Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/29/17


Area Forecast Discussion
National Weather Service Denver/Boulder CO
356 PM MDT Thu Sep 28 2017 .SHORT TERM...(This evening through Friday) Issued at 356 PM MDT Thu Sep 28 2017 Mountains will see isolated thunderstorms for the next few hours, as they are closest to the upper low spinning over Utah. The rest of eastern Colorado has come under drier flow aloft, leading to clearing skies across the plains this afternoon. Some light rain and drizzle continues on the far eastern plains which will continue for a couple more hours. Overnight, the clearing skies may allow radiational fog to form, especially over the South Platte River valley. On Friday, the upper low currently over Utah is forecast to be moving across northern Colorado and Wyoming. This will set off a round of convection to develop over the mountains and then move out over the plains. Temperatures will be a few degrees warmer than today`s highs. Enough instability may be present for a few thunderstorms to develop, especially over the mountains. .LONG TERM...(Friday night through Thursday) Issued at 356 PM MDT Thu Sep 28 2017 The last piece of energy from this later weather system will be lifting northeast across the forecast area into Friday evening. Scattered showers and a couple thunderstorms over the mountains will attempt to spread over the plains given the weak lift through the evening. However, overall the airmass is drier and some downslope component over the plains should limit both coverage and intensity. On Saturday and Saturday night, the nose of a powerful 120-140 knot jet will plow into the Great Basin. Strong upper level forcing in the left exit region of this jet will help precipitation production. Precipitation will also be enhanced across the mountains and western slope of Colorado given the increasing orographic flow. Snow levels start out initially high, around 10-11 thousand feet, but then lower to around 9000 feet by late Saturday night as cold advection sets in. This pattern is favorable for accumulating snow for the high country, so there`s potential for a few inches over the mountain passes with some travel impacts. A few showers or storms may spill onto the plains Saturday afternoon and evening given the upper level divergence and slightly unstable airmass. By Sunday, there is considerable divergence in the models. GFS and Canadian maintain that most of the energy will get caught up in the first wave and eject into the northern U.S. Plains. Meanwhile, the ECMWF drives a second stronger wave quicker into the Northern and Central Rockies, which would bring a good chance of precipitation and colder temperatures late Sunday into Monday. These are always very difficult systems to deal with ahead of time given the low predictability with the sharp north/south gradients in temps and QPF in these patterns. We are more confident an upper low will eventually retrograde into the Desert Southwest early next week. However, proximity of this low will be difficult to determine over the next several days. A warmer and drier southwest flow should eventually develop toward the middle of next week if the pattern unfolds as expected. However, considerable uncertainty still dominates this forecast period. A close to climatology approach for the middle of next seems reasonable for now. && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) Issued at 356 PM MDT Thu Sep 28 2017 A moist airmass will remain over the Denver area overnight with weak east to southeasterly winds. Clearing skies through the evening will allow for strong radiational cooling and make it possible for areas of fog to begin developing. The latest HRRR shows fog forming as late as 4 AM. Any fog that forms will take until mid-morning to lift out. The threat of showers appears to be over this evening as showers are presently forming over Grand and Larimer Counties, and moving northward. Tomorrow afternoon should see another round of showers develop over the foothills that move over the metro area as the main upper low is forecast to be moving over northern Colorado and Wyoming. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Dankers LONG TERM...Barjenbruch AVIATION...Dankers
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
858 PM CDT Thu Sep 28 2017 .DISCUSSION... Just made a few minor adjustments, but did not mess with the minimum temperature forecast. Overall, the temperatures are doing fine except where the rainfall has temporarily cooled the air. Some convection is still occurring near the boundary where the strongest moisture convergence continues, especially over the Northern Coastal Bend near the Bee-San Patricio County line. A weak cap is starting to build but there are likely some boundaries still around which will initiate some weaker convection overnight. HRRR model is showing much of the rainfall ending over the Victoria area near midnight. Not sure if this will be the case (looking at convection farther NE), so did lower POPs a bit out there but still with chance/scattered POPs for now as some of that convection will continue to weaken with increasing cap and decreasing CAPE. Not sure how much will be seen out to the west, but given that convection is still occurring north of the CWFA and is moving toward that area, did not mess with rain chances too much at this time. Overall the forecast was in pretty good shape so only some minor changes were done to the first period. No changes to the marine package at this time. && .PREVIOUS DISCUSSION... /Issued 611 PM CDT Thu Sep 28 2017/ DISCUSSION... See AVIATION discussion for 00Z TAFs. AVIATION... Am expecting the convection to end over the eastern areas by 03Z (VCSH with TEMPO SHRA); Laredo terminal more uncertain. For now at KLRD have just gone with VCSH with no TEMPO, and will monitor, as think the northerly winds will limit rain chances enough. Otherwise, with lots of mid and high cloud cover and the limited radiational cooling, do not think we will see much in fog but may see some MVFR/IFR conditions at KLRD before 12Z (and have included it in the TAF). Farther east, with the frontal boundary moving across, may see some MVFR CIGs AOA 14Z for a few hours, with VFR returning by early afternoon. Could have a repeat of showers in the afternoon, given the proximate boundary and plentiful moisture and instability, so again went to VCSH/TEMPO SHRA all terminals for the afternoon. Expect mainly NE winds through the period with 11 knots or less most of the time, perhaps a bit higher at KCRP with winds coming off the bay. PREVIOUS DISCUSSION... /Issued 336 PM CDT Thu Sep 28 2017/ SHORT TERM (Tonight through Friday Night)... Have cancelled the Flash Flood Watch for the Rio Grande Plains a few hours early. Although additional sct shra`s and a few tsra`s are expected, widespread heavy rainfall with high QPF values is not expected tonight or Friday. QPF values will generally be 1/4 of an inch or less across the CWA. A few locations may see amounts approach an inch. Models prog that a pool of deeper moisture will move across the NE CWA this afternoon/evening. Low level moisture convergence is also progged to strengthen along the coast through tonight due to a weak coastal trough, and an embedded upper level short wave is expected to slowly track NE across the west then north portions of the CWA. Therefore, increased the pops for the NE CWA for this evening, while also showing a trend of decreasing pops across the southeast CWA as current convection over the Coastal Bend pushes farther inland. After midnight, moisture/sct convection is expected to shift farther south along the coast. Also, kept high end chc pops across the west through tonight due to the proximity to the short wave/increasing omega values and deeper moisture. A chc of convection continues on Fri as a weak cold front approaches the area, deeper moister pools across S TX and the upper short wave continues its slow track across the region. Not much in the way of CAA with this front nor a wind shift as sfc winds are already northerly due to the inverted coastal trough. The drier airmass associated with the weak cold front is expected to slowly advect into S TX Fri night. Precip chcs are expected to decrease from NE to S and SW. LONG TERM (Saturday through Thursday)... Saturday and Sunday looks dry and pleasant with a northeast low lvl flow across the area. Moisture increases on Monday as inverted trough forms along the coast and a deep easterly fetch sets up across the northern Gulf. PWATS rebound to 2.25-2.45 inches Tue-Wed and thus bumped up accordingly to the 30-50% range. Some drying is expected thereafter as deep layer ridge builds aloft and ENE flow redevelops over the area. Temperatures will generally be near normal during the period. There is a potential for minor tidal overflow much of next week per latest ESTOFs run which indicates surge values up to 1.6`. && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 75 88 73 89 70 / 20 50 20 20 10 Victoria 73 86 68 87 66 / 40 40 10 10 10 Laredo 72 86 69 87 70 / 50 40 40 20 10 Alice 73 88 70 89 68 / 40 50 20 20 10 Rockport 76 87 73 88 73 / 30 40 20 10 10 Cotulla 72 84 69 87 67 / 50 40 30 10 10 Kingsville 74 89 72 90 69 / 30 50 20 20 10 Navy Corpus 79 87 75 87 76 / 30 30 20 20 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ GW/86...SHORT TERM
Area Forecast Discussion
National Weather Service State College PA
1153 PM EDT Thu Sep 28 2017 .SYNOPSIS... After a long stretch of summer-like warmth and humidity, more seasonal conditions will be experienced into the weekend. A return to above normal temperatures will occur by the middle of next week as another unseasonably strong ridge of high pressure sets up over the eastern US. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... A layer of low clouds is dropping south through the northern mountains. Forecast soundings are conflicted as to whether they will break up and dissipate under the NW flow, or whether they will hang tough under the strengthening subsidence inversion. If clouds do continue to spread SE and do not break up, low temp forecasts could be in jeopardy. I did lean toward the clouds breaking up as we get deeper into the evening looking at RAP forecast RH fields. Weak ridging building over the area clearing skies and and light winds should make for efficient radiational cooling with temperatures dropping into the 40s and 50s, right where they should be for this time of year. Some valley fog formation is possible across northern valleys close to daybreak. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... A shortwave will traverse across the Great Lakes tomorrow. The greatest chances of shower activity will be closest to the NYS border. Moisture is limited with this feature and expect low rainfall totals with many locations will not see any precipitation. With cool temperatures aloft and more cloud cover, high temperatures will be at or a few degrees below average. System moves out of area later Friday night bringing another cool start to the day on Saturday. && .LONG TERM /SATURDAY THROUGH THURSDAY/... *Crisp, autumn air to sweep into the area through Sunday *First fall frost likely for the first morning of October 2017 (Northern Mountains of PA) *Seasonable, then much above normal temperatures return for the middle and latter part of next week A refreshing and much cooler fall airmass will move into the region for the upcoming weekend as a sprawling area of high pressure (1030-1032 mb) settles SE from the Upper Great Lakes region. Some areas of bkn-ovc morning clouds Sat (along with the chc for a few brief showers - mainly across the northern and eastern counties of the CWA) will improve to mostly sunny skies for Saturday afternoon. A gusty 20-25 mph breeze into the early afternoon hours Saturday will make it feel quite chilly (based not only on the apparent temp, but accentuated by the steamy high temps in the 80s that we`ve grown familiar with over the past week). The wind will diminish steady from the mid afternoon and go nearly calm by midnight Sat night, setting the stage for likely the coldest night since late in the Spring. As this high moves close to our CWA and rather sharp ridging/warming aloft builds east from the Nation`s Midwest very dry air and stable lapse rates will lead to very little if any cloud cover Sat night through Monday (outside of some fleeting low clouds as early morning fog briefly lifts to a thin stratus deck). The core of the sfc high will be right over the region Sunday, and the early morning hours afford the best chc for some frost (over the upcoming week) across the Northern Mtns of PA with min temps in the low to mid 30s there. Elsewhere lows will by mainly in the upper 30s throughout the central ridge and valley region, and l-m 40s in the southeast. Outside of the spotty light showers possible Sat morning, no rainfall is expected until Thu Oct 5th, and even that appears quite light, and 0.10 of an inch or less with a northern stream wave and cold front. Rainfall deficits are running 50 to 75% below normal across most of central PA over the last 30 to 60 days. At IPT, September 2017 is likely to rank just outside of the top-10 driest September`s on record. Mont-to-Date total rainfall of 1.17" at IPT is tied with 1995 as the 11th driest September on record. Temperatures will rebound next week as upper level heights rise downstream of mean troughing over the northern Rockies. The 12Z GEFS holds onto flatter ridging aloft from the Lower Miss Valley to the Mid Atlantic Region (leading to a continuation of warm and dry weather through next Friday), while the EC/ECENS displays an upper ridge sharpening much more across the plains states, and a shot of cooler air following the aforementioned Thursday cold front. Both Maxes and Mins could climb to 10 deg F above normal based on the GEFS that shows rather minimal temp spread out at days 6-7. The EC cools it down by Friday. && .AVIATION /04Z FRIDAY THROUGH TUESDAY/... VFR continues to dominate. Winds have slackened and winds at BFD have gone calm. That will further increase the likelihood of reducing conditions at BFD between 07Z to 14Z. However a mid stratocu deck has formed so this should reduce chances for IFR vsbys. However there is still a decent probability for MVFR to IFR cigs. The other TAF sites still have persistent north to northwesterly flow. As temperatures cool and the inversion overtakes the region these winds should go calm. However most regions should be dry enough for reducing cigs/vsbys to be avoided. The expectations will be BFD, JST and possibly IPT. These conditions should form after 07Z. Conditions should improve as the inversion erodes by mid morning Friday. Outlook... Fri...Evening low cigs/showers possible KBFD/KJST. Sat...AM low cigs possible KBFD/KJST. Sun and Mon...Mainly VFR conditions. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...Ross LONG TERM...Lambert AVIATION...Ceru
Area Forecast Discussion
National Weather Service Dodge City KS
708 PM CDT Thu Sep 28 2017 .UPDATE... Issued at 707 PM CDT Thu Sep 28 2017 Light rain showers are making decent eastward progress this evening, and pulled slight chance/chance pops east to the eastern border to cover for the next few hours. Most locations will receive a trace to 0.05 inch at most. && .SHORT TERM...(This evening through Friday) Issued at 222 PM CDT Thu Sep 28 2017 Precipitation that has been across eastern Colorado all day long as moved very little. KDDC WSR-88D is starting to show power returns across far SW Kansas. Think this activity will slowly drift east, but will weaken with time. Another vortmax rounding the base of the large trof to our west might start additional activity through the overnight, but confidence on this is not high. Generally, if it does rain, it should be mainly west of Highway 283. Otherwise, a fairly quiet night is expected other than the showers. Lows in the upper 40s to lower 50s are expected. .LONG TERM...(Friday night through Thursday) Issued at 222 PM CDT Thu Sep 28 2017 For Friday, there is about a 30 percent chance of showers, but any activity should be light in terms of QPF. Highs will range from 60s west to 70s east. The warm air advection pattern will continue through the weekend with increasing highs. Widespread 80s are expected by Sunday. The weekend will be windy too as the lee trough deepens. A front may skirt across northern Kansas late Sunday. Much of the precipitation looks to be north of the forecast area. Beyond this, warm and breezy conditions look to continue into next week. The 12Z EC is showing a strong cold front next Wednesday. Time will tell as this is a new solution compared to yesterday. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 600 PM CDT Thu Sep 28 2017 VFR will prevail at all airports through Friday. That said, a 4-8k ft AGL overcast will persist through the TAF period. Some occasional MVFR cigs are possible at times west of GCK and west of LBL. Light rain showers near GCK and LBL will diminish in coverage as they spread east. Latest HRRR and 18z NAM suggest scattered light rain showers will persist across SW KS well into Friday morning, with possible renewed development near LBL around 12z Fri. As such, blanketed a VCSH mention through most of this TAF forecast period. Any rain will be light with aviation impacts minimal. Light north winds this evening will become light and variable overnight, as 1026 mb surface high settles to near GCK by 12z Friday. As this high moves SE of SW KS, expect winds to trend SEly near 10 kts by Friday afternoon. && .PRELIMINARY POINT TEMPS/POPS... DDC 53 69 53 74 / 30 30 30 30 GCK 51 63 52 72 / 40 40 30 30 EHA 49 61 51 71 / 50 60 30 30 LBL 50 67 52 72 / 40 30 30 30 HYS 53 71 55 73 / 30 20 30 30 P28 55 74 55 75 / 20 20 20 20 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Turner SHORT TERM...Sugden LONG TERM...Sugden AVIATION...Turner
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
852 PM CDT Thu Sep 28 2017 .UPDATE... The Flash Flood Watch for our southwestern counties has been allowed to expire. While we do expect additional rain tonight over the southwestern portion of our region, heavy rainfall and flash flooding is not anticipated. Radar data shows mainly scattered showers along with a few thunderstorms ongoing for areas east of the I-35/I-37 corridors. Elsewhere, light stratiform rain continues across the Hill Country, southern Edwards Plateau and Rio Grande plains. A combination of the HRRR and SPC SSEO data seem to capture the ongoing activity and we will follow a blend of these solutions for tonight. This will result in an increase in rain chances east of I-35/I-37 for the next few hours. We have already seen some impressive rainfall rates in a few locations, with measured amounts near 2" per hour. Some minor flooding may result from these rainfall amounts, but this is expected to be confined to areas that have seen the least amount of rainfall over the last several days. With the loss of daytime heating, we should see much less in the way of deeper convection and thus a decrease in rainfall rates from late this evening the overnight hours. && .PREV DISCUSSION... /ISSUED 659 PM CDT Thu Sep 28 2017/ AVIATION.../00Z_TAFS/ Isolated to scattered showers and thunderstorms are occurring along and east of a T20 to AUS line where a weak front and/or differential heating boundary is located. Lightning will be very occasional near AUS as a weak inversion at 17-19 kft appears to generally be limiting the depth of convection there. Scattered showers are ongoing west of the boundary, including at SAT and SSF. Showers and thunderstorms should begin to dissipate after sunset, after which ceilings should quickly lower to MVFR at the I-35 TAF sites by 4-5Z and eventually IFR ceilings and visibilities at some point before sunset. There is quite a bit of uncertainty when exactly this will happen and it is possible that patchy fog will cause conditions to lower to IFR before ceilings do given the stalled boundary near the I-35 sites. For now, we have pushed the onset of IFR ceilings back closer to sunrise, but we may need to change this once we see where the surface boundary is after the showers and thunderstorms dissipate. DRT will continue to see MVFR ceilings for most of the evening hours before IFR ceilings and patchy fog develops during the overnight hours. Scattered shower activity will most likely occur at some point overnight or tomorrow morning, but confidence was too low on the timing to put them into the TAFs at this time. Shower activity should ramp up tomorrow as overrunning continues over the boundary as it gradually dissipates and the moisture axis pushes further west. PREV DISCUSSION... /ISSUED 222 PM CDT Thu Sep 28 2017/ SHORT TERM (Tonight through Friday Night)... Ridging surface to aloft will persist over South Central Texas. Isentropic lift will gradually weaken as a shortwave moves to the northeast over the western states. PWS remain around 2 inches as a plume of moisture continues from south of Baja California and Bay of Campeche. Locally heavy rains are still possible. Have kept Flash Flood Watch for our southwestern areas through 7 PM CDT as that area has had copious amounts of rain the last few days and any additional heavier rains will quickly runoff. Otherwise, the threat for new flash flooding is quickly diminishing. However, with the PWs near 2 inches and some isentropic lift, POPs will remain high, especially Hill Country to Rio Grande Plains where isentropic lift is strongest. By Friday night, some drier air is drifting into South Central Texas from the northeast with rains mainly confined to the Rio Grande Plains and Edwards Plateau. LONG TERM (Saturday through Thursday)... Ridging continues over the weekend. Drier lower to mid level air filters to the southwest across South Central Texas with PWS falling to 1.5 inches as the moisture plume is only upper level. POPs end on Saturday. The lower to mid level ridge moves off to the east allowing southerly flow to return bringing an increase in moisture next week. Will maintain only low POPS as forcing mechanisms are weak. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 69 83 64 84 64 / 70 40 10 - 0 Austin Bergstrom Intl Airport 70 83 63 84 62 / 70 40 10 - 0 New Braunfels Muni Airport 70 82 65 84 63 / 70 40 10 - 0 Burnet Muni Airport 66 78 61 82 61 / 70 50 10 - 0 Del Rio Intl Airport 70 80 67 81 67 / 60 50 40 20 - Georgetown Muni Airport 68 82 63 84 61 / 70 40 10 - 0 Hondo Muni Airport 70 84 65 86 63 / 60 40 20 10 - San Marcos Muni Airport 70 83 64 84 62 / 70 40 10 - 0 La Grange - Fayette Regional 72 86 66 86 64 / 70 30 10 - - San Antonio Intl Airport 70 81 66 84 64 / 60 40 10 - 0 Stinson Muni Airport 72 83 67 85 66 / 60 40 20 10 - && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Mesoscale/Aviation...LH Synoptic/Grids...24 Public Service/Data Collection...YB
Area Forecast Discussion
National Weather Service Wilmington OH
937 PM EDT Thu Sep 28 2017 .SYNOPSIS... High pressure will keep dry weather over the region tonight. A disturbance crossing the Great Lakes will bring a chance of showers to northern locations on Friday. Strengthening high pressure is forecast to provide dry conditions on Saturday and Sunday. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Little reason to change the going forecast tonight, with a surface high nudging into the region from the west, and skies becoming almost completely clear across the entire forecast area. Based on 00Z RAP / 18Z NAM projections, and looking at the calm winds setting up, min temps were lowered slightly in the northern CWA. Valley fog was kept in across the southern portions of the CWA, where dewpoints are slightly higher. Previous discussion > Dry weather will persist tonight with high pressure centered to the west. Subsidence in a very dry airmass will result in clear skies. Calm winds will allow good radiational cooling, yielding low temperatures near dewpoints in the mid and upper 40s. Expect fog formation in river valleys as well. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... Clear skies will persist early Friday morning. A mid level short wave and associated surface trough crossing the Great Lakes will influence the weather mainly during Friday afternoon. All locations will see increasing clouds, and winds will gust close to 20 knots. Northern locations may see a few showers, especially north of Columbus, closer to the bulk of moisture and forcing. It appears that a few hundredths of an inch precip will be possible with this low end event. High pressure will be moving back in Friday night on a northwest mid level flow behind the disturbance. This will bring an end to shower chances, and the return of clear skies. Temperatures rising to the low to mid 70s will be a couple degrees above normal. && .LONG TERM /SATURDAY THROUGH THURSDAY/... On Saturday, surface high pressure will be located across the Great Lakes and the Ohio Valley. CAA in the wake of Friday`s system will bring the coolest highs during the extended, although plenty of sunshine will occur on Saturday. Highs on Saturday will range from the mid 60s north to near 70 south. The coolest lows of the period will occur Sunday morning with lows in the lower 40s northeast to the upper 40s along and south of the Ohio River. Models are still in agreement for the period Sunday into Monday. This period will feature surface high pressure moving east while a mid level ridge builds across the Ohio Valley. It will remain dry with a warm trending as return flow and a warming/modifying airmass takes place. Lower to mid 70s on Sunday will warm into the mid and upper 70s by Monday. Some disagreement continues among the long range models regarding upper level ridge and whether it will become suppressed. Suppression may bring a weak front into the region mid to late week. At this time, will keep the forecast dry. Temperatures Tuesday into Thursday should at least peak into the lower 80s which will be above normal for early October. Slightly warmer temperatures may be possible than this if the upcoming dry period and dry ground allow for easier heating of the earth`s surface which may result in a slight uptick in temperatures (versus what the raw 2 meter temperature models are forecasting). && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... Light northerly winds will become generally calm overnight, with some possible river valley fog (MVFR) at KLUK. Otherwise, VFR conditions are expected through the TAF period. The main story on Friday will be a cold frontal passage. This front will bring some cumulus clouds, as well as a wind shift over the course of the day -- SW to NNE. Winds will gust to around 15-20 knots at times, perhaps slightly less at the Cincinnati airports. There does appear to be a slight chance of a shower developing near the front, but too low a chance to mention in the TAFs. If this occurs, it would be most likely at KCMH/KLCK. OUTLOOK...No significant weather expected. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Coniglio NEAR TERM...Coniglio/Hatzos SHORT TERM...Coniglio LONG TERM...Hickman AVIATION...Hatzos