Kurz
Area Forecast Discussion...Updated
National Weather Service Billings MT
849 PM MDT Fri Sep 20 2019 .UPDATE... Made only minor adjustments for the update. Central part of forecast area was in a dry slot this evening, with a N-S line of thunderstorms over SE MT, and rain to the W of KBIL. 500 mb trough was over W MT/E ID/NW WY at 02Z while 700 mb low was further E with drier air riding N into the area from WY. 700 low will shift into W ND overnight...allowing rain to overspread the entire area. Noted RAP soundings had MUCAPES just below 1000 j/kg for much of the night over SE MT and Sheridan County. Effective Bulk Shear was high as well, but winds were backing with height due to cold advection around the system. 12Z HREF did have some helicity tracks over SE MT but these looked overdone thus far. So, kept thunder in the forecast in the SE and in the Sheridan Foothills, but did not have any strong storms mentioned. Elsewhere had just rain, with snow in the mountains. RAP soundings showed freezing levels dropping to just under 8000 ft AGL tonight. 700 mb gets pretty cold, with -3 degree C air moving into the W. While best dynamics will be over E MT with the jet, upslope N flow and decent QPF will support warning snow amounts in the Absaroka/Beartooth mountains. So no changes to WSW or the HWO which also mentions the heavy rain amounts for the area. Boosted winds up a little overnight and adjusted PoPs for current trends. Arthur && .SHORT TERM...valid for Sat and Sun... Upper low is currently sitting just south of Yellowstone park and is on a slow northeasterly trajectory that should take it over Sheridan county by midnight and into Carter county by sunrise tomorrow morning. Heaviest precipitation with this system will be to the north of this track from Livingston to just south of Billings to Baker/Ekalaka. Already seeing reports of around an inch of precipitation from Nye to Red Lodge and as far north as Columbus this afternoon. Expecting another half inch to inch and a half along this heavier precipitation band overnight into tomorrow morning. No big changes to the snow forecast and going Winter Storm Warning this afternoon, with 10 ot 18 inches of snow expected above 7500-8000 feet. Temperatures above 7000 feet are in the 30s at mountain reporting sites and radar shows the freezing level around 7700 feet at this time. The storm system will shift to the east tomorrow morning with gusty northwest winds building in behind it. Gusts over Sheridan county and across SE Montana could gust over 40 mph at times. While the heavier steady precipitation will taper off during the morning, isolated to scattered instability showers under the upper trough will continue into early evening. Sunday looks sunny with highs in the 70s. Chambers .LONG TERM...valid for Mon...Tue...Wed...Thu...Fri... Split flow over the western CONUS on Monday will mean little chance of any impact weather with only weak forcing and moisture available over our region, but we could see a few light showers over the mountains and foothills. Otherwise, a transition to faster zonal flow will bring dry conditions for our lower elevations thru Tuesday. Flow aloft will veer to the NW Tuesday night and Wednesday. As heights drop at midweek we will see an increasing chance of light showers in the NW flow. We could also possibly see our first gap wind highlights of the season at midweek. Mid level temps will fall enough to bring a risk of more snow showers for the high elevations. Information from ensembles analysis provides increasing confidence of a deep trough developing over the western CONUS toward the latter end of next week. This pattern change would lead to cool/wet weather setting up for our region beginning Thursday and potentially lasting thru the weekend. Temperatures will begin near or a little above normal Monday thru Tuesday, then fall below normal thereafter. Significantly cooler temps are then possible by next weekend. BT && .AVIATION... Conditions will range from MVFR to LIFR across the area into Saturday morning in rain and thunderstorms. Expect gusty WNW surface winds tonight through Saturday as well. Conditions will improve to VFR across the area by Sat. afternoon. Widespread mountain obscurations will continue through Sat. morning and decrease in the afternoon. Arthur && .PRELIMINARY POINT TEMP/POPS... Sat Sun Mon Tue Wed Thu Fri ----------------------------------------------------------- BIL 048/064 046/073 049/075 051/075 049/065 046/064 043/059 +6/W 20/U 01/B 10/U 22/W 22/R 44/R LVM 041/061 040/070 043/070 044/070 042/064 039/060 037/056 96/W 10/U 12/W 10/N 22/W 23/R 45/O HDN 046/062 043/072 046/075 047/074 046/064 043/064 042/060 88/W 20/U 01/B 00/U 22/W 22/R 34/R MLS 050/063 045/073 048/076 050/071 046/063 043/063 042/060 88/W 10/U 00/U 00/B 21/B 22/R 33/R 4BQ 046/062 042/071 044/076 047/073 045/063 042/065 041/061 79/W 20/U 01/U 10/U 21/B 21/E 23/R BHK 048/062 043/071 046/076 048/070 044/061 041/062 040/060 9+/W 20/U 00/U 00/B 21/B 22/R 33/R SHR 042/060 038/071 042/074 043/073 043/063 039/064 039/061 78/W 30/U 01/B 10/U 22/W 22/R 33/R && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Winter Storm Warning in effect until noon MDT Saturday FOR ZONE 67. WY...None. && $$ weather.gov/billings
Area Forecast Discussion
National Weather Service Goodland KS
922 PM MDT Fri Sep 20 2019 .UPDATE... Issued at 922 PM MDT Fri Sep 20 2019 Stronger gusts near 35 to 40 mph are showing up across portions of the CWA. Going forecast was updated to reflect the increased wind conditions. && .SHORT TERM...(This evening through Saturday night) Issued at 230 PM MDT Fri Sep 20 2019 Overview: Southerly flow aloft will transition to southwesterly flow aloft over the Central Plains in this period -- as an upper level low invof Yellowstone (today) lifts northeast through the Dakotas (Saturday) into Manitoba/Ontario (Saturday night). Through Tonight: Breezy southerly flow on the eastern periphery of a lee cyclone in northeast Colorado will persist through this evening, gradually veering to the SSW-SW-WSW overnight as the cyclone weakens and progresses into central Nebraska. Simulated reflectivity forecasts via the HRRR suggest that isolated convection will develop between Lamar-Tribune around 20-21Z (presumably in association with low-level convergence on the eastern periphery of the lee cyclone) -- with activity progressing northeast toward Colby/Oakley through ~00Z. Visible satellite imagery and radar data show agitated Cu and the onset of faint reflectivity echoes ENE of Lamar at 20Z, lending support to the aforementioned HRRR forecast. Though mid-level lapse rates are relatively weak (6.5-7.0 C/km), instability is marginal (500-1000 J/kg MLCAPE), and forcing is largely confined to low- level convergence, effective deep layer shear on the order of 30-40 knots suggest a conditional potential for organized updrafts /low- end isold severe potential/ may exist between 21-01Z. Sat-Sat night: Shortwave energy digging southward through Nevada this afternoon will round the base of a broad trough over the Intermountain West on Saturday, ejecting ENE across the Rockies Saturday night. A lee cyclone will develop in advance of this feature in southeast Colorado on Sat, progressing eastward into Kansas Saturday night. With the aforementioned cyclone progged to track eastward invof Hwy 50 -- and an attendant thermal/moisture boundary extending northeast from Ulysses-Garden City-LaCrosse- Russell, surface based convection is generally anticipated to remain south and east of the GLD county warning area during the afternoon, though elevated convection will be possible in advance of the progressive shortwave -- on the N-NNW periphery of the aforementioned cyclone Sat eve/night, primarily in northwest KS. .LONG TERM...(Sunday through Saturday) Issued at 211 PM MDT Fri Sep 20 2019 The extended forecast begins with an upper level trough progressing eastward into the region and a surface low over western and central Kansas. We may see a few lingering showers in our eastern counties early Sunday morning as the system moves out of the region, but the better chance for rain will be in the prior time period. Monday, weak ridging over the Central High Plains will allow our temperatures to warm to near normal with dry conditions across the region for the daytime hours. An upper level low over western Nevada will push south into southern California and western Arizona. Going into the evening and overnight hours, a few isolated showers or thunderstorms will be possible as a shortwave trough moves through the region. High temperatures will be in the 80s and overnight lows going into Tuesday morning will range from the low 50s to low 60s. Tuesday, the flow will become northwesterly over the Tri-State region. Both the GFS and the ECMWF show pretty good agreement on the upper low becoming cut off Tuesday and remaining over southern California and Arizona through Wednesday evening. The low will begin to track to the northeast through the day Thursday. Was okay with a few isolated storms in the forecast in the evening as the system begins to move into the forecast area. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 518 PM MDT Fri Sep 20 2019 The passage of a frontal boundary thru the forecast period...is going to allow for VFR/dry conditions with a mix of scattered mid clouds and SKC. Winds for KGLD...SE 25-35kts thru 04z Saturday...then SW 10-20kts. By 07z...NW 10-15kts becoming N by 12z. A shift to the NE around 10kts will occur from 18z onward. Winds for KMCK...SE 15-30kts thru 06z Saturday...then SW 10-20kts. By 10z...WNW 10-15kts becoming NNW by 15z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JN SHORT TERM...VINCENT LONG TERM...AW AVIATION...JN
Area Forecast Discussion
National Weather Service Key West FL
919 PM EDT Fri Sep 20 2019 .DISCUSSION...In the middle and upper levels(700-200 mb), latest available satellite imagery overlaid with model streamline analysis as of 800 pm, depicts a sharp but narrow middle and upper trough axis that is positioned from the NW Atlantic well east of Atlantic Canada south southwest thru Florida and the Keys down to a slowly pinching TUTT cell over the Western Caribbean Sea. West of that the center of a deep and warm anticyclone is positioned across Northeastern Old Mexico, with the eastern periphery of this expansive ridging reaching the Eastern Gulf of Mexico and the Yucatan Peninsula. Well to the east of the sharp trough, the center of another deep and warm synoptic scale anticyclone was positioned near 30N 50W with an attendant ridge axis extending southwest to just west thru north of Hurricane Jerry. At 800 pm, the center of Hurricane Jerry was located near 19.9N 62.5W, which is about 125 miles NNE of Anguilla in the Northern Leeward Islands. At the surface and in the lower to middle levels(Surface to 700 mb). latest available marine and land surface observations and analysis as of 800 pm, detail near 1030 mb surface ridging centered from Cape Hatteras to Western South Carolina. 4-panel CIRA LPW layered precipitable water delineates the leading edge of deep moisture with columnar PWAT averaging between 2,00 and 2.25 inches approaching the extreme SE Florida Peninsula as well as the Eastern Florida Straits and just shy of the Upper Florida Keys attm. Well upstream of that Keys exists a strong tropical wave axis at the longitude of the Windward Passage. The combination of these features is resulting in an unusually tight MSLP gradient, resulting in strong breezes. As such, the 00Z evening sounding at KEYW illustrated .CURRENTLY...As of 800 pm, skies were partly to mostly cloudy across the islands and surrounding waters. Radar detects scattered showers and a few thunderstorms which have began to infiltrate the area from the east in the last few hours. Individual shower activity continues to move at an average speed of about 25 knots, but the stronger cells are moving between 30 and 35 knots, which has required continual issuances (late this afternoon and thus far this evening) of marine weather statements and a few special marine warnings in which some wind gusts over 40 knots appear likely. Temperatures across the islands outside of the fast moving shower activity are in the lower 80s, but dropping into the upper 70s in some showers. C-man stations along the Florida Reef as well as at Smith Shoal Light and in Florida Bay are averaging east at 20 to 25 knots with occasional gusts over 30 knots. Occasional gusts between 30 and 35 knots are more likely occurring across the deeper Florida Straits waters. .SHORT TERM...Overnight and Saturday, the strong 1025-1030 mb surface ridging centered over Eastern North Carolina will remain in place overnight thru the day on Saturday. Upstream of the Keys as mentioned above, moisture will deepen in the column from 850 to 500 mb later tonight and during the day Saturday. Also, intermediate runs continue with model time height analysis exhibiting decent 850-700 mb maxima in the omega fields. Given this in concert with weak cyclonic curvature, very strong surface/low level confluence always takes shape, resulting in coverage of numerous showers. This will be the case for at least the next 36 hours. So will be increasing the 12 hour rain chance (pops) for tomorrow, as HRRR and other meso- scale models increasing coverages of these fast moving showers. For the rest of tonight, the ongoing, likely, 60 percent pops looks good for the overnight period (thru 6 am), but as we approach dawn and the column continues to moisten with PWAT exceeding 2.00+ inches, will increase rain chances from high chance, 50%, to likely, 70% for the day on Saturday (6 am to 6pm). Also, given current observations, will just increase winds over the islands to between 20 and 25 mph for the overnight period. And although these will be the sustained winds over the islands, it is important to remember that this will be outside of any and all showers and isolated storms. Occasional gusts between 35 to 45 mph will be likely in some of fast moving showers and isolated storms. Issuances of significant weather advisories for portions of the affected Keys Island Chain islands will occur when an available weather station(s) sensor reports any wind gusts that exceed 45 mph. No other changes on this cycle. && .MARINE...Overnight and Saturday, Small Craft Advisory (SCA )conditions on all waters with very hazardous conditions expected. Winds will increase this evening to around 25 knots with occasional gusts exceeding 30 knots across all waters in the marine district this evening, except some portions of the waters may increase to between 25 to 30 knots with occasional gusts exceeding 35 knots. These conditions will continue during Saturday. In some isolated heavy showers and thunderstorms, wind gusts in excess of 40 to 45 knots will be possible. If radar detects these conditions, then a special marine warning will be issued. && .AVIATION...Strong east breezes with gusts commonly near 25 knots will continue through Saturday. Increasing coverage and intensity of fast-moving showers and eventually thunderstorms will be the other concern for the next 24 hours. At some time on Saturday, both island terminals are likely to see significant round(s) of thunderstorms accompanied by 1-3SM visibility in heavy rain, along with BKN cigs in the 020-030 range. Storms should also come with brief convective wind gusts near 35 knots. However, guidance is at odds with the most likely time on Saturday for thunderstorms. Some guidance focuses on Saturday morning, other guidance focuses on the afternoon, and others nearly all day. The TAFs currently reflect VCTS for weather starting at midnight tonight, but will have to wait for more timing certainty before adding TEMPO group(s) for thunder. Pilots should plan their Saturday flight operations for the possibility of active convective weather and the certainty of gusty winds. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...Small Craft Advisory until 5 AM EDT Saturday for GMZ031>035- 042>044-052>055-072>075. && $$ Public/Marine...Futterman Aviation/Nowcasts/Statements/Warnings....Haner Upper Air/Data Collection/Public Service......NB Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest
Area Forecast Discussion
National Weather Service Louisville KY
706 PM EDT Fri Sep 20 2019 ...Updated Aviation Discussion... .Short Term...(This evening through Saturday) Updated at 323 PM EDT Fri Sep 20 2019 Convection from earlier this morning into the afternoon has diminished for the most part. A few very light showers linger in our Bluegrass region, but otherwise we are dry. The next focus for any shower activity will be across southern Indiana toward sunset. The HRRR has been consistent in showing some isolated development by 21- 22z in that area. The latest mesoanalysis data shows around 1500- 2000 J/KG of SB CAPE up in that area, however any convection will likely be mitigated by a mid level inversion (~15000 Feet) evident on forecast and AMDAR soundings. As a result, have only included showers in the forecast and will leave thunder potential out. Some of these showers could spill into the Louisville metro after sunset so will mention a 20% pop along and north of I-64. Any shower activity should diminish before Midnight, with dry conditions persisting thereafter. Temps should drop back into the 60s for lows given modest radiational cooling conditions under mostly clear skies. Dry conditions will continue again tomorrow due to the upper ridge and a notable subsidence inversion evident on forecast soundings. A steady SW wind combined with 850mb temps around 16C should yield highs in the upper 80s and low 90s. Decided to lean on high side of guidance due to drought conditions and recent overachieving of temps. .Long Term...(Saturday night through Friday) Updated at 250 PM EDT Fri Sep 20 2019 The persistent warm, dry ridge of high pressure aloft from the southeastern U.S. into the lower OH Valley at the start of the extended period will get shunted southward temporarily as a strong shortwave trough moves across the upper MS Valley and Great Lakes states on Sunday and Monday. This system will drive a cold front southeast across the lower OH Valley and our area Sunday night and Monday. Widespread showers and t-storms associated with the front will occur well to our north and west on Sunday. However, as rain spreads southeast toward the upper ridge, expect a weakening trend in coverage and amounts over our area, where rain is much needed. Showers will become more scattered in nature. Based on current model solutions, expect rainfall amounts to vary from roughly around 0.25 inch in parts of southern IN to maybe around 0.1 inch south of the OH River to only a couple/few hundredths of an inch in south-central KY. Definitely no drought buster. Surface high pressure will build into our area Monday night and Tuesday with high temperatures closer to normal. Then, another broad shortwave trough is forecast to move across the northern U.S. states during the mid part of next week. This should drag another front southeast across the OH Valley roughly Wednesday night or Thursday, with only isolated to perhaps scattered showers possible in parts of our area. Again, at this time, it looks like little or no help with the drought. However, this frontal boundary should not make it too far south as the upper ridge begins to expand northward again. By the end of next week, all models show this pesky ridge back in control over the lower OH Valley and points southward, with a return to very warm to potentially hot temperatures next weekend into the start of the following week. && .Aviation...(00Z TAF Issuance) Updated at 705 PM EDT Fri Sep 20 2019 VFR conditions are expected this evening and during the overnight hours. Winds will generally be light out of the south to southwest. For Saturday, look for VFR conditions across the region with a diurnal Cu deck around 5-6 Kft AGL. Winds will be out of the southwest at 8-10kts. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Short Term...BJS/CSS Long Term....TWF Aviation.....MJ
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
642 PM CDT Fri Sep 20 2019 .SHORT TERM... (Through Late Saturday Night) Issued at 253 PM CDT Fri Sep 20 2019 No changes to the Flash Flood Watch. Moisture continues to surge northward into the region, evident in TSRA coverage over southern portions of the CWA. Storms should diminish with sunset, however, expect storms to linger a little longer than over the past couple of days. The focus of precip should shift to western, then northern, portions of the CWA as the LLJ increases. That said, with the vort max over southern MO into AR lifting into the region, going forecast may not have high enough PoPs far enough southeast. Models are also suggesting a band of showers lifting eastward through the central portions of the CWA around and just after sunrise. Some of the later cycles of the RAP have shifted this a little further north. As such, confidence remains on the lower end for timing and placement. Still expect precip to gradually diminish through the morning hours. After a lull in activity through much of the afternoon, expect precip coverage to increase across northern portions of the CWA during the late afternoon and persist through the overnight hours. Tilly .LONG TERM... (Sunday through Next Friday) Issued at 253 PM CDT Fri Sep 20 2019 Main focus continues early in the period. A confluent upper trof approaches the region on Sun with the surface cold front reaching northern portions of the CWA mid to late Sun morning. Moisture advection ahead of this front continues with PWs of 2+ inches. With the LLJ parallel to the front, training storms will be possible. These factors in addition to high freezing level and the high PWs, a threat of flash flooding exists for mainly the northern third or so of the CWA. However, will keep the watch as is due to continued uncertainty. With the available CAPE and deep layer shear ahead of the front on Sun, will need to continue to monitor a severe threat. The cold front is expected to push south through the area Sun night with rain coming to an end. After a dry Mon and most of Tues, the chance for rain increases again mid to late week. With differences among model solns, have kept PoPs low for now. Tilly && .AVIATION... (For the 00z TAFs through 00z Saturday Evening) Issued at 632 PM CDT Fri Sep 20 2019 Showers and storms will continue to diminish over the next few hours and we should have a quiet latter half of the evening. Precip chances will then return after midnight in central MO, pushing toward NE MO and west-central IL prior to sunrise. The highest precip chances will linger in these areas through much of the day tomorrow, though it does look like there may be a bit of a lull in storm activity in the early afternoon. Cigs are expected to dip into MVFR with these morning showers and storms, gradually increasing by the late morning. For east-central MO, SE MO, and southern IL, precip chances will be a bit lower, though activity is expected to be greatest in the morning before diminishing somewhat in the afternoon. That said, isolated storms are likely tomorrow afternoon, but confidence in these storms impacting a terminal is low. Obviously conditions will deteriorate for areas impacted by storms. BSH && .PRELIMINARY POINT TEMPS/POPS... Saint Louis 72 85 73 84 / 60 40 20 80 Quincy 71 79 68 73 / 60 70 90 80 Columbia 69 80 69 77 / 50 50 50 80 Jefferson City 69 82 70 79 / 50 50 40 80 Salem 67 83 70 86 / 60 10 5 60 Farmington 66 82 68 85 / 30 20 5 60 && .LSX WATCHES/WARNINGS/ADVISORIES... MO...Flash Flood Watch from Saturday evening through late Sunday night for Audrain MO-Boone MO-Callaway MO-Knox MO-Lewis MO- Marion MO-Monroe MO-Montgomery MO-Pike MO-Ralls MO-Shelby MO. IL...Flash Flood Watch from Saturday evening through late Sunday night for Adams IL-Brown IL-Pike IL. && $$ WFO LSX