Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/17/16


Area Forecast Discussion
National Weather Service Dodge City KS
633 PM CDT FRI SEP 16 2016 ...Updated for Aviation... .SHORT TERM...(This evening through Saturday) Issued at 211 PM CDT Fri Sep 16 2016 A stubborn corridor of low stratus has persisted along the surface cold front boundary this morning into the mid afternoon. These clouds should improve along the central corridor, as the frontal boundary eventually shifts east later this afternoon and tonight while redeveloping farther east when the BL cools. The HRRR is still holding on to chances for convection along what appears to be a SE advancing radar fineline late this afternoon. The window for isolated storms is small however with the loss of differential heating. By Saturday, weak high pressure settle in behind the surface boundary which should be over western OK. That will mean generally light and variable winds in central KS with more of and easterly component for much of our area, and slightly warmer temperatures around 80 with more abundant insolation. .LONG TERM...(Saturday night through Friday) Issued at 211 PM CDT Fri Sep 16 2016 Models indicate a shortwave moving out of the Rockies into the Plains by late Saturday. The recent WRF runs are perhaps the most robust in terms of driving initial surface based colorado convection into western and even central Kansas Saturday night. It is likely the mid level instability will be more of a factor in sustaining storms this far east, as the surface dew points in the far west have decreased significantly. The rest of the extended period will generally be dry as a zonal flow and high pressure pattern takes shape for the central Plains. However the model blends suggest a return of thunderstorm chances late in the week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 629 PM CDT Fri Sep 16 2016 VFR conditions are forecast. As surface high pressure moves east, light winds will gradually become southeasterly after 15-17Z. Some mid level clouds increase also. && .PRELIMINARY POINT TEMPS/POPS... DDC 55 81 59 88 / 10 0 30 10 GCK 53 81 57 88 / 0 10 30 0 EHA 55 81 58 88 / 0 30 30 0 LBL 56 81 59 89 / 0 20 40 10 HYS 55 81 58 87 / 0 0 20 0 P28 61 83 61 87 / 20 0 20 10 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Russell LONG TERM...Russell AVIATION...Kruse
Area Forecast Discussion
National Weather Service Quad Cities IA IL
657 PM CDT FRI SEP 16 2016 ...AVIATION UPDATE... .SYNOPSIS... Issued at 307 PM CDT Fri Sep 16 2016 More breaks in the clouds helped early afternoon temperatures warm up into the lower 80s over much of the area. Areas behind a cold front, from Freeport to Iowa City and points to the northwest, were generally in the 70s. A broken line of showers and isolated thunderstorms continued to develop along the cold front, near and just west of the Mississippi River. && .SHORT TERM...(This Evening through Saturday) ISSUED AT 307 PM CDT Fri Sep 16 2016 The main forecast issued in the short term period are timing and coverage of showers/thunderstorms through tonight. Latest runs of the HRRR continue to model the current convective development near the Mississippi River quite well and gradually translate the broken line of showers and thunderstorms to the east of the river through the early evening. Some isolated small hail and gusty winds not out of the question with the strongest storms, but the threat for severe weather remains low, mainly due to relatively weak instability and deep layer shear. A few showers/isolated storms will be possible again later tonight, but have followed the 12z model trends in trimming back pops. Again, areas along and east of the Mississippi will be most favored for rain. Lingering cloud cover will influence lows tonight, with the northwest Wapsi Valley areas favored for the most clearing. These areas will likely dip into the mid 50s. On Saturday, drier air will filter into the region behind the cool front. Expect near normal highs from the low to mid 70s north, to near 80 degrees south. .LONG TERM...(Saturday Night through Friday) ISSUED AT 307 PM CDT Fri Sep 16 2016 A shift toward a more zonal upper level flow, with the main jet stream setting up along the U.S./Canadian border, will return summer-like weather for much of next week. This will lead to above to well above normal temperatures and seasonably high humidity levels. Weak frontal systems will bring potential for showers and thunderstorms Monday into Monday night, with a more likely setup for widespread rain late in the week. Sunday into Sunday night, the high shifts eastward with a breezy return flow warming temperatures into the upper 70s to lower 80s. Subsidence aloft and dry air should lead to mostly clear skies, but winds should stay up enough overnight to result in warmer night with mins from the upper 50s to lower 60s. Monday, a shortwave passing well to the north is shown drawing deeper moisture northward into the area, likely sufficient to support at least scattered showers and thunderstorms with the associated cold front in the afternoon and evening. Current timing would allow enhanced prefrontal warming to boost temperatures into the lower to mid 80s. High pressure that follows should allow mins to return to the 50s over much of the area. Tuesday will be between systems with slightly cooler temperatures. Convection is shown by the ECMWF and especially the GFS setting along a moisture convergence axis across the far north and NW late Tue night into Wed. The developing southerly winds will bring humidity back into the area with highs from the upper 70s north to possibly mid 80s in the south through Friday. Rain chances increase Thu and Fri as a the upper flow becomes more active from the southwest ahead of a developing trough over the Pacific NW. && .AVIATION...(For the 00Z TAFS through 00Z Saturday Evening) ISSUED AT 643 PM CDT Fri Sep 16 2016 Drier air working in behind a weak cold front will lead to mainly dry conditions through this TAF period. The lone exception is KBRL where light showers are possible this evening into early tonight as moisture streams up from the SW. Light southwest winds overnight should preclude dense fog formation, but will re- evaluate in next TAF update. Uttech && .HYDROLOGY... Issued at 127 PM CDT Fri Sep 16 2016 Adjustments were made this morning based on new forecasts and increasing confidence of flooding enhanced by the heavy rainfall that occurred last night over the upper reaches of the Cedar, Iowa and Wapsipinicon river basins. Along the Wapsipinicon River at DeWitt: New forecasts over the past couple runs have indicated a change from expected minor to now moderate flooding. With flood stage now looking increasingly more likely to be surpassed within 48 hours, have upgraded the watch to a warning for moderate flooding. Along the Iowa River: At Marengo, will be continuing the flood watch and monitor trends closely this afternoon as sharp rises continue there and at points upstream. If current trends continue, the watch may be upgraded to a warning for minor flooding this afternoon or this evening. Further downstream, adjusted forecasts taking into account release forecasts from Coralville no longer indicate flooding at Wapello or other sites downstream from Iowa City. including Wapello. Minor flooding that began last night along the Cedar River near Conesville continues this afternoon and the flood warning remains in effect. && .DVN Watches/Warnings/Advisories... IA...None. IL...None. MO...None. && $$ SYNOPSIS...RP Kinney SHORT TERM...RP Kinney LONG TERM...Sheets AVIATION...Uttech HYDROLOGY...Sheets
Area Forecast Discussion
National Weather Service Grand Forks ND
955 PM CDT FRI SEP 16 2016 .UPDATE... Issued at 955 PM CDT Fri Sep 16 2016 Upper level low was located over northwest MN. Upper low forecast to open up. Water vapor loop indicated one short wave was rotating around the upper low and was located over north central MN. Precipitation was decreasing in area and intensity with loss of heating and upper low moving out. Decreased pops with decreasing precip for overnight. Clearing was beginning over the far northwest zones. Decreased low temps for northwest zones tonight. UPDATE Issued at 659 PM CDT Fri Sep 16 2016 Tweaked pops, wind, sky, and qpf for tonight. No other changes at this update. && .SHORT TERM...(This evening through Saturday) Issued at 257 PM CDT Fri Sep 16 2016 The main forecast challenge will be the potential for any strong to severe thunderstorms across southeast ND into west central MN into the early evening. On the positive side, the SPC meso page shows sfc based lifted indices just slightly below zero across most of the FA. Some holes in the clouds have allowed temps to rise into the upper 60s across southeast ND and west central MN, with dew points in the upper 50s. This has resulted in sfc based CAPE values of 500-1000 J/kg. Water vapor imagery shows another wave moving toward southeast ND, rotating around the parent upper low over east central ND. It appears this area is being picked up somewhat by the non supercell tornado parameter on the SPC meso page, depicting a weak circle over southeast ND. On the negative side, 0-6km shear is weak, with the higher values moving into eastern MN. 0-3km VGP values around 0.1 are more over southwest MN, water vapor shows a more disjointed low, and the sfc pattern is weak. SPC maintains a marginal risk for severe weather over west central MN through early evening. The Mayville radar has shown an increase in popcorn showers and weak thunderstorms over the past hour. The HRRR continues to show this activity spreading into west central MN through the evening. So there is still a window from late afternoon into early evening where a few strong to severe storms are possible. Otherwise the pcpn will slowly decrease from west to east tonight into early Saturday. .LONG TERM...(Saturday night through Friday) Issued at 257 PM CDT Fri Sep 16 2016 A pleasant Saturday should be followed by similar weather on Sunday. Some cloud cover is likely to stroll from west to east along the International border by afternoon, but surface low pressure should remain far to the north over central Manitoba along with accompanying forcing vis a vis 500 mb short wave. So slight pops are featured only along far northern parts of the forecast area. Elsewhere a southwest breeze will boost the mercury well up into the 70s. On Monday this system will head farther to the north and east leaving the region with partly sunny skies and near seasonable temperatures. High pressure and zonal flow translates to another sunny and seasonal day Tuesday but on Wednesday there is a risk of some isentropically induced -RA/-SH north of a boundary lurking just south of the forecast area. By Thursday a closed "bowling ball" feature has a good shot of moving out of the northern high plains, affecting our region with perhaps an extended period of pcpn later Thursday on into Friday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 659 PM CDT Fri Sep 16 2016 Mostly MVFR cigs were located over the northwest third of the area or roughly northwest of a line from JMS to south of GFK to west of ROX. An isolated IFR cig was in the above area. VFR cigs were also moving into the far northwest zones or north and west of Cavalier ND. the south and east zones had VFR cigs. Satellite loop indicated some holes over the south and east zones. Expect the MVFR band to the north and west to shift south and east overnight. May see more IFR cigs as the night progresses in this band. The MVFR band should shift out of the area by Sat afternoon. && .FGF Watches/Warnings/Advisories... ND...None. MN...None. && $$ UPDATE...Hoppes SHORT TERM...Godon LONG TERM...WJB AVIATION...Hoppes
Area Forecast Discussion
National Weather Service Grand Rapids MI
738 PM EDT FRI SEP 16 2016 LATEST UPDATE... Aviation .SYNOPSIS... Issued at 328 PM EDT Fri Sep 16 2016 A frontal system moving through the area tonight through Saturday will bring some periods of showers and isolated storms through Saturday morning. Rain should diminish from Northwest to Southeast Saturday afternoon. There will be a small chance of a light rain shower Sunday afternoon as a weak wave of low pressure passes through. Drier weather will move back in across the area later on Sunday along with seasonable temperatures. && .SHORT TERM...(This evening through Sunday night) Issued at 328 PM EDT Fri Sep 16 2016 Our main focus is on the pcpn and thunder chcs and trends through Saturday afternoon. We are watching two areas of showers and a few storms that are poised to move through portions of the area through Saturday. The first one is the line that is currently developing across central and eastern Wisconsin this afternoon. This line is just ahead of the cold front, and is moving into a ribbon of 1000+ j/kg of sfc based CAPE. We expect this line to move in this evening and tend to weaken some as it moves through the area with the loss of diurnal heating. A few spotty showers could develop ahead of this with increasing moisture transport taking place in the mid levels. There may be a lull in the activity after the line this evening. We expect then that the area of showers and storms across KS and MO will make it`s way up toward the SE half of the CWFA late tonight and Sat morning. This pcpn will be drawn north toward the area as the RRQ of an upper jet develops and moves through the region. We expect most of the storm activity to remain south of the area with the srn portion of the llj staying south. There is enough instability that thunder will remain possible, but not likely. The cold front should then move through on Saturday with little fanfare. The atmosphere will not have much of a chance to destabilize before the front pushes through during the afternoon hours due to the lingering clouds and rain earlier. The majority of pcpn should be S and E of the CWFA by late afternoon. We have left the small chance of light rain showers in the fcst for Sun afternoon. We will see one more short wave move through during peak heating on Sun. There is not a lot of instability with just a couple hundred J/kg of CAPE. There is enough for a few showers though. These will end late Sun afternoon, leaving Sun night to be dry. .LONG TERM...(Monday through Friday) Issued at 328 PM EDT Fri Sep 16 2016 Guidance has been trending faster with the cold front next Monday, associated with the nrn stream shortwave racing across the Lake Superior region. Pops for showers and tstms are now warranted for Monday afternoon in western sections, and may need to be expanded for the entire area in later forecasts if the faster trend continues. The current timing supports best pops on Monday night, followed by dry weather Tuesday and Tuesday night as high pressure impacts the area. Things could turn active for the mid to late portion of next week as models show a quasi-stationary sfc frontal boundary possibly setting up over srn lwr MI. However confidence is low regarding the daily position of this front, and location of best PoPs/FGEN forcing, especially since previous runs had the front much farther north next Thursday and Friday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 732 PM EDT Fri Sep 16 2016 Scattered thunderstorms early this evening may produce brief reductions of visibility to IFR but otherwise cigs and visibility will generally hold up in VFR or MVFR with this activity. Overnight, a gradual reduction in cigs is strongly indicated by the RAP model RH at 975 mb. It seems by 04z-06z the cigs will begin dropping and by 09z there may be widespread IFR with LIFR possible especially at LAN and JXN. Rain along with a few thunderstorms moves in during the early to mid morning hours which will help the IFR linger well into the mid to late morning. && .MARINE... Issued at 328 PM EDT Fri Sep 16 2016 We will be leaving the Small Craft Advisory and Beach Hazards statements in effect with this forecast package. Conditions have been somewhat marginal thus far with a slightly offshore component to the wind. This will becoming a little more favorable this evening as winds are fcst to turn a little more SSW before winds come down later this evening. Winds will not settle down entirely, with winds up to around 20 knots at times through Sat night, and then increase again Sun night after a brief break. && .HYDROLOGY... Issued at 1158 AM EDT Fri Sep 16 2016 Rivers are running near to slightly above normal, but are stable and remain well within their banks. Moisture will stream northward out of the gulf late today into early Saturday, lending itself to developing showers and a few thunderstorms. Some of the rain may be locally heavy. Aerial averages should result in around one- quarter of an inch. Widely scattered storms are possible Saturday with lingering shower possible Sunday. Little additional precipitation is expected. There are no flooding concerns through the next several days with little to no signal of any bigger rain producers. && .GRR Watches/Warnings/Advisories... MI...Beach Hazards Statement until 5 AM EDT Saturday for MIZ037-043- 050. LM...Small Craft Advisory until 5 AM EDT Saturday for LMZ847>849. && $$ SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...Meade AVIATION...Hoving HYDROLOGY...JAM MARINE...NJJ
Area Forecast Discussion
National Weather Service Houston/Galveston TX
937 PM CDT Fri Sep 16 2016 .DISCUSSION... The weak surface low indicated on the water vapor imagery and also noted on METAR observations in the northwestern Gulf, is continuing to drift to the north. This system is keeping higher forecasted PoPs over the eastern offshore waters this evening and into the early morning. An isolated shower or thunderstorm cannot be ruled out along the coast, especially along the eastern half of the CWA. The 00z CRP and LCH soundings are still showing precipitable waters between 2.10 to 2.50 inches for tonight. Dewpoints are remaining in the upper 70s slightly inland within the coastal counties, but the best saturation still sits well to the east outside of our forecast area where the weak low is providing onshore flow. Short term guidance from both the RAP and HRRR are keeping the potential for a localized heavy downpour or isolated shower over the northern counties, until about 09Z this evening. Precipitation would be associated with a weak boundary that is currently sitting to the northwest that is slowly pushing into our area. This feature could help to provide some lift overnight as it moves to the southeast. Outflow is currently helping to drive convection along the boundary. If the outflow continues to develop as it moves into our northern counties, could be the mechanism helping to produce some of these isolated showers or thunderstorms. The boundary is currently along the I-20 corridor west of Dallas. Forecast soundings are showing decent saturation in the lower levels up to about 850mb, starting at about 03Z this evening and until tomorrow morning. Tweaked our temperatures for tonight a degree or two. After taking a preliminary look at model guidance, it appears as though guidance is looking to be slightly drier for the weekend. Wont make any wholesale changes just yet, but rain chances may need to be lowered, and temperatures may need to be raised a tad in the early morning forecast package. These changes would be due to the dry air that is filtering in ahead of the weak boundary moving in from the northwest, as well as subsidence pushing in along the backside of the low pressure system sitting off to our east. Hathaway && .PREV DISCUSSION... /ISSUED / AVIATION... The main aviation concerns for the 17/00Z TAFs center around SHRA near the central terminals early this evening, MVFR ceilings and visibilities developing early Saturday morning north of the Houston terminals, and SHRA potential near the terminals on Saturday. A few SHRA continue to fire along remnant outflow boundaries early this evening near CXO and east of IAH/HOU, but expect this activity to dissipate by mid-evening with loss of daytime heating. SHRA and TSRA associated with a weak surface low south of Cameron, LA (CWV) are expected to continue to drift inland away from Galveston this evening, allowing light easterly flow to become light and variable to light and southeasterly by Saturday morning with speeds 10 knots or less through the period. Latest HRRR ceiling progs show some IFR to MVFR ceilings developing as moisture wraps around the surface low as it moves inland tonight and may see brief category restrictions at UTS/CXO (possibly as far west as CLL) as a result. Similar to last night, patchy fog development near CXO/UTS is also possible and have included MVFR tempo groups as a result. Weak coastal convergence as southeast winds across the Gulf becomes established tonight should result in isolated SHRA developing near GLS early Saturday morning, with additional SHRA development spreading inland along a weak sea breeze late morning to early afternoon. Subsidence in the wake of the departing surface low/ parent upper level disturbance is expected to relegate greatest SHRA coverage to the coastal TAF sites on Saturday, but with convective temperatures near 90 for the Houston terminals may see a few showers farther north (IAH/SGR/CXO) during the afternoon. Huffman PREV DISCUSSION... /ISSUED / && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 76 92 76 92 75 / 20 30 10 20 10 Houston (IAH) 76 89 76 91 74 / 20 50 20 30 10 Galveston (GLS) 81 86 81 87 79 / 30 50 30 40 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ Discussion...08
Area Forecast Discussion
National Weather Service Wichita KS
853 PM CDT FRI SEP 16 2016 .UPDATE... Issued at 846 PM CDT Fri Sep 16 2016 Updated to clean up pops and to insert fog for south central and southeast KS. Showers have exited southeast KS and the storms west of Kingman/Harper have dissipated. Additional showers/storms are not expected overnight. Did go ahead and insert fog for areas generally along and southeast of the KS Turnpike. This will mainly be a radiational fog scenario as the low levels remain fairly moist with clouds clearing. && .SHORT TERM...(This evening through Monday night) Issued at 305 PM CDT Fri Sep 16 2016 Forecast challenge - Precipitation for this evening and tonight as the cold front pushes southeast. Convection that began off of an outflow boundary from the overnight activity ahead of the front has persisted in south central and southeast Kansas throughout the day. Given the worked over environment following this convection, it is not likely that there will be widespread redevelopment in most of south central as the front moves southeast. However, there was brief scattered development along the front in the early afternoon. In the clearing across southwest Kansas, scattered clouds have started to bubble along front which may move into south central Kansas. Right now reservation exists on how the evening will evolve. The HRRR and other models show persistent activity in southeast Kansas which will diminish after 0z with a complete exit by ~3z. Given the radar, it could be even sooner. Current thinking is the activity that would develop would be mainly heavy rain producers for the area which could lead to flooding. Ongoing convection falling onto the moist surface from the storms of last evening has caused flooding problems in southeast Kansas. Obviously any additional rainfall would exacerbate the problem. Chances of precip were held through the evening and overnight for now, yet anticipation in changes of the current forecast are likely. A ridge moves in for Saturday which will bring a pleasant day across the Plains. Outdoor activities are encouraged to flourish. There is a weak wave that will push through on Saturday night into early Sunday, but this is a very subtle feature especially closer to the surface. It is not out of the realm of possibility for scattered shower and thunderstorm activity after midnight along the KS/OK border. Slight chances were removed for the evening as the slight possibility appears to be later. .LONG TERM...(Tuesday through Friday) Issued at 305 PM CDT Fri Sep 16 2016 A ridge builds back in for the first of the week and will encompass a majority of the CONUS. The next trough will come from the Pacific Northwest on Wednesday. There is another subtle wave along the lee of the Rockies ahead of the main trough which will meander east for the latter part of the week. Models have definitely come into better agreement than yesterday with only slight timing differences; the Northern Plains anticipated position will cap off the work week. Current indications suggest this trough will be deepen more than the system from this week. More changes are on the way for the evolution of this system through model land. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 633 PM CDT Fri Sep 16 2016 Aviation concerns will be fog and low clouds tonight into Sat morning. Front currently extends from southeast Nebraska to between KDDC and KICT. While there isn`t much temp gradient with the front, there is a sharp dewpoint gradient, with moist low levels remaining over the eastern half of KS. Showers are departing se KS with the storms west of Pratt and Harper not expected to affect any of the tafs sites. With moist low levels remaining overnight, main concern will be developing fog and/or low clouds for all sites with the exception of KRSL-KGBD. At this time KICT and KCNU look to have the highest probability of seeing fog, especially if clouds clear out this evening. To gets things started will run with 4-6sm and MVFR cigs. May hit harder if 00z models runs continue to look favorable. && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 62 82 63 85 / 10 10 10 10 Hutchinson 60 82 61 85 / 10 10 10 10 Newton 61 81 61 84 / 10 10 10 10 ElDorado 63 82 61 84 / 10 10 10 10 Winfield-KWLD 64 83 63 86 / 10 20 20 10 Russell 54 81 59 87 / 10 10 10 10 Great Bend 54 82 59 87 / 10 10 10 10 Salina 59 82 60 86 / 10 10 10 10 McPherson 59 81 60 85 / 10 10 10 10 Coffeyville 65 84 62 86 / 50 20 20 20 Chanute 64 82 61 84 / 60 20 10 10 Iola 64 82 61 83 / 60 20 10 10 Parsons-KPPF 64 83 62 85 / 50 20 10 20 && .ICT Watches/Warnings/Advisories... None. && $$ UPDATE...RBL SYNOPSIS...VJP SHORT TERM...VJP LONG TERM...VJP AVIATION...RBL
Area Forecast Discussion
National Weather Service Lincoln IL
914 PM CDT FRI SEP 16 2016 .UPDATE... Issued at 910 PM CDT Fri Sep 16 2016 An elongated shortwave extending from central Illinois back to central Missouri will continue to create rain and isolated storms for the rest of the night. Areas east of the Illinois river will be the primary area affected by the wave, which looks to maintain some influence east of I-57 even up through mid-day on Saturday. Severe weather is not expected, but locally heavy rainfall could produce some ponding of water in low spots and poor drainage areas. Have updated PoPs and weather to cover the ongoing rains and expected progression of steady rains. Temps will be held warmer with persistent cloud cover and rains, along with mild dewpoints in the upper 60s to low 70s. Low temps may reach as low as the mid 60s NW of the IL river, with upper 60s E of I-57. Winds will remain SW through the night under the influence of WAA flows ahead of the upper trough in the Plains. Updated forecast info is already available. && .SHORT TERM...(This evening through Saturday) ISSUED AT 259 PM CDT Fri Sep 16 2016 Several disturbances ahead of a cold frontal boundary currently extending from Minnesota southward through Oklahoma will be the main features over the upcoming day. Presently, a small break between thunderstorm clusters over central and southeast IL looks on track for portions of the afternoon...then a disturbance currently over Missouri looks to spread additional thunderstorms into the area for the evening. latest HRRR model appears best on track with these features and have used this solution as a guide for tonight bringing back likely thunderstorms from around I-72 southward through the I- 70 corridor by 6 p.m. and 30-50 percent chance to the north. Scattered thunderstorms should persist through the night...then shifting slowly eastward through the day Saturday while tapering off from west to east. Lows tonight in the mid to upper 60s in the moist air mass ahead of the approaching cold front...then highs around 80 again Saturday as temperature contrast across the frontal boundary is minimal compared with the change in dewpoint...which should begin to drop into the upper 50s behind the front. .LONG TERM...(Saturday night through Friday) ISSUED AT 259 PM CDT Fri Sep 16 2016 The cold front should finally move through the rest of the state Saturday evening. With both the GFS and NAM hinting at additional precip developing along the front, keeping a chance of showers and storms in the forecast for the east and southeast parts of the CWA is a good forecast. Dry weather is then expected for the rest of the weekend and into the beginning of next week. However, with a somewhat zonal flow, another weather system will approach the area but will have limited moisture. The strongest part of this next system is expected to move into the Great Lakes region, but a trailing cold front will drop through the area Monday night. Will maintain a chance of showers and storms in the northern part of the CWA, mainly north of I-72. Another weather system is possible in the zonal flow for the last half of the week, but again, moisture will be limited. Also, models differ on placement and timing of the precip so will just keep the model blend of 20 pct chance of precip for Wed night through Friday. Zonal flow across the northern half of the US, from the weekend and through next week, will be conducive for an upper level high pressure to build into the southern US. This will bring warmer temps back into the area through most of the period. Expect highs during the afternoon above normal, in the lower to middle 80s; with above normal lows as well. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 700 PM CDT Fri Sep 16 2016 An extended period of forcing for precip will be affecting our forecast area overnight, as a 500 mb shortwave progresses NE across IL. The result will be steady rains and isolated thunderstorms at the terminal sites overnight. There may be periods of MVFR cloud and vis conditions during any heavier rains or storms. IFR conditions should be short-lived if they develop at all. It appears the back edge of the main wave of precip will reach SPI late tonight into Sat morning. That trend should provide decreasing rain and storm chances for at least the western terminals of SPI and PIA in the morning. Continued rain chances may linger through mid-day at BMI, DEC and CMI. VFR conditions and some clearing is expected later Sat afternoon. Winds will be prevail from the southwest through tomorrow morning, then shift westerly tomorrow afternoon. Wind speeds should prevail at 10kt or less. && .ILX Watches/Warnings/Advisories... NONE. && $$ UPDATE...Shimon SHORT TERM...Onton LONG TERM...Auten AVIATION...Shimon
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1041 PM EDT Fri Sep 16 2016 .UPDATE... Issued at 1041 PM EDT FRI SEP 16 2016 Current forecast is generally on track. Overall seeing a diminishing trend to shower and thunderstorm activity across the entire area. However, had to extend timing of pops a couple of hours in our south to account for lingering showers there. Still anticipating the possible redevelopment of activity late tonight in the north as shortwave energy tracks deeper into the Mid-West. Otherwise adjusted grids for hourly obs and freshened up the zones to remove evening wording. UPDATE Issued at 810 PM EDT FRI SEP 16 2016 Adjustments to the forecast package was mainly for shower and thunderstorm activity. Most of our activity this evening is diurnally driven and has begun to dissipate with sunset. However, shortwave approaching the Mid-West this evening is expected to keep activity going further north and west of our area and may impact our northernmost counties through the overnight. Based on current trends believe this approaching feature is even now helping to maintain ongoing activity along and west of I-75 and across our Blue Grass counties. Did bring grids in line with hourly trends. Also nudged grids later tonight towards latest CONSShort blended solution, which appears to have a better handle than usual on the current trends. && .SHORT TERM...(This evening through Saturday night) Issued at 311 PM EDT FRI SEP 16 2016 For the rest of this afternoon isolated showers and thunderstorms will occur, mainly across the southern and eastern part of the forecast area. Most areas will not see any rain this afternoon though. Until forcing increases with the approach of the upper level trough and surface cold front later in the weekend, convection should remain scattered at best. The models have not been handling the near term weather very well. This includes the HRRR, which last night was more aggressive with convection for today. As the day progressed the HRRR pulled back on the afternoon convection but has recently been showing more convection overnight, and even the GFS MOS is showing likely probabilties of rain in spots tonight. Not surprisingly the CR superblend came in with rather high probabilities tonight, but mainly in the northeast part of the forecast area, with low probability in the southwest. This at least makes sense with the best chance for showers in the southwest this evening and the northeast later tonight. With the model uncertainty in rain chances will adjust the superblend precipitation probability with the idea any convection will be spotty until Sunday and also considering neighboring WFO forecasts. .LONG TERM...(Sunday through Friday) Issued at 311 PM EDT FRI SEP 16 2016 The period will begin with a shortwave trough moving across the Great Lakes and Ohio Valley regions before pushing east of our region by Monday morning. Nice weather, incident with height rises, will ensue through midweek with upper level ridging building into southeastern CONUS. This ridging is progged to remain in place through the end of the period. At the surface, a cold front will push through East Kentucky from Sunday afternoon into Sunday night. High pressure will build in behind the front on Monday and remain in place through Tuesday morning. A quick-moving shortwave trough crossing through the Great Lakes will push a weak cold front into the Ohio valley Tuesday evening into Wednesday. This front is expected to wash out before reaching our area and therefore shouldn`t provide the area with any measurable precipitation. Another surface high builds into the region Wednesday and should remain in place through the work week. The only real chance for precipitation comes at the beginning of the period with the trough and cold frontal passage. This combination should produce showers and thunderstorms across the area Sunday through Sunday night, with the best chance on Sunday afternoon when there is plenty of instability for potential storms to tap into. Beyond this frontal passage, the weather should remain warm and dry with above normal temperatures, and slightly less humid conditions. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 810 PM EDT FRI SEP 16 2016 Expect VFR conditions will prevail through the TAF forecast period. Isolated to scattered showers and thunderstorms are beginning to die down now that the sun has set. However, approaching disturbance into the region appears to be helping to maintain activity in the far west and into our Blue Grass areas. Consequently will keep an eye on SYM in case some thunderstorm activity manages to roll into that area later this evening. For now went with VCSH through the overnight as thunderstorms have been isolated in coverage in that area. Winds look light through the overnight but will increase from the southwest Saturday ahead of an approaching cold front. Looking further ahead, the best chance for showers and thunderstorms still looks to be Sunday. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...RAY SHORT TERM...SBH LONG TERM...JVM AVIATION...SBH/RAY
Area Forecast Discussion
National Weather Service Memphis TN
857 PM CDT FRI SEP 16 2016 .DISCUSSION...Water Vapor Satellite/WSR-88D Vad Wind profiles this evening indicate a shortwave trough embedded within southwest flow aloft moving across portions of the Middle and Lower Mississippi Valleys this evening. This is resulting in showers and thunderstorms from East Central Missouri back through Northwest Arkansas and Eastern Oklahoma. Latest 00Z WRF and HRRR indicate shower and thunderstorms should begin to move into portions of Northeast Arkansas in the next 2-3 hours and across the remainder of the Mid-South overnight into Saturday morning. It appears the best chances for showers and thunderstorms will be mainly along and north of I-40 tonight and areawide on Saturday. Will make some adjustments to rain chances and any other elements as needed into tomorrow to account for short term trends. Updated grids will be available shortly. CJC && .PREV DISCUSSION... /issued 634 PM CDT FRI SEP 16 2016/ UPDATE... Updated to include the 00z aviation discussion. PREV DISCUSSION... /issued 320 PM CDT FRI SEP 16 2016/ DISCUSSION... An upper ridge continues to bring hot summer time temperatures to the Mid-South this afternoon. Temperatures are currently in the lower to mid 90s. A few showers and thunderstorms have developed mainly across northern portions of the Mid-South. The ridge will break down tonight which will allow a cold front to push into the Mid-South over the weekend. Numerous showers and thunderstorms have developed along old outflow boundaries ahead of the front across Missouri this afternoon. Latest HRRR, 4km NAM, and WRF models show this convection pushing into Northeast Arkansas later this evening. The convection will affect the Missouri Bootheel and Northwest Tennessee during the overnight hours. Old outflow boundaries from this convection will likely then trigger convection on Saturday afternoon. In fact, the WRF and 4km NAM show redevelopment occurring roughly from the Ohio River southward into Northeast Arkansas around 2-3 PM. However, convection could develop anywhere at anytime on Saturday. Will go with likely POPS across most of the CWA Saturday afternoon. Chances for showers and thunderstorms will linger into Saturday evening, but then expect a brief break early Sunday morning before a shortwave moves into the area setting off additional showers and thunderstorms. For now just have 30-40 POPS across the entire CWA as too hard to pinpoint best timing and location. Highs may stay in the mid to upper 80s over the weekend thanks to the convection and abundance of cloud cover. The shortwave will push east by Sunday evening as the cold front washes out over North Central Mississippi. Surface high pressure from the Ohio Valley will build into the area which will bring drier air into region. However, there will be little reprieve from the heat as the upper ridge gradually rebuilds over the region from Monday through the end of next week. Temperatures will return to the lower to mid 90s. KRM && .AVIATION... /00z TAFs/ Sustained convection has had a difficult time across the Mid-South this afternoon, but widespread showers and thunderstorms continue to the north and west of the CWA. This activity will sag slowly south and east overnight, gradually weakening with the loss of heating and the corresponding increase in convective inhibition. We do anticipate convection in the vicinity of KJBR by midnight, but the remaining forecast terminals are likely to remain dry much of the night. Scattered warm advection showers are expected to develop during the early morning hours in the warm sector, with additional convection forming in the vicinity of the approaching cold front. While drier air is expected to work in the KJBR area tomorrow afternoon, the rest of the area will remain warm and humid with scattered diurnal showers and thunderstorms. Winds will generally be light from the south overnight, but should veer southwesterly on Saturday. We should see northwest winds at KJBR by early afternoon as the surface boundary passes. Johnson && .MEG Watches/Warnings/Advisories... AR...None. MO...None. MS...None. TN...None. && $$
Area Forecast Discussion
National Weather Service Omaha/Valley NE
1045 PM CDT FRI SEP 16 2016 .SHORT TERM...(Tonight through Monday) Issued at 325 PM CDT FRI SEP 16 2016 Little in the way of impactful short term weather. Near surface soil moisture is high across the area due to heavy rainfall Thursday night into early Friday morning. RAP, SREF and HRRR and conditional LAMP guidance each hinting at some patchy ground fog, with visibilities perhaps dropping down into the 6 to 8 mile range. Decided to introduce a period of patchy fog from about 09 UTC through 13 UTC. Diurnal mixing will dissipate any ground fog that may form. Saturday night into early Sunday, there is a slight chance of nocturnal convection, as short wave feature enhances isentropic ascent 305-312K. Moisture appears limited to mid-levels so not confident that coverage will be too great. As such kept PoPs below slight chance. Temperatures will be seasonal through the weekend, and forecast guidance looked reasonable and accepted consensus. By late in the short range, temperatures will be on the rise, as mid-level ridging builds over the central U.S. Downslope component to wind will allow max temperatures to jump 5-10 degrees from Sunday to Monday. .LONG TERM...(Monday night through Friday) Issued at 325 PM CDT FRI SEP 16 2016 Upper flow remains predominately zonal across northern plains, with large scale H5 ridging entrenched over southern plains. H5 heights suggests temperatures will remain slightly above normal through Wednesday. Deterministic and ensemble models are consistent in moving a cold front across the region Wednesday evening into Thursday. Best dynamic forcing will be well to the north of the forecast area, and question how far south front will push as it encounters mid- level ridging across the southern plains. As such, some sort of boundary linger across the area providing a focus for convection. Thermodynamic/diabatic effects will be enough to generate some convection and consensus solution of low chance PoPs entering amd remaining in the forecast from Wednesday night into Friday looks reasonable. && .AVIATION...(06Z TAFS for KOFK...KLNK and KOMA.) Issued at 1045 PM CDT FRI SEP 16 2016 VFR conditions are expected through the period. && .OAX Watches/Warnings/Advisories... NE...None. IA...None. && $$ SHORT TERM...Fortin LONG TERM...Fortin AVIATION...Boustead
Area Forecast Discussion
National Weather Service Blacksburg VA
911 PM EDT Fri Sep 16 2016 .SYNOPSIS... High pressure will keep a wedge in place over our area overnight. By Saturday, high pressure will still be located in the area with Julia stuck offshore of South Carolina. A cold front enters the Ohio and Mid Mississippi Valley Sunday, moving through the mid- Atlantic states Monday. && .NEAR TERM /THROUGH SATURDAY/... As of 845 PM EDT Friday... Shallow wedge remains in place tonight with low clouds having already filled back in along the Blue Ridge after loss of heating. However less low deck over far southern sections where the evening GSO raob showed a much drier boundary layer under a bit steeper inversion aloft. Also some breaks showing up across the Mountain Empire region along the periphery of the cool pool, and where earlier spotty convection developed near the instability gradient. Therefore still cant rule out an isolated shower far western ridges through midnight given leftover weak convergence/instability just west of the area, but since iffy wont include. Otherwise expecting low clouds to become more widespread again overnight as trapped low level moisture spreads out, while eventually lowering enough to result in spotty fog/drizzle espcly eastern slopes of the Blue Ridge by daybreak. Thus beefed up clouds from the Blue Ridge east and included more fog and patchy drizzle late. Also lowered temps a degree or two in spots, although only expecting slow falls, mainly back into the 60s, given cloudiness and higher dewpoints overnight. Previous discussion as of 345 PM EDT Friday... A dirty wedge continues to dominate the region as low clouds were seen by most today. Some areas did see clearing over the course of the day, but will more than likely cloud over again this evening as little change to the pattern is expected through Saturday afternoon. At that point, some clearing can be expected and temperatures should rebound a bit through the mountains. Current HRRR shows that the best chances for precip for the duration of the day exist over the Grayson Highlands and the Northwest Mountains of NC, however rainfall amounts look to be very minimal. More widespread showery activity should be anticipated on Saturday ahead of an upper level trof approaching the region. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... As of 300 PM EDT Friday... The weather pattern remains blocked with high pressure over the western Atlantic. This blocking pattern will keep Tropical Storm Julia hovering off the southeast coast and a cold front sitting over the midwest Saturday night. A northern stream upper level trough will begin to push the cold front slowly across the Ohio Valley Sunday, then over the Mid Atlantic States Sunday night into Monday. Prefrontal showers may clip the Greenbrier Valley Saturday night into Sunday afternoon, but the bulk of the widespread light rain will move across with the front Sunday night into Monday. Not much forcing with the passage of this front, but enough lift may squeeze out a half of an inch /0.50/ of rain across southeastern West Virginia and around quarter of an inch /0.25/ over the southwestern Virginia and northwest North Carolina mountains. The flow becomes westerly fairly quickly as the front tracks across the mountains Monday morning to limit rainfall to under a quarter of an inch east of the Blue Ridge. A secondary line of showers may develop over the piedmont Monday afternoon. At this time, models have this line developing well east of Blacksburg CWA and in the coastal piedmont of Virginia. Showers will taper off from west to east Monday afternoon as the upper level trough pivots over the region. Temperatures will warm above seasonal levels until the frontal passage Monday. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 330 PM EDT Friday... A cold front slides across the region Monday night, but clouds will likely remains as theta-e ridging lingers over the area. The upper level trough is expected to become a closed low over the southeastern states as it begins to interact with Tropical Storm Julia. An upper level ridge will build east from the Gulf States Wednesday and center itself over the Carolinas by next weekend. This ridge could take Julia westward across Florida and into the Gulf of Mexico. For the immediate area, this ridge will bring several days of warmer than normal temperatures and little chances for rain. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... As of 645 PM EDT Friday... Variable cigs will continue into this evening with VFR to high end MVFR across the western and eastern perimeters with MVFR central sections closer to the Blue Ridge where the wedge remains deeper. Isolated showers/storms could also affect KBLF in the next hour or two before loss of heating so may need to include a vicinity mention there. Otherwise plenty of uncertainty exists with the fluctuation of cloud height and coverage this evening before the wedge starts to deepen again overnight. This scenario as suggested by most short term models and forecast soundings should cause cigs to once again lower through MVFR to IFR most spots overnight including the addition of some patchy fog and/or drizzle late. Wedge should erode a bit quicker on Saturday as the flow turns more southerly allowing cigs to improve to VFR from west to east into the afternoon. Only exception may again be along the Blue Ridge and points northeast to around KLYH where sub-VFR cigs may hang on longer. Therefore delayed improvement to VFR there until early/mid afternoon. Appears any showers well ahead of the front will remain confined to the far west including the KBLF-KLWB vicinity, but since late in the valid TAF period wont include any mention for now. Extended aviation discussion... Cold front edges east but remains well west of the mountains Saturday night. Appears best chance of seeing pockets of sub- VFR Saturday night will remain along the KBLF-KLWB corridor with showers just ahead of the front. Otherwise appears mostly VFR cigs Saturday night with some patchy fog around as moisture increases. Sunday-Monday still looks unsettled as a cold front sags slowly east across the region. Expect threat of showers and storms with possible sub-VFR cigs/vsbys espcly later Sunday into Sunday night mountains, and across the east later Sunday night into Monday. Anticipating a return to more widespread VFR Tuesday into Wednesday with weak high pressure building in behind the front through midweek. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...RCS NEAR TERM...JH/JR SHORT TERM...RCS LONG TERM...RCS AVIATION...AMS/JH/JR
Area Forecast Discussion
National Weather Service SAN ANGELO TX
654 PM CDT FRI SEP 16 2016 .AVIATION... /00Z TAFS/ Scattered showers and thunderstorms are approaching the KABI terminal early this evening and will affect the terminal between 00Z and 03Z. KSJT may see some SHRA/TS move into the area between 02Z and 05Z. Expect possible wind gusts to 45 KT, along with temporary MVFR ceilings/visibilities. Confidence is lower across the southern terminals regarding convection and will not mention at this time. VFR conditions expected on Saturday, with scattered afternoon convection developing mainly across the KABI and KSJT terminals. && .PREV DISCUSSION... /issued 314 PM CDT FRI SEP 16 2016/ SHORT TERM... (Tonight and Saturday) The NAM and GFS models both close an upper low off the southern California/northern Baja coast overnight while an upper high builds over southern Texas. This will place the forecast area in a roughly zonal upper flow aloft. Both the HRRR and the NAM and to some degree the GFS bring disturbances in the flow aloft over the mid and upper portions of the CWA this evening. Will therefore place the best chance of rainfall over the Big Country with lesser POPs over the mid-section of the CWA. As the upper high over southern Texas builds further northward and over the southern portions of the CWA during the day on Saturday,the best chance of rainfall will be relegated to the northern half of the forecast area. Will not see much change in the highs and lows over the area with morning lows in the upper 60s to around 70 and the afternoon highs around the 90 degree mark. 15 LONG TERM... (Saturday night through next Friday) Models have continued to trend drier for the long term forecast. There is a weak shortwave currently moving southeast through the ID/MT area this afternoon that is expected to make its way into the southern plains by Saturday night. As this trough swings through, an MCS may develop across the Caprock area and move southeast into the northern half of our CWA late Saturday night into Sunday morning. Will go ahead and keep slight chance to chance PoPs in the forecast from Saturday night into Sunday for this reason. After Sunday, the ridge builds and strengthens from the Southern Plains east into the Carolinas. This will return us to more summer-like conditions, keeping our high temperatures 5 to 10 degrees warmer than normal, and precipitation chances low. 20 && .PRELIMINARY POINT TEMPS/POPS... Abilene 70 89 69 93 / 50 30 20 20 San Angelo 70 92 69 94 / 30 20 10 10 Junction 70 93 70 95 / 10 20 10 10 Brownwood 71 91 70 93 / 40 30 10 20 Sweetwater 68 88 69 92 / 60 30 20 20 Ozona 71 92 69 93 / 20 20 10 10 && .SJT Watches/Warnings/Advisories... None. && $$ 99/99/24
Area Forecast Discussion
National Weather Service Albuquerque NM
350 AM MDT SAT SEP 17 2016 .SYNOPSIS... A heightened threat of severe thunderstorms is expected for one more day across much of eastern New Mexico today before a drier and much less active pattern develops Sunday and Monday. Much of western New Mexico should remain storm free through the weekend. A closed low aloft developing southward just offshore of far southern California today will remain nearly stationary through Monday before opening up and lifting northeast early next week. After the drying trend to start the new week, this system will pull moisture northward again and enhance thunderstorm chances from Tuesday through Wednesday. A much stronger low pressure system could deliver significant changes for late next week. && .DISCUSSION... Cluster of showers and thunderstorms in the vicinity of Los Alamos and Santa Fe with isolated activity now beginning to develop/expand farther east across the northeast highlands per latest model trends. Latest RAP objective meso analyses suggest a fairly broad region of modest upper level divergence just north of a 250-300mb jet axis that continues to cut across southern New Mexico. That coupled with lift ahead of positively tilted shortwave trough crossing the central Rockies should provide favorable environment through remainder of the morning for isolated to scattered SHRA/TSRA. Made some minor adjustments to PoP/wx for NC/NE areas. Elsewhere, areas of stratus have slowly expanded along/east of the central mountain chain but have yet to see signs of convective precip development for EC/SE zones. Appears the focus will be just east of the NM/TX line but 06z NAM continues bullish trend thru 18z. Otherwise, main wx concern after 18z will be the potential for severe storms across the east once again, especially the southeast. Boundary layer flow veering to SW and surface dew points in the 40s across the northeast may preclude significant, sustained threat there. But backed low level flow looks to maintain mid 50 to near 60 dew points east of the Pecos River and south of the Caprock region beneath fast westerlies aloft where severe potential should be greatest -- to include much of eastern Lincoln, Chaves, De Baca, Curry and Roosevelt counties. That being said, the latest NAM and GFS not overly impressive with QPF despite impressive instability parameters. So coverage may be more isolated across our CWA with better coverage with east/southward extent. The west should again remain quiet save for the the activity this morning and perhaps isolated activity over the higher terrain NC/NW. Sunday and Monday trending noticeably drier/less active areawide as 50mb heights rise and drier air across the far west and Four Corners advances eastward . Closed low aloft developing southward just offshore of far southern California today will remain nearly stationary through Monday before opening up and lifting northeast early next week. Could get nice bump in moisture across the west later Tuesday into Wednesday. All eyes then shift to what could be an especially dynamic/impactful stretch of weather late next week but significant model differences keeping uncertainty quite high. The GFS continues to show an anomalously deep/large upper low taking aim on the southern Rockies while the 00Z ECMWF has trended deeper than its previous run but weaker than the GFS and thus remains more progressive. We often mention a secondary severe weather season this time of year, and the pattern Thursday-Saturday fits that conceptual model quite well even if the more progressive ECMWF were to verify. Stay tuned... kj && .FIRE WEATHER... A dry west to northwest flow aloft will result in a dry day for all but the far eastern plains today. Isolated thunderstorms will be possible across the eastern plains this afternoon before drier air from the west wins out all areas Sunday. Sunday continues to look like the first day since sometime back in July with no thunderstorms/lightning strikes anywhere in the state. Minimum relative humidity values are forecast to drop below 15 percent across all but the southeast plains Sunday and Monday afternoons. Four Corners high is forecast to build northwestward late-day Sunday into Monday, allowing temperatures to warm above seasonal averages both days. Weather prediction models agree that the upper high will get pushed east of New Mexico Tuesday. The upper high gets shoved east as an upper level low drops into the PACNW, sending a weak upper low off of the southern California coast northeastward. Monsoon moisture will increase across western New Mexico in southwest flow aloft head of the California low. This moisture and the associated showers and thunderstorms spread east across the remainder of the forecast area Wednesday and continue through at least Friday. Model solutions diverge next weekend. GFS wants to deepen the upper trough/closed low as it drops southeastward into the Great Basin. ECMWF is farther north until the trough moves east of the Rockies, then it splits the low with the southern portion deepening over the southern plains. These differences would result in major sensible weather differences across NM next weekend. GFSensemble mean is not too far removed from the operational GFS but the same is true for the operational ECMWF and its ensemble mean. 33 && .AVIATION... 06Z TAF CYCLE VFR conditions prevail and are forecast to persist at KFMN, KGUP, KAEG, KABQ and KSAF. An east canyon/gap wind is peaking between 15-20kts sustained at KABQ currently, but will be trending down over the next several hours. MVFR cigs are forecast to develop overnight at KLVS and KROW, and possibly at KTCC. Improvement Saturday morning at KROW should be slow. KROW may be impacted by storms late Saturday afternoon moving southeast off of the higher terrain to the west. 11 && .PRELIMINARY POINT TEMPS/POPS... Farmington...................... 81 43 83 43 / 0 0 0 0 Dulce........................... 77 32 78 35 / 5 0 0 0 Cuba............................ 74 40 77 43 / 5 0 0 0 Gallup.......................... 79 33 82 35 / 0 0 0 5 El Morro........................ 76 34 78 39 / 0 0 0 5 Grants.......................... 80 37 81 41 / 0 0 0 5 Quemado......................... 78 42 80 46 / 0 0 5 5 Glenwood........................ 84 52 86 55 / 0 0 5 5 Chama........................... 70 33 71 36 / 10 5 0 0 Los Alamos...................... 74 46 77 48 / 20 5 0 0 Pecos........................... 74 44 77 47 / 30 10 0 0 Cerro/Questa.................... 72 38 75 42 / 20 10 0 0 Red River....................... 61 32 65 34 / 30 10 0 0 Angel Fire...................... 68 28 71 30 / 30 10 0 0 Taos............................ 74 36 77 39 / 20 10 0 0 Mora............................ 70 40 75 44 / 40 10 0 0 Espanola........................ 79 48 82 50 / 20 10 0 0 Santa Fe........................ 74 46 77 49 / 20 10 0 0 Santa Fe Airport................ 78 45 81 47 / 20 10 0 0 Albuquerque Foothills........... 81 52 82 52 / 5 5 0 0 Albuquerque Heights............. 83 54 84 55 / 5 5 0 0 Albuquerque Valley.............. 85 51 86 51 / 5 5 0 0 Albuquerque West Mesa........... 84 53 85 53 / 5 0 0 0 Los Lunas....................... 85 52 86 53 / 5 5 0 0 Rio Rancho...................... 84 51 85 53 / 5 5 0 0 Socorro......................... 87 54 87 55 / 5 5 5 0 Sandia Park/Cedar Crest......... 76 46 78 48 / 10 5 0 0 Tijeras......................... 80 45 81 51 / 10 5 0 0 Moriarty/Estancia............... 77 42 79 47 / 20 10 0 0 Clines Corners.................. 76 44 78 47 / 20 10 0 0 Gran Quivira.................... 78 48 80 51 / 10 10 5 0 Carrizozo....................... 82 54 84 56 / 10 10 10 5 Ruidoso......................... 75 48 78 52 / 10 20 20 5 Capulin......................... 74 44 80 47 / 40 30 0 0 Raton........................... 77 42 82 46 / 40 30 0 0 Springer........................ 77 42 83 45 / 40 20 0 0 Las Vegas....................... 74 44 80 47 / 30 10 0 0 Clayton......................... 79 53 85 53 / 40 40 0 0 Roy............................. 75 47 83 50 / 40 30 0 0 Conchas......................... 82 57 88 57 / 40 20 0 0 Santa Rosa...................... 82 54 87 55 / 30 20 0 0 Tucumcari....................... 84 58 90 57 / 40 30 0 0 Clovis.......................... 81 58 87 56 / 40 30 5 5 Portales........................ 80 59 87 57 / 30 30 5 5 Fort Sumner..................... 82 59 88 57 / 30 20 0 0 Roswell......................... 85 60 90 59 / 30 30 10 5 Picacho......................... 80 55 85 56 / 30 20 10 10 Elk............................. 77 52 80 54 / 20 20 10 10 && .ABQ WATCHES/WARNINGS/ADVISORIES... None. && $$ 41
Area Forecast Discussion
National Weather Service Buffalo NY
530 AM EDT SAT SEP 17 2016 .SYNOPSIS... Showers and a few thunderstorms will bring wet weather ahead of a slow moving cold front that will cross the region this weekend. While the bulk of the rain is expected later today into tonight, showers will linger into Sunday before drying out Monday. Another cool front will swing through Tuesday, bringing a slight chance for showers before high pressure brings more dry weather for the middle of the coming week. Today will be the warmest day of the period with 80s in some locations today and 60s tonight. Temperatures will cool somewhat behind the front, but will still run near to slightly above average through much of the coming week. && .NEAR TERM /THROUGH TONIGHT/... A look at regional MRMS radar mosaic this morning illustrates the broad synoptic picture quite nicely. An initial widely scattered band of showers can be found along a warm front arcing from NE Ohio, across Southern Ontario and across Georgian Bay into a surface low centered near the Boundary Waters of Minnesota. A second, much more consolidated and impressive band of rainfall can be found stretching from the Middle Mississippi valley across Indiana and into Lower Michigan. This second area of rainfall is occurring ahead of a cold frontal boundary in an area of favorable synoptic lift with falling heights and plenty of DPVA aloft courtesy of an upstream upper level low and associated troughing over the upper Midwest. A robust SSW- NNE oriented LLJ of 30-40kts at 850mb is advecting a healthy supply of GOMEX moisture into the aforementioned pre-frontal zone, with pwats exceeding 1.75 inches. The aforementioned low pressure system will gradually track east- northeast into Quebec over the next 24 hours. As for this morning...a cluster of showers and thunderstorms over NE Ohio is gradually moving up the Lake Erie shoreline towards PA/NY at the moment and bears watching...however it is progged to fall apart by HRRR guidance. While we may still see scattered shower activity across portions of Western and North-Central New York this morning as the associated warm frontal boundary lifts across the area, the bulk of the rainfall will likely hold off until later this afternoon and the arrival of the pre-frontal trough, low-level jet, and the main slug of moisture. This band of rainfall will then gradually makes its way across the forecast area overnight tonight. Given the favorable dynamics, ample supply of GOMEX moisture, with anomalously high pwats in excess of 1.75 inches, and the roughly front-parallel flow in the upper levels, resulting slow forward motion, the stage is set for the forecast area to receive some much needed rainfall. Ensemble guidance suggests widespread accumulations in excess of an inch are possible over the next 24 hours, with localized amounts exceeding 2 inches across the higher terrain east of the lakes through tonight. In addition to the abundant rainfall, there will be at least a marginal threat for severe weather, as would be expected given the 35-40kt 925-850mb jet that will be arriving over Western New York late this afternoon into this evening. While instability will not be overly impressive, with forecast CAPEs in the neighborhood of 500 j/kg, the abundant shear will be supportive of bowing segments that may produce localized wind damage. With plenty of warm and moist air advecting across the region ahead of the cold front, it will be yet another warm September day across the forecast area. The addition of gusty southerly winds and associated downsloping will push the mercury even higher across the Genesee valley and Lake Ontario plains, where the mercury will break the 80 degree mark, with upper 70s expected elsewhere. The warm and moist airmass will linger through tonight, with lows only expected to fall into the mid to upper 60s across most areas. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... Low pressure will track from eastern Ontario province on Sunday into central Quebec Sunday night with a trailing cold front slowly shifting east across western into central New York. A parent mid level trough axis will shift east from the Midwest states to western New York by Monday morning. A plume of seasonably high 1.25-1.50in Pwats should be found ahead of the cold front suggesting plenty of moisture available for shower potential although NAM BUFKIT point soundings are showing a weak 700mb cap and limited instability of 500-1000 j/kg CAPE. This weak cap and modest instability will limit any thunderstorm threat to just a few rumbles of thunder within better organized cells Sunday focused toward the southern Finger Lakes region into south-central NY. The lowest POPs have been placed over the Niagara Frontier. Temperatures will continue to run above mid-Sept normals with highs ranging from the low 70s across the higher terrain to upper 70s along the southern Lake Ontario shoreline and Genesee Valley. Dewpoints in the mid 60s will add an elevated humidity factor as well. Chances of showers will linger into Sunday along the slow moving front. Low temps will also remain very mild only slipping back into upper 50s/low 60s Sunday night. On Monday the mid-level trough will cross New York pushing the front and associated deeper synoptic moisture east into New England. Incoming dry air and surface high pressure briefly building in behind the departing front will help clear skies and provide mainly dry weather with just a slight chance of a shower east of Lake Ontario. Another frontal system will cross the central lakes Monday night to just west of Buffalo. This second front is what will finally knock back dewpoint temps into the more comfortable range of 50s F for midweek. Highs Monday will run in the mid to upper 70s for most with a few isolated 80 degree readings possible toward the Finger Lakes. Another mild night with lows only slipping back to between the mid 50s inland to mid 60s toward the lake shores. && .LONG TERM /TUESDAY THROUGH FRIDAY/... A near zonal flow along the Canadian border during this period will mark the northern extent of a sub tropical ridge that will initially be centered over the Southern Plains. As we progress deeper into the week...the ridge will drift east and amplify over the Ohio Valley. This whole scenario will guarantee that our temperatures will average above normal throughout this period. In fact...the mercury will be roughly 10 deg F above 30 year norms with highs generally in the mid to upper 70s. These readings will be more typical of mid August. On a day to day basis... A weak cold front will cross our region on Tuesday. The aforementioned sub tropical ridge will block any GOMEX moisture from making its way int our region though...so the moisture starved frontal passage will only be accompanied by sparse shower activity. Have kept slight chance POPs for most with low chance pops focused east of Lake Ontario. High pressure over the upper Mid West Tuesday night will then push east across the Lower Great Lakes for Wednesday. This will supply our region with a period of fine weather with light winds and comfortable temperatures. As the surface high moves off the Mid Atlantic Coast...another weak cold front will settle to the south across our region Thursday and Friday. Again...the front will be moisture challenged and with little frontogentic forcing expected...the opportunity for showers again looks limited. Will continue to use low chance pops for the bulk of the region. && .AVIATION /10Z SATURDAY THROUGH WEDNESDAY/... High clouds continue to overspread the region early this morning in advance of a low pressure system currently centered along the Minnesota/Ontario border. A warm front lifting north across the region ahead of this system will bring a low chance of showers this morning, however the bulk of any shower/thunderstorm activity will likely hold off until this afternoon, mainly after 18Z, when the main zone of lift and moisture associated with the system is expected to move across the forecast area. Expect mainly VFR conditions with periods of MVFR in heavier showers this afternoon. In addition, there will be enough instability and synoptic forcing to support at least a chance of thunderstorms this afternoon and evening as the cold front associated with this system nears the area. In addition to the MVFR conditions, expect gusty SW winds to develop from 15Z onwards with gusts of 20-30kts possible this afternoon. With increasing moisture across the area and potential widespread rainfall, expect cigs to lower tonight to MVFR, with IFR cigs developing across higher terrain of the Southern Tier and the Tug Hill Plateau after 03Z. Outlook... Sunday...Conditions returning to mainly VFR with showers diminishing. Monday...VFR. Tuesday...Mainly VFR with a chance of showers. Wednesday...VFR. && .MARINE... A warm front lifting across the region bringing freshening southerly winds is building waves on the lakes this morning, however most of this wave action is confined to Canadian waters. The one exception is in eastern Lake Ontario, near the entrance to the Saint Lawrence River, where waves are expected to build in excess of 4 feet today. A small craft advisory for this area and accompanying Beach Hazard Statement for Jefferson County have been issued through this afternoon. Otherwise, look for a brief lull in winds/waves across eastern Lake Ontario late this afternoon into this evening as flow veers to the WSW. The break will be short-lived however as the WSW winds freshen and gradually veer more westerly tonight as a slow-moving cold front crosses the lakes. Another round of small craft advisories, this time including eastern Lake Erie as well, have been issued to cover this. Winds and waves will gradually diminish through the day on Sunday with more tranquil conditions on Monday as high pressure transits the area. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...Beach Hazards Statement until 2 PM EDT this afternoon for NYZ007. MARINE...Small Craft Advisory from 8 PM this evening to 5 AM EDT Sunday for LEZ020-040-041. Small Craft Advisory until 2 PM EDT this afternoon for LOZ045. Small Craft Advisory from 8 PM this evening to 8 AM EDT Sunday for LOZ045. && $$ SYNOPSIS...WOOD NEAR TERM...WOOD SHORT TERM...SMITH LONG TERM...RSH/WOOD AVIATION...WOOD MARINE...WOOD
Area Forecast Discussion
National Weather Service Charleston SC
407 AM EDT Sat Sep 17 2016 .SYNOPSIS... The region will remain situated between Tropical Depression Julia meandering off the Southeast U.S. coast and inland high pressure through early next week. A cold front will advance into the region by the middle of next week, stalling just south of the region as high pressure builds from the north. && .NEAR TERM /THROUGH TODAY/... An inland wedge of high pressure will hold firm today as Tropical Depression Julia continues to meander well offshore and weaken. Broad, synoptic-scale subsidence and extensive mid-level dry air induced by a strong southwest-northeast oriented upper level ridge extending from from the eastern Gulf of Mexico, across the Southeast U.S coast to offshore the the Mid-Atlantic states will support another dry and warm day. Lowered pops slightly from the previous forecast, only showing 20% pops for parts of the Charleston Tri-county area where both the RAP and H3R show a few showers developing mid-late afternoon. K-indices are progged to remain in the lower teens so the Troposphere still remains too dry to support tstm development. Highs will range from around 90 across interior Southeast Georgia to the upper 80s elsewhere away from the coast. Highs may be held down just a bit north of I-26 corridor where low-stratus advecting in from the northeast may limit thermal rises after sunrise. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... Tonight: High pressure wedging will remain in tact as Julia transitions to a remnant low well offshore. Temperatures will drop steadily after sunset as any lingering cumulus away from the coast should dissipate with the loss of insolation. Any isolated showers that can spawn in the northeast low-level flow look to remain confined to the coastal waters where boundary layer moisture will be the most plentiful. Conditions favor another round of stratus either developing over the area or propagating in from the northeast after midnight. Most of the statistical guidance show some degree of a stratus deck prior to sunrise, which coincide with the low 1000 hPa condensation pressure deficits noted in the 17/00z NAM12. The boundary layer will decouple inland, so some of the stratus could translate to some fog. Lows will range from the upper 60s well inland to the upper 70s at the beaches. Sunday through Tuesday: Surface high pressure covering the eastern United States and ridging aloft will cause the remnants of Julia to further weaken offshore. Higher PWATs will remain further offshore as the high pressure inland wins out. Though, isolated showers associated with the weakening system may work across the coastal waters and possibly reach the South Carolina beaches. Heights aloft will begin to fall Sunday night as broad troughing shifts eastward from the Great Plains. The remnants of Julia will deteriorate rapidly into a wave as the upper level wind speeds increase during this time. A cold front will approach the area Monday, pushing the remnants of Julia out to sea. Increasing moisture ahead of the front combined with increased instability justify chance POPs by Monday. This should be the best day for thunderstorm potential, especially in the afternoon. However, given the low amplitude of the trough and the modest WAA ahead of the front, the severe threat remains low. The front will cross through our area Monday night and stay to our south on Tuesday. High pressure building into our area from the north will bring drier conditions. Temps will be near to a few degrees above normal thanks to the ridge overhead and increasing WAA early next week. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... The cold front will be far to our south Tuesday night while high pressure to the north builds into our area and brings drier conditions. The high will dominate our weather through the end of next week. Showers should remain mostly confined to the coastal waters. Though, it`s possible some could move onshore, especially towards the end of this time period. Hence, we have periods featuring slight chance POPs for the coastal counties while further inland is dry. Temperatures will generally be near normal. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... KCHS: Short term models show another round of low-stratus potentially impacting the terminal prior to sunrise. The bulk of this looks to remain north in the KMNI-KMKS-KGGE vicinity, but may drop into the terminal by 11-12z. Will carry a tempo group for low-end MVFR cigs for now. VFR otherwise. KSAV: VFR. Could see a very brief chance for MVFR cigs right around sunrise, but current thinking most of the low-stratus will remain to the north. Extended Aviation Outlook: Showers may bring brief flight restrictions Sunday and Monday, especially in the afternoon. && .MARINE... Today: The pressure gradient will remain pinched today between inland high pressure and Tropical Depression Julia. The tightest gradient will remain confined to the Charleston County and Georgia offshore waters where NE winds 15-20g25 kt will persist. Expect slightly lower winds elsewhere. Long period easterly swells from Julia and wind wave will support combined seas 2-4 ft nearshore waters from Edisto Beach south to the Georgia coast with 4-6 ft over the Charleston (AMZ350) and Georgia offshore waters (AMZ374). A Small Craft Advisory will remain in force for AMZ350-374 mainly for seas and frequent gusts to 25 kt. Tonight: Conditions will finally begin to improve as Julia continues to wind down and inland high pressure holds form. The tighter gradient looks to shift farther offshore which will allow winds to gradually diminish. Seas will diminish a bit as well, but 6 ft seas will linger over the Charleston County and Georgia offshore waters through this evening. Sunday through Wednesday: Julia is forecasted to weaken off the Southeast U.S. coast on Sunday. Our waters will remain on the western periphery of the weakening circulation, which will allow northeast winds to prevail. The remnants of Julia will be pushed further offshore on Monday as a cold front approaches the waters. The front will pass through our area Monday night, moving south of our area on Tuesday. High pressure to our north will then build into our area, generating a return to northeast winds. Seas are expected to subside to 1-2 ft by Monday night. Rip currents: Long period 10-11 second easterly swell from Julia combined with astronomical influences from the current full moon will keep the rip risk at moderate today. An elevated risk will continue through Sunday as the swell from Julie slowly fades. && .TIDES/COASTAL FLOODING... Early morning extratropical storm surge guidance once again brings both the Charleston Harbor and Fort Pulaski tide gages to shallow coastal flooding thresholds with this morning`s high tide cycle, but just barely. Since there is still a slight offshore component with the low-level wind field and surface pressures are running 1-2 hPa higher than 24 hours ago, will once again hold off on the issuance a Coastal Flood Advisory and monitor trends. The need for an advisory will be reevaluated during the next several hours as high tide approaches. A Coastal Flood Advisory will likely be needed for all or portions of the coast with the higher, evening high tide cycle. Shallow salt water flooding will be possible once again Saturday, mainly during the evening along the South Carolina coast. As we move further from the full moon and the northeast flow decreases as Julia weakens Sunday, the threat for shallow coastal flooding should subside. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...Small Craft Advisory until 11 PM EDT this evening for AMZ350- 374. && $$ ST/MS
Area Forecast Discussion
National Weather Service State College PA
548 AM EDT SAT SEP 17 2016 .SYNOPSIS... A moist southerly flow ahead of a slow moving cold front will bring an increasing chance for showers across the western half of the state later this morning and this afternoon. The chance for showers and scattered thunderstorms will increase elsewhere across central the central mountains and Susq Valley late today into Sunday. Rainfall totals by late Sunday will likely be near one inch in many locations. A few places could see slightly heavier amounts. Improving conditions with decreasing humidity will occur Monday through at least early Thursday as a large area of high pressure builds in from the Midwest. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Areas of strato cu were noted across the South-Central Mtns...and especially over the Lower Susq Valley where skies were bkn-ovc early today as a result of a southerly 925-850 mb flow. Partly cloudy skies in the form of cirrus were observed between the route 219 and I-99/RT 220 corridors. Conditions will stay dry through 12z and beyond over most of the CWA. Low temps around sunrise will vary from around 50F over the western Poconos, with mid to upper 50s over the northern and western mtns. Readings over portions of the Middle and Lower Susq Valley will be in the 60-65 degree range as a result of the bkn- ovc strato cu deck. Moisture will continue to increase today ahead of slow moving frontal system approaching from the Ohio Valley overnight and tomorrow. The chance for showers will be on the increase during the late morning/early afternoon hours west of the I-99 corridor...with locations just east of the I-99/RT220 corridor likely staying dry until 19-20Z per the last several runs of the HRRR that depict a lead band of convection (showers and scattered TSRA) forming along a prefrontal trough. The deterministic NAM and SREF are most aggressive in bringing showers east today, while the bulk of other operational guidance (HRRR and GEFS) are slower and suggests more in the way of just scattered showers and isolated thunderstorms in the increasingly humid and unstable airmass. A pair of weak/fast moving upper jetlets will lift NE from eastern Ohio and cross far NW PA...bringing the most frequent/heaviest showers and embedded tsra to that region this afternoon/evening. SPC has roughly the NW 1/3 of the CWA in a Marginal Risk for SVR TSRA this afternoon and evening...thanks to a 30-40kt southerly 925-850 mb jet with decent streamline convergence just to the west of this wind max. Further east...gradually weaker llvl winds and slight diffluence/anticyclonic curvature to the flow should minimize the areal coverage and intensity of the shra and tsra. The showers through 21z will be confined mainly to the western half of the state. 925-850 mb diffluent flow and speed divergence will help to minimize the areal coverage rainfall amounts from showers/isolated TSRA. Highs this afternoon will be a few degrees warmer than Friday... ranging from the mid 70s north to the lower 80s in the southeast. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/... Cfront will gradually push east across the region after midnight and slow as several weak waves of low pressure at the sfc and aloft ripple newd along it. POPs through 12Z Sunday will be likely to categorical across the NW half of the CWA...with 35 to 60 POPs near and to the SE of Interstate 81. Low temps early Sunday will be mild and in the 60s. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Little change in the high probability for frequent showers and scattered TSRA Sunday and Sunday night across Central and Sern PA as the cfront edges slowly sewrd. some drying and lower pops should spread into the NW mtns Sunday afternoon/evening...but will maintain chc pops there through around midnight. Afterward, there are no other notable times in the long-term period when it is worth drawing POPs over 20. Even then only over the far northern tier as weak fronts try penetrate the force field over central PA. Low pressure rolls through northern Ontario and Quebec early in the period. The associated cold front checks in but does not check out of PA as the boundary layer and upper flow become nearly parallel. PW does not quite reach 2 inches, but the constant southerly flow around the high pressure off the coast will yield a long period of deep moisture. The front finally pushes through Sunday night and early Monday. This is a bit of a slow-down from previous forecasts, but probably to be expected with an already- sluggish front and no real kicker of an upper trough. A minor surface wave tries to form over the central Appalachians and track over MD/SE PA right as the front finally looks to move out. So, the heaviest rain could come to the southeastern zones on Sunday night and early Monday. The first part of the new week looks dry, with a surface high overhead. A very weak and moisture-starved front moves along in the progressive westerly flow and could make a passing shower across the far north on Tues. But, again, it holds almost no hope of rainfall for anyone, as the Gulf is cut off and drought does beget drought. A warm front and perhaps light precip will set up just to our north later in the week as we go from temps "only" 0 to 5F above normal back to temps some 10F warmer than normal by mid-week. There might even be a run at 90F in the far southeast later in the week. There is a hint in many of the models that the front just to our north may try to inch southward in backdoor fashion on Friday. However, we will keep day7 dry for now. Temps through the period will remain 5 to 10F above normals for maxes and mins - and mins might be 10+ above normal during the weekend with all the clouds and moisture. && .AVIATION /09Z SATURDAY THROUGH WEDNESDAY/... A return of sub VFR is likely again overnight into Saturday as moisture begins to increase ahead of an approaching cold front. SERN terminals are likely to remain VFR longest as showery rains take their time progressing eastward. Outlook... Sun...Scattered impacts as a slow moving frontal system moves through the region. Mon-Wed...no sig wx. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert NEAR TERM...Lambert SHORT TERM...Lambert LONG TERM...Dangelo/Lambert AVIATION...Ross/Gartner
Area Forecast Discussion
National Weather Service Hastings NE
416 AM CDT SAT SEP 17 2016 .SHORT TERM...(Today and tonight) Issued at 351 AM CDT Sat Sep 17 2016 Today will be absolutely beautiful with light winds, mostly clear skies, and highs in the upper 70s across south central Nebraska to near 80 over north central Kansas. A sfc high will track east across Kansas resulting in the light wind, which will shift from westerly to southerly as we head through the day. The primary forecast concern and point of uncertainty will surround the chance of thunderstorms this evening. Moisture will be very limited with dewpoints currently in the 40s to around 50 and these will climb only slightly by this evening into the the lower 50s. A subtle hardly noticeable vort max/upper trough will slide east off the high plains this evening. The 07Z HRRR is the most aggressive with developing showers and thunderstorms across eastern Colorado by late afternoon, which then push east into our western zones predominately after 7 pm. Several WRF models also indicate that this high plains convection could make it at least into our western zones this evening. Therefore, have added a chance of thunderstorms to the forecast for this evening leaning towards the lower superblend POPs. There will be at least a marginal severe weather threat off to our west late this afternoon, but given our feeble instability (SBCAPE 500-1000 J/KG) and the late hour of arrival as we lose diurnal heating it seems that any storms should be weakening as they make it into our western forecast zones. Given decent deep layer shear of 30 kts and at least some initial limited instability, can not completely rule out an initial strong storm or two in our far west from Gothenburg, down to Beaver City, and south into Plainville, KS. Weakening thunderstorms will likely die out before midnight and currently seem unlikely to make it any further east than Highway 281, but this should be watched and updated in future forecasts. .LONG TERM...(Sunday through Friday) Issued at 351 AM CDT Sat Sep 17 2016 Dry conditions remain in the forecast to start of the long term period on Sunday, and are expected to continue into the first part of the upcoming work week. By Sunday morning, models are in pretty good agreement showing zonal to low amplitude northwesterly flow having developed in the upper levels, in the wake of a departing shortwave trough axis. Overall, not expecting a lot of change in the overall pattern as we go through Sunday and even into Monday/Tuesday. Upper level flow remains zonal, with the CWA set up between high pressure building over the southern Plains and a disturbance sliding east across Canada. Models not showing much in the way of waves affecting our area, thus the forecast remaining dry. At the surface, west-southwesterly winds are expected to be in place during the day on Sunday, with high pressure over much of the southeastern CONUS and a frontal boundary working its way in from the west. This boundary looks to push through the area late Sunday night into Monday, but not much in the way of impact is expected outside of a switch to more northwesterly winds and lower dewpoints. High pressure behind this boundary builds into the area for later Monday/Monday night, before sliding off to the east, allowing for southerly return flow for Tuesday. Forecast highs for Sun-Tues remain in the 80s. Looking to the mid-later portions of the week, there is more uncertainty in the forecast, as precipitation chances make a return. The upper level pattern across the Central Plains transitions to southwesterly flow by Wednesday morning, as the ridge axis associated with that southern Plains high gets pushed east of the area by low pressure/troughing moving onto the West Coast. A more organized upper level low pressure system is expected to start working its way east into the Rockies through the Wed-Fri period, but confidence isn`t the highest. There are notable differences between models with the timing/track of this system, with the 00Z ECMWF quicker/further north than the 00Z GFS. Hard to go higher than 20-30% chances at this point, lot of details with any lead shortwaves are yet to be determined. && .AVIATION...(For the 06Z KGRI/KEAR TAFS through 06Z Saturday night) Issued at 1242 AM CDT Sat Sep 17 2016 VFR conditions will persist throughout the TAF valid period. The wind will be rather light and shift from westerly to southerly through the period as an area of sfc high pressure slides off to the east. Low level wind shear will increase tonight (Saturday night), but appears to be below the threshold where we would include it in the TAF. && .GID Watches/Warnings/Advisories... NE...None. KS...None. && $$ SHORT TERM...Wesely LONG TERM...ADP AVIATION...Wesely
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
515 AM EDT Sat Sep 17 2016 .SYNOPSIS... Tropical system Julia will linger just off the southeast coast over the weekend then slowly dissipate, keeping the heavier rainfall mainly over the coastal waters. A cold front will approach the Western Carolinas Sunday, and move through the area early Monday. Drier high pressure returns in its wake. && .NEAR TERM /THROUGH TONIGHT/... As of 230 AM...precip had yet to develop near the Blue Ridge, so that has been eliminated for the time being, and we shall see if upslope flow is strong enough to force anything in the pre-dawn hours. Also in question is the development of low clouds and fog from the east toward the Piedmont. Satellite imagery shows an area of low stratus over the coastal plain moving slowly west, but it has a way to go before reaching the fcst area. Temp trends look good for now. The next 24 hours look fairly quiet around the western Carolinas. Although the upper ridge axis has moved well to our east and we come under an increasing SW flow aloft with the broad upper trof located over the Plains, our sensible weather will change very little from yesterday. We remain under a weak sfc ridge in-between the circulation of what is left of Julia off the Southeast Coast and a cold front to the west. If anything, the boundary layer is expected to be a bit drier this afternoon which will put an even greater limit on deep convection over the mtns. Think it will be isolated at best and close to the TN line. High temps should continue to run about five degrees above normal. Most of the tonight period should also be quiet, although the approach of a short wave from the west and the development of some weak upper divergence suggest that precip ahead of the cold front could encroach from the west toward daybreak over the mtns. Precip chances start to ramp up before dawn over the far W, otherwise most places should be dry. Min temps will also remain seasonally mild. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... As of 215 AM Saturday: A broad trough will push across the Mississippi Valley on Sunday, as a high-amplitude upper ridge sits over the western Atlantic. As the associated surface low pushes toward Newfoundland, a cold front will trail it into the southeast CONUS. The consensus of latest guidance brings this front through our CWFA early Monday. Drier high pressure will build overhead in its wake, though the impact on temperatures looks minimal. Currently it appears we will remain in the prefrontal environment through most if not all of the daytime hours Sunday. Winds are expected to veer to west late in the day over the mountains after peak heating. Unseasonably warm and humid conditions will be felt at the surface. Lapse rates are not remarkably strong in light of the incumbent ridge, but modestly unstable conditions should develop. PoPs are allowed to increase diurnally, with the mountains most likely to see precip before sunset. These chances spread east and generally peak overnight as base of trough passes and winds shift. It is expected that the drier and more subsident air will settle over the NW half of the CWFA early enough on Monday to permit a dry fcst there; over the Piedmont some instability is expected to develop again, so a schc to low chc pop will be maintained. Downsloping winds and actually slightly higher thicknesses suggest Monday may be slightly warmer than Sunday at some locations, though dewpoints will be a few degrees lower. Skies should clear out Monday night though mins are expected to remain several degrees above climo. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 130 AM Sat: As high pressure moves out of the northern Plains, another weak cold front will push into the Ohio Valley Tuesday, though global models suggest this will wash out before it reaches the southern Appalachians. Low-level flow veers from northerly to easterly over the CWFA through late week as that high migrates to the East Coast. Warm and mostly sunny conditions will continue in this pattern, with maritime moisture being shunted south of the area. Temps will remain several degrees above normal, but dewpoints will be more comfortable than they have been of late. && .AVIATION /09Z SATURDAY THROUGH WEDNESDAY/... At KCLT...VFR for the time being, but there are big questions about the development of an IFR cloud deck to the east. Some of the model guidance, in particular the LAMP, paints a very pessimistic picture of widespread MVFR/IFR ceilings developing by daybreak, which has yet to happen. The upslope flow does not look strong enough to force that much low cloud development. Instead, the RUC idea that a low cloud deck will move in from the east looks more plausible, which agrees with satellite imagery at issuance time. Problem is, the RUC brings the stratus and fog within sight of the air field before its westward progress stops. The current motion of the low clouds seen on satellite imagery has the leading edge reaching the air field between 12Z and 13Z. Will bring in the low clouds at 12Z but keep them sct for the time being, and await further developments. The low clouds should scatter quickly by mid morning. Wind will begin ENE and should switch to ESE in the mid afternoon, then go light and variable after sunset. Elsewhere...a low cloud deck near the Blue Ridge may result in some VFR ceilings. Over the mtns, though, expect cloud bases to be lower and in the MVFR range. Valley fog was already developing, so going with a temporary IFR at KAVL is not a big stretch. This could easily end up VLIFR by daybreak. The clouds should scatter by mid morning. After that, VFR at all locations. Chances of showers this afternoon are too small to mention. Outlook: A cold front is expected to cross the area late in the weekend, bringing small chances for showers, mainly to western portions of the terminal forecast area on Sunday. Much drier air will filter into the region early next week, which is expected to usher in an extended period of VFR. Confidence Table... 09-15Z 15-21Z 21-03Z 03-06Z KCLT High 94% High 100% High 100% High 100% KGSP High 87% High 96% High 100% High 100% KAVL Med 77% High 83% High 100% High 100% KHKY High 81% High 92% High 100% High 100% KGMU High 85% Med 79% High 100% High 100% KAND Med 75% High 92% High 100% High 100% The percentage reflects the number of guidance members agreeing with the scheduled TAF issuance flight rule category. Complete hourly experimental aviation forecast consistency tables and ensemble forecasts are available at the following link: www.weather.gov/gsp/aviation && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...Wimberley NEAR TERM...PM SHORT TERM...Wimberley LONG TERM...Wimberley AVIATION...PM
Area Forecast Discussion
National Weather Service Lincoln IL
326 AM CDT SAT SEP 17 2016 .SHORT TERM...(Today and tonight) ISSUED AT 326 AM CDT Sat Sep 17 2016 A band of showers and thunderstorms should be exiting east-central and southeast Illinois early this morning, with the balance of the forecast area likely to be dry through the period. The showers/storms are associated with an upper-level disturbance streaking across the area, along with an associated surface boundary. While the model guidance suggests a dry day once the current precipitation pushes east of the area, still a little concerned that we may see a "surprise" shower/storm through tonight. An upper-level low and associated troffing will still lie to our west for much of the day, along with a surface cold front. These features are progged to be weakening with time as they track east, but until they are completely east of the area the threat of an isolated shower/storm can`t be completely discounted. That being said, considering the lack of precipitation and cloud cover upstream, and dryness of the forecast soundings, do not plan to include PoPs beyond the current morning rainfall. Notably cooler and less humid air will filter into the region tonight behind the cold front, with low temperatures tonight expected to fall into the 50s over most of the forecast area. && .LONG TERM...(Sunday through Friday) ISSUED AT 326 AM CDT Sat Sep 17 2016 Behind the exiting system, the forecast remains dry through the remainder of the weekend, with mild temperatures. In the overnight hours on Sunday, a narrow ridge at the sfc slips eastward and more southerly winds at the sfc begin a short period of WAA, and slightly warmer temps for Monday. ILX sits on the edge of a more zonal flow across the northern tier of the country. A wave rippling through that zonal flow across southern Canada drags a front through the region later Monday/Monday pm. A bit of a wind shift with the front and some minimal convergence at the sfc...warrants some low pops, mainly for Mon night. Watching the timing for Mon afternoon, particularly in the north. Mostly zonal flow just to the north maintains the mild weather through mid week with warm temperatures and quiet weather. Models portraying a pattern shift for the latter half of the week as a large upper low digs out over the Pac NW and amplifies the flow over the CONUS, putting the Midwest in increasingly southwesterly flow. Typically, this would result in a more active pattern with short waves rippling through the larger scale trof. However, the GFS and ECMWF on the 00z runs are having some differences in handling the western low. General consensus breaks off part of the wave and isolates it in the southern high plains...but major difference in the strength of the remaining trof...as well as the location and potential cyclogenesis of the sfc system associated with the cut off h5 low over the southern US. Extended remains conservative at this point, there is a lot of variability in the solutions for the forecast going into next weekend. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1150 PM CDT Fri Sep 16 2016 An extended period of forcing for precip will be affecting our forecast area for the rest of the overnight, as a 500 mb shortwave progresses NE across IL. The result will be steady rains and isolated thunderstorms at the eastern terminal sites. HRRR and upstream observations are pointing toward MVFR clouds developing by 09z-10z, with IFR clouds near and shortly after sunrise tomorrow. It appears the back edge of the main wave of precip will reach SPI and PIA before sunrise, with the other terminal sites seeing rain tapering off by mid to late morning. Due to the upper trough still affecting central IL, a few showers could develop for CMI and DEC into early afternoon. However, most areas should see dry conditions after 18z. VFR conditions and some clearing is expected Sat afternoon from west to east. Winds will be prevail from the southwest through tomorrow morning, then shift westerly tomorrow afternoon. Wind speeds should prevail at 10kt or less. && .ILX Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Bak LONG TERM...HJS AVIATION...Shimon
Area Forecast Discussion
National Weather Service North Platte NE
359 AM CDT SAT SEP 17 2016 .SHORT TERM...(Today and tonight) Issued at 355 AM CDT Sat Sep 17 2016 The main concerns in the short term period centers around rain showers/thunderstorms chances and the potential for strong and/or severe thunderstorms. At the present time satellite imagery shows clear skies and no significant weather occurring across the forecast area. Warmer conditions are expected today, with highs forecast in the lower 80s, about three to eight degrees above normal. Above normal lows are then expected overnight, mid 40s in the far western portion of the forecast area to low to mid 50s in north central NE. Weak 500 hPa height rises will be occurring at the start of the period over western and north central NE as a broad 500 hPa trough will be over the MN Arrowhead Region and far Upper Great Lakes. The upper level trough will deamplify over the next 24 hours as it lifts eastward into the extreme eastern portion of Ontario. In the meantime, a short wave trough is anticipated to move east across south central WY to southwest NE to north central KS by late this evening. This disturbance is expected to provide weak large scale ascent and support convective development as mid-level lapse rates steepen over northeast CO and the NE Panhandle into western NE this afternoon and evening. Meanwhile, broad surface high pressure currently over the Central Plains will move eastward today and a weak lee side trough will develop and deepen near the Front Range. Current thinking is that convective development will be focused in this trough. Wherein modest instability and sufficient moisture will combine with 0-6 km bulk shear generally about 20-35 kts that will be conducive for organized multicells. Of which, moisture looks to be the primary limiting factor and this could be attributable to the amount of moisture being returned northward into the forecast area today. Development is expected to move from northeast CO into the forecast area and/or occur in southwest NE early-mid evening with isolated to scattered coverage expected. Hi-res deterministic guidance, HRRR and flavors of WRF, were in decent agreement at the present time with forecast development shown 21-00Z today. Confidence in development is further increased based on SPC SSEO output from the 00Z cycle today wherein a strong signal appears present over southwest NE and northeast CO for convection. The main risks will be strong winds and hail. Of note, the latest SPC Day 1 Outlook has the southwest quad of the forecast area in a marginal risk area, which seems appropriate if storms can develop given aforementioned vertical wind shear. Ultimately, a strong/severe storm or two could be possible today, and cannot be ruled out. Any development is expected to taper off/diminish in the late evening or move southeast out of the area. After which, quiet conditions are expected. .LONG TERM...(Sunday through Friday) Issued at 355 AM CDT Sat Sep 17 2016 Generally upper level zonal flow overhead with a broad ridge across the southern plains to begin the week. Thermal ridge Sunday across the area with highs into the 80s. A weak cold front will enter the picture on Monday. Models in disagreement on timing the front through the southern part of the CWA. Expect the northern part of the CWA to see about 5 degrees or so drop in temps from Sunday, however less confidence for the area along and south of I80. Forecast is conservative across the south and will continue temps only a couple of degrees cooler, but would not be surprised to see highs a degree or two warmer due to compressional heating ahead of the front. Little moisture to work with and temps aloft stay fairly warm for mid September and expect the passage of the front to be dry with only some passing clouds. Thermal ridge quickly rebuilds for Tuesday with temps expected to go back up. Next upper level trough and sfc frontal passage is expected Wed. Ahead of the front southerly winds will usher in some sfc moisture which will aid in keeping lows very mild Wed morning, only falling into the mid 50s and lower 60s. The return of sfc moisture will result in a chance for precip with the passage of the front, mainly in the east on Wed. The trough will continue to push to the north with another trough to dig to the west. The ridge will get shoved east with more SW flow aloft. This will return some upper level moisture and bring a better chance precip with several disturbances. Pops are low at this time as model differences exist with waves. Expect at least more mid and high clouds. Pending cloud cover which could keep temps lower during the day, mos guidance still keeps afternoon highs fairly close to seasonal averages or warmer. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1057 PM CDT Fri Sep 16 2016 Skies will mainly be clear across western and north central Nebraska through midday Saturday. By Saturday afternoon, some mid level clouds around 10000 FT AGL will begin to move into southwestern and portions of western Nebraska. Some broken CIGS of 10000 FT AGL are possible at the KLBF terminal from 21z Saturday through 02z Sunday. Isolated thunderstorms are possible across far southwestern Nebraska during the late afternoon and early evening hours on Saturday. However, at this time, activity is expected to remain south and southwest of the KLBF terminal. && .LBF Watches/Warnings/Advisories... None. && $$ SHORT TERM...ET LONG TERM...Masek AVIATION...Buttler
Area Forecast Discussion
National Weather Service Lubbock TX
303 AM CDT SAT SEP 17 2016 .SHORT TERM... Thunderstorms have started to develop along a weak surface boundary/front across our southwestern zones. The boundary is hardly discernible using surface obs as winds are light and vary variable, but the boundary does show up on radar. This convective development coincides with an upper level jet streak moving into the FA as shown by WV imagery and a LLJ that has developed over the past few hours. This activity is being pushed east northeastward by the mid and upper level flow. The only model to pick up on this activity well is the 00Z run of the TTU-WRF and keeps this activity going till after sunrise before dissipating across our northeastern counties. The 06Z run of the HRRR also shows this activity, but has it developed further north than it currently is and pushes the convection southeastward instead of northeastward and dissipated the convection fairly quickly. Given the persistent and even strengthening LLJ, it can be believed that convection could be sustained at least for the next several hours. Now for the big question: what will happen from later this morning into tonight? Models have each given their thoughts on the matter, and each thought is different from the other models. Given that the higher res mesoscale models have performed the best recently, they will be weighted more heavily in the forecast. An upper level shortwave currently over northeastern UT/southwestern WY should develop a lee trof by the late morning in CO, during which time convection is progged to develop over the higher terrain of NM. The terrain induced convection has the potential to push eastward into the FA possibly merging with convection along the lee trof to form a QLCS. The QLCS may push into our northern zones of the FA later this evening , but current guidance keeps it northward in the TX and OK Panhandles. For now chance PoPs for this evening will remain unchanged due to the uncertainty of where the QLCS will go. Aldrich .LONG TERM... The long term will serve up warm and dry weather as a change in the upper pattern takes place early in the period. Upper level ridging will build over the region Sunday with the center over or near the region through Tuesday. Wednesday will see the ridge shift to the east as an upper trough develops over the western CONUS. It is looking more and more like energy from this trough will remain well west of the forecast area, a trend noted in the last several model runs. Really cannot pick out a period where thunderstorm chances would be high enough to include in the forecast, and will thus remove mention through Friday. Have again trended temperatures toward MOS for Monday and Tuesday, slightly higher than the model blend. Otherwise, the blend looks fine. && .LUB Watches/Warnings/Advisories... None. && $$ 51/07
Area Forecast Discussion
National Weather Service Paducah KY
344 AM CDT SAT SEP 17 2016 .SHORT TERM...(Today through Monday night) Issued at 344 AM CDT Sat Sep 17 2016 Current radar trends indicate showers and isolated thunderstorms moving across the region faster than previously forecast. The latest HRRR and ECMWF seem to have a decent handle on the timing. This lends itself to a quicker end to precip across the region, with far western portions of the PAH forecast area precipitation free by mid day, and all but far eastern portions dry by late afternoon. Adjusted precipitation chances to reflect this trend, and removed precipitation chances completely for late tonight and Sunday. Temperatures will cool down just a little behind the cold front to near seasonal readings. High pressure will shift across our region for Sunday night into Monday night. This will keep our region dry, and winds will shift back to the south. Temperatures will warm back up to above seasonal readings with highs Monday in the middle to upper 80s, and lows Monday night middle to upper 60s. .LONG TERM...(Tuesday through Friday) Issued at 344 AM CDT Sat Sep 17 2016 Above average confidence through most of the period, then average to below average at the very end due to model inconsistencies. Very little to discuss and very few changes synoptically in the long term period, especially if the ECMWF pans out. High pressure at the surface and ridging aloft is forecast through the long term period producing dry, warm, and humid conditions. On Friday the GFS weakens and suppresses the upper ridge southward allowing a back door cold front to sag into the far northern and northeastern sections of our CWA and cranks out a bit of QPF in the process. During the same time frame the ECMWF keeps the ridge stronger and keeps all frontal boundaries and precipitation chances well to our north. Will go with the more consistent ECMWF solution for now and keep it dry every period. Temperatures will remain at or above normal through the period. && .AVIATION... Issued at 1156 PM CDT Fri Sep 16 2016 Decaying MCS moving through southeast Missouri will continue to weaken/dissipate as it moves slowly eastward overnight. TS has really dropped off, and would be very unlucky to have even a stray strike at KCGI or KPAH overnight. Not sure if there will be any solid precipitation left as it tries to get to KEVV and KOWB toward morning. Latest HRRR guidance develops fresh band of convection near KEVV around 15Z and pushes it eastward through KOWB through midday. Hit this TS with a TEMPO group at both sites. Not sure if this will develop back toward KPAH. A weak surface trough/front will try to push through the area Saturday, but ahead of it multiple outflow boundaries will muddle wind fields overnight. Figure a southwest wind will develop most locations in the morning, but not sure if it will ever really shift to the northwest. KCGI is the best bet for a tangible wind shift. There is a strong signal for MVFR ceilings to develop in the morning and persist for most of the day, if not into the evening. Cannot even rule out IFR ceilings for awhile in the morning, especially at KCGI. && .PAH Watches/Warnings/Advisories... IL...None. MO...None. IN...None. KY...None. && $$ SHORT TERM...RST LONG TERM...JP AVIATION...DRS
Area Forecast Discussion
National Weather Service Pueblo CO
401 AM MDT SAT SEP 17 2016 .SHORT TERM...(Today and tonight) Issued at 400 AM MDT Sat Sep 17 2016 ...Threat of Severe Storms for the Southeast Plains Today... Main concern today will be the threat of svr wx over the SE Plains this afternoon. Will see CAPE of 1500-2000 j/kg and Bulk shear around 40 Kts late this afternoon and early eve. A short wave disturbance now seen on WV imagery moving into E UT-W CO will push through SE CO this afternoon. This will set off SCT storms over the Plains that will congeal into an MCS by early evening over extreme E CO and W KS. The latest HRRR runs and the 4km NAM are in good agreement with the evolution of convection this afternoon. Storms will initially form from 18-19Z over the S Sangres and Spanish Peaks Region, then coverage will expand to the NE along a diffuse dry line. A broken line of storms should then intensify and spread to the E-SE, moving into OK and SW KS by early eve. Svr Parameters will support all types of severe Wx...but the greatest threats will be for hail up to around golf ball size, and wind gusts in excess of 60 mph. This threat will be greatest over E Las Animas County and all of Baca County late this afternoon. Temps today will be considerably higher than yesterday...with highs reaching the lower to mid 80s over the Plains and 60s-70s for the Mts and high valleys. Expect clearing skies from W to E tonight, which will lead to cool but seasonable overnight Lows, mainly in the 40s-lower 50s for the Plains and 30s for the high valleys. Rose .LONG TERM...(Sunday through Friday) Issued at 400 AM MDT Sat Sep 17 2016 .Sunday and Monday...Upper level ridge develops over Colorado with dry air aloft continuing to advect into the region from the west. Anticipate warm and dry weather both days. With 700mb temperatures around 10C to 12C, high temperatures will approach 90 degrees on the plains both days, but temperatures will be at least several degrees shy of the daily record highs. .Tuesday...Upper trough moves into the Pacific Northwest on Tuesday. Southwest flow ahead of the trough will bring moisture northward into Colorado. Moisture appears to originate from a potential tropical system which will develop off the coast of Mexico. NHC currently has this system as a disturbance, and they have a high probability of tropical cyclone formation. With a lee trough over the plains keeping deeper low level moisture to the east, chances for convection late Tuesday appear to be confined to the mountains. .Wednesday through Friday...GFS and EC start showing differences with the track of the disturbance over the Pacific Northwest. EC is faster moving the system to the east while the GFS is slower and digs the trough into the Great Basin. Both models suggest that diurnal convection will stay mostly over and near the mountains, with generally downslope flow on the plains. The GFS brings a cold front close to the northern portions of the CWA on Thursday. If the front moves further south, upslope flow behind the front will bring increased low level moisture with a better chance for convection developing on the plains. --PGW-- && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) Issued at 400 AM MDT Sat Sep 17 2016 Some low cigs and patchy FG over the far SE Plains this morning...mainly near the KS and OK borders, and should not affect the TAF sites. Looks like storms today will be primarily well east of I-25, so will leave mention of TS out of the TAFs, but an ISOLD storm near the TAF sites cannot be ruled out this afternoon. Most of the storms today will be SE of a line from KTAD to KLHX to KITR. Rose && .PUB Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...ROSE LONG TERM...PGW AVIATION...ROSE
Area Forecast Discussion
National Weather Service Blacksburg VA
428 AM EDT Sat Sep 17 2016 .SYNOPSIS... High pressure, both at the surface and aloft, will weaken and shift east of the region through Sunday. An upper trough and associated cold front will move into the region Sunday, taking until Monday to move through the Piedmont. High pressure will build over the region by Tuesday and linger through the end of next week. && .NEAR TERM /THROUGH TONIGHT/... As of 400 AM EDT Saturday... High pressure off the northern Mid-Atlantic coast will shift east in response to an upstream trough/cold front approaching from the Midwest. However, it will not do so soon enough to prevent another mostly cloudy, relatively cool/mild day compared to most days this month, which have been well above normal. The low clouds are expected to erode across the Piedmont and west of the Alleghany front by afternoon and in most areas by evening as the upper trough/front continue to move into the region from the west. However, this will not be soon enough to allow temperatures to warm yet back to the pre-wedge levels we saw much of this past week. Precipitation is expected to be scarce again today. Most synoptic and short-range models indicate that the best and initial dynamics associated with the upper trough will move northeast toward the Great Lakes/eastern OH valley. Showers and a few thunderstorms will likely approach the northwest border of the CWA late in the afternoon/evening but probably stop short of spreading into much, if any, of the RNK CWA. The HRRR and NCEP WRF show little to no precipitation spreading into the RNK CWA this afternoon/evening. The first wave will go by overnight leaving us with just mid/high clouds and little precipitation. Therefore, have confined pops to slight chance/low chance along the western border to near zero along and east of the Blue Ridge. Mentionable pops have generally been confined to just the western most tier of counties, with the highest pops from KBLF to west of KLWB. As noted above, an increase in temperatures is expected today, but should stop short of the 10F above normal readings we have seen most days this month. Max temperatures today will be entirely dependent on when the low clouds diminish. If this occurs late morning, as opposed to the afternoon, advertised readings may be too cool. Have leaned toward the cooler GFS gridded temperatures as it seem to have the best depiction of the wedge air mass. Minimum temperatures Sunday morning will be well above normal, mostly in the 60s. We should be seeing lows in the 40s and 50s by now! && .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... As of 145 AM EDT Saturday... The cold front that is expected to remain to our west today and tonight, will make gradual headway eastward into and through the region Sunday into Sunday night. Anticipate an increase in the coverage of showers from west to east as the day progresses, especially by the afternoon hours. Chances will be greatest in the east during the evening and overnight hours. Model forecast instability factors are not substantial, nor are they on the low side. The forecast will reflect a slight chance for thunderstorms by mid-day Sunday continuing only into the early Sunday evening hours. The probability of showers will be in the likely category in areas closest to the front. By Monday morning, the front will have just exited, or be on the far eastern edge of the forecast area. Slow progression eastward is still forecast for this feature. It is expected to still be in close enough proximity to allow for isolated to scattered showers across eastern parts of the area. Forecast instability factors are more impressive for thunderstorm development during the peak heating of the day, especially the far eastern parts of the area by the late afternoon. Other showers are forecast across the preferred upslope regions of southeast West Virginia during the morning hours thanks to residual low level moisture and an increasing upslope, northwest flow in that region in the wake of the cold front. Surface high pressure is expected to build across the Ohio Valley By Monday night, and take on a west-east orientation with its axis reaching the Delmarva peninsula by Tuesday night. Aloft, an upper ridge is also expected to develop over the Tennessee and Ohio Valleys. As geopotential heights build across the region, so too will 850 mb temperatures. Late night and early morning fog will be common through the period, especially Sunday night and Monday night. Despite the passage of a cold front, temperatures during this portion of the forecast will continue to remain above normal for this time of the year by five to ten degrees. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 330 PM EDT Friday... High pressure, both surface and aloft, is expected to dominate the region much of this period. An upper level trough is progged to become a closed low over the southeastern states as it begins to interact with Tropical Storm Julia, drifting west again back toward the southeast U.S. coast. An upper level ridge will build east from the Gulf States Wednesday and center itself over the Carolinas by next weekend. This ridge could take Julia westward across Florida and into the Gulf of Mexico. For the immediate area, this ridge will bring several days of warmer than normal temperatures and little chances for rain. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... As of 200 AM EDT Saturday... Weak wedge holding across the area with widespread MVFR cigs already in place. Main question will be whether or not these evolve into any IFR cigs as the night progresses. Based on guidance and current trends, this seems reasonable, so have advertised about a four hour window of IFR cigs at most sites in the 10Z-14Z time frame, after which cigs should improve to MVFR, and most likely to VFR in the 16Z-18Z time frame as the wedge continues to weaken. HRRR and other models show little in the way of meaningful precipitation reaching the CWA today, so have not advertised. Feel that this will remain west to northwest of the CWA, closer to the upper dynamics with an approaching short wave and not be able to penetrate the weakening wedge air mass to any appreciable degree. The cloud cover will probably prevent fog development to much extent, except possibly at KBCB and KLWB. Areas of HZ may be expected in the ROA/BCB/LYH area through mid- morning. Later today and into the evening, high clouds will begin to overspread the region from the west. Winds will remain mostly E-SE through the period at speeds of 5-7kts with low end gusts possible during the daylight hours at KBLF. Medium confidence in cigs throughout the TAF valid period. Medium to high confidence in vsbys through 14Z, then high confidence in VFR vsbys through the remainder of the TAF valid period. Medium to high confidence in wind speed/direction through the TAF valid period. Extended aviation discussion... Approaching cold front edges east but remains well west of the mountains Saturday night. Wedge front dissipates. This will leave improved ceilings overall Saturday night/Sunday morning in comparison to today. However, widespread mid/high clouds will overspread areas west of the Blue Ridge. Appears best chance of seeing pockets of sub-VFR cigs early Sunday will remain along the KBLF-KLWB corridor with showers just ahead of the front. Patchy MVFR fog will be possible each of the Alleghany front early Sunday. Sunday-Monday still looks unsettled as a cold front drifts slowly east across the region. Expect threat of showers and a few thunderstorms with possible sub-VFR cigs/vsbys espcly later Sunday into Sunday night mountains, and across the east later Sunday night into Monday. Anticipating a return to more widespread VFR Tuesday into Wednesday with weak high pressure building in behind the front through midweek. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...RAB NEAR TERM...RAB SHORT TERM...DS LONG TERM...RCS AVIATION...RAB
Area Forecast Discussion
National Weather Service SAN ANGELO TX
325 AM CDT SAT SEP 17 2016 .SHORT TERM... (Today and Tonight) Bulk of the evening convection has now dissipated across West Central Texas early this morning. Models have struggled to handle the convection over the last few days across West Central Texas, with the HRRR handling the short term better than the other models. Thus, will lean towards its solution as a first guess to start the forecast, with scattered convection developing late this afternoon across the western portions of the area, mainly west of an Abilene to San Angelo line. Like has happened the last few days, expect this convection to spread east across the area into the evening hours. As for temperatures, will not deviate much from what we have seen the last few days. Readings have managed to climb into the upper 80s and lower 90s across the area, and should be in the same range today. .LONG TERM... (Sunday through Friday) On Sunday, an upper level ridge will be centered across South Texas/northern Mexico. A subtle upper level shortwave trough is forecast to swing across North Texas which may aid in the development of scattered showers and thunderstorms Sunday afternoon, mainly across the eastern half of the forecast area. Any shower and thunderstorm activity should dissipate by early evening. High temperatures will be well above seasonal normals, in the low to mid 90s. An upper level ridge will dominate the weather across West Central Texas through much of the upcoming work week. Generally dry conditions are expected along with above normal temperatures. Highs through the first part of the work week will be in the low to mid 90s, with overnight lows in the upper 60s to lower 70s. The center of the upper level ridge is then forecast to shift toward the South Atlantic states, which will result in slightly cooler temperatures for the second half of the work week. Expect highs mainly in the upper 80s to lower 90s, with overnight lows in the in the mid to upper 60s. The next upper level trough is forecast to approach the area next weekend, possibly bringing an increasing chance of showers and thunderstorms. && .PRELIMINARY POINT TEMPS/POPS... Abilene 90 69 93 72 / 30 20 20 5 San Angelo 92 69 95 71 / 30 20 10 5 Junction 91 70 95 71 / 20 10 20 5 Brownwood 91 70 93 70 / 20 20 20 5 Sweetwater 89 69 91 71 / 30 20 10 5 Ozona 91 69 93 70 / 20 10 5 5 && .SJT Watches/Warnings/Advisories... None. && $$ 07/Daniels
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
534 AM MDT SAT SEP 17 2016 .AVIATION... 12Z TAF CYCLE Area of showers and storms continues across the northeast highlands near KLVS northeastward to just south of KRTN. Isolated storms will remain possible across the eastern plains through the morning hours. Very dry air aloft will keep areas west of the central mountains convection free today. Favored area for afternoon storms will be across the southeast plains, including KROW. A few afternoon storms are also possible across the far northeast plains. Dry air will spread eastward overnight, ending convection across the east after midnight. 33 && .PREV DISCUSSION...350 AM MDT SAT SEP 17 2016... .SYNOPSIS... A heightened threat of severe thunderstorms is expected for one more day across much of eastern New Mexico today before a drier and much less active pattern develops Sunday and Monday. Much of western New Mexico should remain storm free through the weekend. A closed low aloft developing southward just offshore of far southern California today will remain nearly stationary through Monday before opening up and lifting northeast early next week. After the drying trend to start the new week, this system will pull moisture northward again and enhance thunderstorm chances from Tuesday through Wednesday. A much stronger low pressure system could deliver significant changes for late next week. && .DISCUSSION... Cluster of showers and thunderstorms in the vicinity of Los Alamos and Santa Fe with isolated activity now beginning to develop/expand farther east across the northeast highlands per latest model trends. Latest RAP objective meso analyses suggest a fairly broad region of modest upper level divergence just north of a 250-300mb jet axis that continues to cut across southern New Mexico. That coupled with lift ahead of positively tilted shortwave trough crossing the central Rockies should provide favorable environment through remainder of the morning for isolated to scattered SHRA/TSRA. Made some minor adjustments to PoP/wx for NC/NE areas. Elsewhere, areas of stratus have slowly expanded along/east of the central mountain chain but have yet to see signs of convective precip development for EC/SE zones. Appears the focus will be just east of the NM/TX line but 06z NAM continues bullish trend thru 18z. Otherwise, main wx concern after 18z will be the potential for severe storms across the east once again, especially the southeast. Boundary layer flow veering to SW and surface dew points in the 40s across the northeast may preclude significant, sustained threat there. But backed low level flow looks to maintain mid 50 to near 60 dew points east of the Pecos River and south of the Caprock region beneath fast westerlies aloft where severe potential should be greatest -- to include much of eastern Lincoln, Chaves, De Baca, Curry and Roosevelt counties. That being said, the latest NAM and GFS not overly impressive with QPF despite impressive instability parameters. So coverage may be more isolated across our CWA with better coverage with east/southward extent. The west should again remain quiet save for the the activity this morning and perhaps isolated activity over the higher terrain NC/NW. Sunday and Monday trending noticeably drier/less active areawide as 50mb heights rise and drier air across the far west and Four Corners advances eastward . Closed low aloft developing southward just offshore of far southern California today will remain nearly stationary through Monday before opening up and lifting northeast early next week. Could get nice bump in moisture across the west later Tuesday into Wednesday. All eyes then shift to what could be an especially dynamic/impactful stretch of weather late next week but significant model differences keeping uncertainty quite high. The GFS continues to show an anomalously deep/large upper low taking aim on the southern Rockies while the 00Z ECMWF has trended deeper than its previous run but weaker than the GFS and thus remains more progressive. We often mention a secondary severe weather season this time of year, and the pattern Thursday-Saturday fits that conceptual model quite well even if the more progressive ECMWF were to verify. Stay tuned... kj && .FIRE WEATHER... A dry west to northwest flow aloft will result in a dry day for all but the far eastern plains today. Isolated thunderstorms will be possible across the eastern plains this afternoon before drier air from the west wins out all areas Sunday. Sunday continues to look like the first day since sometime back in July with no thunderstorms/lightning strikes anywhere in the state. Minimum relative humidity values are forecast to drop below 15 percent across all but the southeast plains Sunday and Monday afternoons. Four Corners high is forecast to build northwestward late-day Sunday into Monday, allowing temperatures to warm above seasonal averages both days. Weather prediction models agree that the upper high will get pushed east of New Mexico Tuesday. The upper high gets shoved east as an upper level low drops into the PACNW, sending a weak upper low off of the southern California coast northeastward. Monsoon moisture will increase across western New Mexico in southwest flow aloft head of the California low. This moisture and the associated showers and thunderstorms spread east across the remainder of the forecast area Wednesday and continue through at least Friday. Model solutions diverge next weekend. GFS wants to deepen the upper trough/closed low as it drops southeastward into the Great Basin. ECMWF is farther north until the trough moves east of the Rockies, then it splits the low with the southern portion deepening over the southern plains. These differences would result in major sensible weather differences across NM next weekend. GFSensemble mean is not too far removed from the operational GFS but the same is true for the operational ECMWF and its ensemble mean. 33 && .ABQ WATCHES/WARNINGS/ADVISORIES... None. && $$ 41
Area Forecast Discussion
National Weather Service Albany NY
1024 AM EDT SAT SEP 17 2016 .SYNOPSIS... A low pressure system will gradually approach and move across the region through Monday bringing much needed rainfall to the area. Conditions will become warm and muggy with the passage of the system`s warm front tonight. Temperatures will run 10 to 15 degrees above normal. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Current forecast in good shape. Precipitation across western NY has been weakening as it moves east in agreement with HRRR forecast. Nudged back POPs across NW CWA slightly for late afternoon and early evening. Onset of persistent precipitation looks like it will take until at least 03z to start. Meanwhile, for the remainder of today, high level cirrus clouds will continue to stream into the region well ahead of an approaching low pressure system. Overall cloud coverage will be on the increase thickening and lowering especially later in the day. Chances for showers moving into the western Adirondacks and western Mohawk Valley increase as the system`s warm front approaches. Heights will begin to fall aloft as the weakening upper ridge shifts farther offshore and a trough moves across the Great Lakes region. Southerly winds will increase across the area during the day becoming gusty. Winds will funnel up the Hudson River Valley where they should be the strongest. Despite the increasing cloud cover, the southerly flow will help boost temperatures to above normal again with highs a couple degrees warmer than Friday. Also dew points will rise through the 50s as the warm front gets closer to the region. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... Much needed rainfall on the way as slow moving low pressure system approaches and crosses the region. The system`s warm front is expected to lift across the region tonight ushering a humid airmass in with dew points rising into the 60s. Then the area will be in the warm sector as the cold front gradually approaches from the Great Lakes region. Aloft will have broad southwest flow and will have to wait on a short wave trough to help push the boundary through Monday. Showers are expected to overspread the area tonight with numerous showers along with chances for thunderstorms Sunday into Monday. The better chances for rainfall will be to the south and east of the Capital District Sunday night into Monday ahead of the cold front as it moves across area. The threat for thunderstorms is introduced tonight as negative showalter values move into the region. The mention of thunder is maintain into Monday. 0-6 km bulk shear values are expected to be 30 to 40 knots however the mid level lapse rates remain rather weak 5.5-6 C/km. Overall expecting a widespread rainfall of 1 to 1 1/2 inches across the local area. The system will tap into tropical moisture from the Gulf of Mexico with precipitable water levels increasing to over 1.5 inches ahead of the cold front so some of the storms could produce some heavy downpours leading to ponding of water in low lying and poor drainage areas. It will be warm and humid through the weekend into early next week. Temperatures will be 10 to 15 degrees above normal with dew points in the 60s until the passage of the cold/cool front during the day Monday. && .LONG TERM /TUESDAY THROUGH FRIDAY/... A relatively quiet extended forecast is expected into late next week with a secondary cold front moving through on Tuesday...and high pressure building in for the mid week into THU. A cold front may bring some isolated to scattered showers late FRI. TUE-TUE Night...An upper level trough impacts the region with isolated showers to scattered instability showers mainly north and west of the Capital District/Berkshires according to the latest GFS/ECMWF/CAN GGEM. A secondary cold front will be moving through the region with weak cold H850 cold advection...as H850 temps fall to +6C to +8C from the Capital District north and west...and +8C to +11C south and east. High pressure will be ridging in from the Midwest and Great Lakes Region. Highs will start above normal in the mid 70s to lower 80s in the valleys...and upper 60s to mid 70s over the hills and mountains. Lows will range from the upper 40s to lower 50s over the Catskills and southern Adirondacks to mid and upper 50s over the rest of the region. WED-THU...The mid and upper level flow becomes more zonal by WED night. A large sfc anticyclone builds in over the Northeast...and East Coast with lots of synoptic-scale subsidence. Highs will trend closer to seasonal normals on WED but will still be about 5 degrees above normal for late Sept. Lows WED night in a decent radiational cooling environment will be in the upper 40s to mid 50s. Some weak low/mid ridging tries to build in aloft for THU...and the sfc high drifts off the New England Coast. Strong low to mid level warm advection commences with H850 temps rising back a couple standard deviations above normal with +13C to +15C readings. Highs on THU with increasing high clouds will be in the upper 70s to around 80F in the lower elevations...and upper 60s to mid 70s over the higher terrain. THU night-FRI...In the relatively flat mid level flow...a weak cold front approaches THU night into FRI. The moisture convergence looks weak with this boundary at this time. Only a slight chc of showers was kept in the grids from the mid Hudson Valley north and west for FRI. Temps will finish above normal and similar to THU. Overall...temps look to be above normal...and pcpn below normal in the long term. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... High pressure continues to move east of New England this morning. A warm front will slowly lift north/northeast from the Great Lakes Region and Ohio Valley today with some rain moving in tonight. Some IFR/LIFR mist/fog will dissipate at KGFL/KPSF especially between 12Z-13Z...with VFR conditions returning. VFR conditions will remain into this evening at all sites. Mid and high clouds will continue to gradually increase into this afternoon. It will be breezy. The leading edge of warm advection rainfall/showers should arrive between 01Z-05Z/SUN. VCSH groups are used initially. The cigs and vsbys should begin as VFR...but gradually lower to MVFR levels overnight....and perhaps IFR btwn 09Z-12Z. For now...have MVFR CIGS/VSBYS. The winds will be light to calm at KGFL/KPOU/KPSF early this morning...but southerly at around 10 kts at KALB due to the funneling effect up the Hudson River Valley. The winds will increase from the south at 8-15 kts with some gusts close to 25 kts at KALB this afternoon. The winds will lighten slightly to 5-10 kts overnight at KGFL/KPOU overnight...but will be 10-15 kts at KPSF/KALB with gusts around 20 kts. Low-level wind shear maybe needed at KGFL/KPOU after 06Z if confidence increases. Outlook... Sunday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Monday: Moderate Operational Impact. Chance of SHRA...TSRA. Monday Night: No Operational Impact. NO SIG WX. Tuesday: No Operational Impact. NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: No Operational Impact. NO SIG WX. && .FIRE WEATHER... Wind gusts into 20s today and this evening... A low pressure system will gradually approach and move across the region through Monday bringing much needed rainfall to the area. Showers are expected to overspread the area tonight with numerous showers along with chances for thunderstorms Sunday into Monday. The better chances for rainfall will be to the south and east of the Capital District Sunday night into Monday. Overall expecting a widespread rainfall of 1 to 1 1/2 inches across the local area. && .HYDROLOGY... A low pressure system will gradually approach and move across the region through Monday bringing much needed rainfall to the area. Showers are expected to overspread the area tonight with numerous showers along with chances for thunderstorms Sunday into Monday. The better chances for rainfall will be to the south and east of the Capital District Sunday night into Monday. Overall expecting a widespread rainfall of 1 to 1 1/2 inches across the local area. The system will tap into tropical moisture from the Gulf of Mexico with precipitable water levels increasing to over 1.5 inches ahead of the cold front so some of the storms could produce some heavy downpours leading to ponding of water in low lying and poor drainage areas. Based on the USGS (waterdata.usgs.gov/nwis/rt) streamflow are running at less than 25th percentile across most the hydrological forecast area. Precipitation departures so far this year: Albany NY: -3.54 inches Glens Falls NY: -6.28 inches Poughkeepsie NY: -10.44 inches Bennington VT: -7.24 inches Pittsfield MA: -8.03 inches The U.S. Drought Monitor was released on September 15th and shows drought conditions have worsened across portions of the Northeastern United States as much of the region experienced above-normal temperatures and below-normal precipitation. A (local) Drought Information Statement was issued Friday evening (ALBDGTALY). For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...IAA NEAR TERM...IAA/OKeefe SHORT TERM...IAA LONG TERM...Wasula AVIATION...Wasula FIRE WEATHER...IAA HYDROLOGY...IAA
Area Forecast Discussion
National Weather Service Columbia SC
1115 AM EDT SAT SEP 17 2016 .SYNOPSIS... High pressure will ridge into the forecast area from the north today. Julia will linger just off the South Carolina coast through Sunday then dissipate. Moisture associated with Julia will stay east of the Midlands. A weak cold front will cross the area Monday. High pressure will return to the area by the middle of next week. && .NEAR TERM /THROUGH TONIGHT/... Low clouds will linger over the Midlands through the remainder of the morning, dissipating after noon. Surface high pressure will continue to ridge into the Carolinas and Georgia from the north with Julia meandering off the coast today into tonight. A mid-level capping inversion will limit convective development this afternoon. Scattered cumulus are expected from daytime heating but are not likely to develop into showers. The HRRR does show isolated showers moving inland from the coast but dissipating before they reach the forecast area. Tonight, upper level ridging over the southeastern states will retreat to the southwest as a trough moves into the Mississippi River Valley. Lows tonight will be in the mid 60s to lower 70s. Models are suggesting deeper moisture and lighter low level winds. It is likely that stratus and fog will develop again tonight through late Sunday morning. && .SHORT TERM /SUNDAY THROUGH MONDAY/... Julia is forecast to linger off the South Carolina coast early next week. An upper level trough crossing the Mississippi River Valley Sunday will cross our area on Monday. The associated weak cold front should move into the area Monday. The models are consistent with shallow moisture Sunday. The NAM and GFS MOS have pops less than 20 percent, so continued to forecast dry conditions. The shallow moisture and nocturnal cooling with light wind should result in areas of fog during the early morning hours. There should be increased instability Sunday night and Monday associated with the upper trough. Have indicated a chance of showers and thunderstorms Sunday night into Monday evening. The temperature guidance was consistent with highs in the upper 80s and lower 90s along with lows in the upper 60s to lower 70s. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... The GFS and ECWMF show surface ridging extending into the forecast area from the north through the medium-range period. An upper trough is forecast move off the coast Tuesday with ridging building into the area. Julia is shown lingering near the Southeast coast at least through early in the period. Much of the moisture associated with Julia or the trough is depicted to stay east or south of the forecast area. The GFS and ECMWF MOS have pops less than 30 percent through the period with temperatures mainly above normal. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... IFR ceilings will dissipate over the next few hours. No convection is expected to impact the terminals today. Models have been consistent and are in good agreement indicating restrictions late tonight and into Sunday morning. Deeper moisture and lighter low level winds will support low stratus and fog development. MVFR/IFR ceilings and visibilities likely after 07z tonight, with the possibility of lifr by early Sunday morning. EXTENDED AVIATION OUTLOOK...Early morning fog and stratus remain a possibility through the period with a chance of mainly afternoon/evening thunderstorms early next week. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Charleston SC
1016 AM EDT Sat Sep 17 2016 .SYNOPSIS... The region will remain situated between Tropical Depression Julia meandering off the Southeast U.S. coast and inland high pressure through early next week. A cold front will advance into the region by the middle of next week, stalling just south of the region as high pressure builds from the north. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... An inland wedge of high pressure will hold firm today as Tropical Depression Julia continues to meander well offshore and weaken. Broad, synoptic-scale subsidence and extensive mid-level dry air induced by a strong southwest-northeast oriented upper level ridge extending from from the eastern Gulf of Mexico, across the Southeast U.S coast to offshore the Mid-Atlantic states will support another dry and warm day. Only slight chance for a few afternoon showers across mainly the Charleston Tri-County area as a sea breeze develops. Broad scale subsidence and minimal instability will limit coverage and intensity. Extensive stratus this morning will slowly burn off through early afternoon. Given a fairly high sun angle and warm thicknesses, temps should rebound quickly once even a few breaks start to develop. Thus, despite continued overcast skies in southern SC, we feel confident that highs will reach the upper 80s by the end of the day. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... Tonight: High pressure wedging will remain in tact as Julia transitions to a remnant low well offshore. Temperatures will drop steadily after sunset as any lingering cumulus away from the coast should dissipate with the loss of insolation. Any isolated showers that can spawn in the northeast low-level flow look to remain confined to the coastal waters where boundary layer moisture will be the most plentiful. Conditions favor another round of stratus either developing over the area or propagating in from the northeast after midnight. Most of the statistical guidance show some degree of a stratus deck prior to sunrise, which coincide with the low 1000 hPa condensation pressure deficits noted in the 17/00z NAM12. The boundary layer will decouple inland, so some of the stratus could translate to some fog. Lows will range from the upper 60s well inland to the upper 70s at the beaches. Sunday through Tuesday: Surface high pressure covering the eastern United States and ridging aloft will cause the remnants of Julia to further weaken offshore. Higher PWATs will remain further offshore as the high pressure inland wins out. Though, isolated showers associated with the weakening system may work across the coastal waters and possibly reach the South Carolina beaches. Heights aloft will begin to fall Sunday night as broad troughing shifts eastward from the Great Plains. The remnants of Julia will deteriorate rapidly into a wave as the upper level wind speeds increase during this time. A cold front will approach the area Monday, pushing the remnants of Julia out to sea. Increasing moisture ahead of the front combined with increased instability justify chance POPs by Monday. This should be the best day for thunderstorm potential, especially in the afternoon. However, given the low amplitude of the trough and the modest WAA ahead of the front, the severe threat remains low. The front will cross through our area Monday night and stay to our south on Tuesday. High pressure building into our area from the north will bring drier conditions. Temps will be near to a few degrees above normal thanks to the ridge overhead and increasing WAA early next week. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... The cold front will be far to our south Tuesday night while high pressure to the north builds into our area and brings drier conditions. The high will dominate our weather through the end of next week. Showers should remain mostly confined to the coastal waters. Though, it`s possible some could move onshore, especially towards the end of this time period. Hence, we have periods featuring slight chance POPs for the coastal counties while further inland is dry. Temperatures will generally be near normal. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... KCHS: As expected, low stratus has reached the terminal a few hours ago with cigs OVC006. Intermediate observations from the ASOS ceilometer have been as low as OVC300-400 or below alternate minimums. Expect LIFR to persist through 14z before rapidly improving. The stratus layer is rather thin per RAP soundings. Should see VFR through early evening. Conditions point to a potentially more widespread stratus event tonight. KSAV: The leading edge of a stratus deck is on target to reach the terminal by 12z. Will highlight cigs just below alternate minimums through about 1330z with conditions rapidly improving thereafter. Expect VFR through this evening. Conditions point to a potentially more widespread stratus event tonight. Extended Aviation Outlook: Showers may bring brief flight restrictions Sunday and Monday, especially in the afternoon. && .MARINE... Today: The pressure gradient will remain pinched today between inland high pressure and Tropical Depression Julia. The tightest gradient will remain confined to the Charleston County and Georgia offshore waters where NE winds 15-20 g25 kt will persist. Expect slightly lower winds elsewhere. Long period easterly swells from Julia and wind wave will support combined seas 2-4 ft nearshore waters from Edisto Beach south to the Georgia coast with 4-6 ft over the Charleston (AMZ350) and Georgia offshore waters (AMZ374). A Small Craft Advisory will remain in effect for AMZ350-374 mainly for seas and frequent gusts to 25 kt. Tonight: Conditions will finally begin to improve as Julia continues to wind down and inland high pressure holds form. The tighter gradient looks to shift farther offshore which will allow winds to gradually diminish. Seas will diminish a bit as well, but 6 ft seas will linger over the Charleston County and Georgia offshore waters through this evening. Sunday through Wednesday: Julia is forecasted to weaken off the Southeast U.S. coast on Sunday. Our waters will remain on the western periphery of the weakening circulation, which will allow northeast winds to prevail. The remnants of Julia will be pushed further offshore on Monday as a cold front approaches the waters. The front will pass through our area Monday night, moving south of our area on Tuesday. High pressure to our north will then build into our area, generating a return to northeast winds. Seas are expected to subside to 1-2 ft by Monday night. Rip currents: Easterly swell from Julia combined with astronomical influences from the current full moon will keep the rip risk at moderate today. An elevated risk will continue through Sunday as the swell from Julie slowly fades. && .TIDES/COASTAL FLOODING... A Coastal Flood Advisory will likely be needed for all or portions of the coast with the evening high tide cycle. Shallow salt water flooding will be possible once again Sunday, mainly during the evening along the South Carolina coast. As we move further from the full moon and the northeast flow decreases as Julia weakens Sunday, the threat for shallow coastal flooding should subside. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...Small Craft Advisory until 11 PM EDT this evening for AMZ350- 374. && $$ NEAR TERM...JRL SHORT TERM... LONG TERM... AVIATION... MARINE... TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service State College PA
1159 AM EDT SAT SEP 17 2016 .SYNOPSIS... A moist southerly flow ahead of a slow moving cold front will bring an increasing chance for showers across the western half of the state later this morning and this afternoon. The chance for showers and scattered thunderstorms will increase elsewhere across central the central mountains and Susq Valley late today into Sunday. Rainfall totals by late Sunday will likely be near one inch in many locations. A few places could see slightly heavier amounts. Improving conditions with decreasing humidity will occur Monday through at least early Thursday as a large area of high pressure builds in from the Midwest. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... Showers in a wide line stretching from western NY into the Laurels. The rainfall is not heavy by any means. Operational HRRR and RAP keep insisting on weakening the showers in time. However, some bit of expansion/filling-in has been noted over the last 4-5 hours. Again, this stuff is jnot heavy, but is going to dampen many outdoor activities. The current trajectory of the rain is just about stright to the NE. The motion and orientation of the area of showers will keep it over the northern mountains for a few hours. There is an area of clearing just to the west of KBFD which stretches all the way into southern OH and is allowing for better surface heating and advection of 70+ dewpoints to the north. This is the area to watch for deep convection/thunder and any worry of severe weather for later this afternoon and evening. Prev... Areas of strato cu were noted across the South-Central Mtns...and especially over the Lower Susq Valley where skies were bkn-ovc early today as a result of a southerly 925-850 mb flow. Partly cloudy skies in the form of cirrus were observed between the route 219 and I-99/RT 220 corridors. Conditions will stay dry through 12z and beyond over most of the CWA. Low temps around sunrise will vary from around 50F over the western Poconos, with mid to upper 50s over the northern and western mtns. Readings over portions of the Middle and Lower Susq Valley will be in the 60-65 degree range as a result of the bkn- ovc strato cu deck. Moisture will continue to increase today ahead of slow moving frontal system approaching from the Ohio Valley overnight and tomorrow. The chance for showers will be on the increase during the late morning/early afternoon hours west of the I-99 corridor...with locations just east of the I-99/RT220 corridor likely staying dry until 19-20Z per the last several runs of the HRRR that depict a lead band of convection (showers and scattered TSRA) forming along a prefrontal trough. The deterministic NAM and SREF are most aggressive in bringing showers east today, while the bulk of other operational guidance (HRRR and GEFS) are slower and suggests more in the way of just scattered showers and isolated thunderstorms in the increasingly humid and unstable airmass. A pair of weak/fast moving upper jetlets will lift NE from eastern Ohio and cross far NW PA...bringing the most frequent/heaviest showers and embedded tsra to that region this afternoon/evening. SPC has roughly the NW 1/3 of the CWA in a Marginal Risk for SVR TSRA this afternoon and evening...thanks to a 30-40kt southerly 925-850 mb jet with decent streamline convergence just to the west of this wind max. Further east...gradually weaker llvl winds and slight diffluence/anticyclonic curvature to the flow should minimize the areal coverage and intensity of the shra and tsra. The showers through 21z will be confined mainly to the western half of the state. 925-850 mb diffluent flow and speed divergence will help to minimize the areal coverage rainfall amounts from showers/isolated TSRA. Highs this afternoon will be a few degrees warmer than Friday... ranging from the mid 70s north to the lower 80s in the southeast. && .SHORT TERM /7 PM THIS EVENING THROUGH 6 AM SUNDAY/... Cfront will gradually push east across the region after midnight and slow as several weak waves of low pressure at the sfc and aloft ripple newd along it. POPs through 12Z Sunday will be likely to categorical across the NW half of the CWA...with 35 to 60 POPs near and to the SE of Interstate 81. Low temps early Sunday will be mild and in the 60s. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Little change in the high probability for frequent showers and scattered TSRA Sunday and Sunday night across Central and Sern PA as the cfront edges slowly sewrd. some drying and lower pops should spread into the NW mtns Sunday afternoon/evening...but will maintain chc pops there through around midnight. Afterward, there are no other notable times in the long-term period when it is worth drawing POPs over 20. Even then only over the far northern tier as weak fronts try penetrate the force field over central PA. Low pressure rolls through northern Ontario and Quebec early in the period. The associated cold front checks in but does not check out of PA as the boundary layer and upper flow become nearly parallel. PW does not quite reach 2 inches, but the constant southerly flow around the high pressure off the coast will yield a long period of deep moisture. The front finally pushes through Sunday night and early Monday. This is a bit of a slow-down from previous forecasts, but probably to be expected with an already- sluggish front and no real kicker of an upper trough. A minor surface wave tries to form over the central Appalachians and track over MD/SE PA right as the front finally looks to move out. So, the heaviest rain could come to the southeastern zones on Sunday night and early Monday. The first part of the new week looks dry, with a surface high overhead. A very weak and moisture-starved front moves along in the progressive westerly flow and could make a passing shower across the far north on Tues. But, again, it holds almost no hope of rainfall for anyone, as the Gulf is cut off and drought does beget drought. A warm front and perhaps light precip will set up just to our north later in the week as we go from temps "only" 0 to 5F above normal back to temps some 10F warmer than normal by mid-week. There might even be a run at 90F in the far southeast later in the week. There is a hint in many of the models that the front just to our north may try to inch southward in backdoor fashion on Friday. However, we will keep day7 dry for now. Temps through the period will remain 5 to 10F above normals for maxes and mins - and mins might be 10+ above normal during the weekend with all the clouds and moisture. && .AVIATION /16Z SATURDAY THROUGH WEDNESDAY/... Showers passing rather slowly per earlier expectations. Orientation and movement still keep them mainly to the NW of and AOO-UNV-IPT line into the mid afternoon. MVFR cigs do cover a large portion of the area, but clearing/VFR over the west will likely self-destruct into TSRA later today. Have kept timing of the major changes in flight categories and winds the same with 15z update. Prev... A cluster of TSRA is already nearing KBFD, but weakening as they do so. Other SHRA across SW PA are also tracking to the NE but could brush KJST as they pass mainly to the north of that location. Isolated to scattered SHRA will impact the western terminals almost all morning, and heating will help to bubble up additional SHRA/TSRA as the afternoon begins. The central mountains including KAOO and KUNV will likely have a mainly dry morning, but the next wave of forcing comes along in the early-to mid-afternoon time frame. Heating will destabilize the atmos and cause SHRA/TSRA in the afternoon - but mainly after 3 PM. Steering flow will push the SHRA to the NE and may impact KIPT mid- to late-afternoon. Low-end VFR and high-end MVFR cloud slab over most of the eastern half of the area will lift some and break up. But, heating will be limited - at least this morning - so destabilization will be less likely until very late in the day. Sunset will help to decrease the amount and coverage of showers, but a focus of some sfc convergence remains over the NW and central terminals. Expect KMDT and KLNS to keep dry for the longest period, but by 12z Sun, they may also be wet. MOS guidance for KIPT drops them into IFR cigs later tonight. With high moisture and winds which go calm/light, this seems reasonable. A frontal boundary will be tough to draw tonight into Sunday night, but slightly drier air will work in Sunday night and Monday. Until then, SCT SHRA and ISOLD TSRA are expected for most of the area. Outlook... Sun...Scattered impacts as a slow moving frontal system moves through the region. Mon-Wed...no sig wx. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert NEAR TERM...Dangelo/Lambert SHORT TERM...Lambert LONG TERM...Dangelo/Lambert AVIATION...Dangelo
Area Forecast Discussion
National Weather Service Grand Forks ND
951 AM CDT SAT SEP 17 2016 .UPDATE... Issued at 943 AM CDT Sat Sep 17 2016 Only minor tweaks needed to sky cover needed for this update. The RAP 1000-850 mb RH field has a very good handle on the cloud cover across the northeast area of the forecast area. This cloud deck is progged to slowly move eastward out of the area by mid-afternoon. High temperatures in the mid 50s in this area still look on track with low to mid 70s across the valley and westward with sunshine. UPDATE Issued at 632 AM CDT Sat Sep 17 2016 Minor adjustments made to sky cover as the back edge of overcast area associated with departing upper low gradually advects eastward. Expectation is area clear out by mid-afternoon. Did change wx type to drizzle in limited area of remaining POPs in the far northeast. && .SHORT TERM...(Today and tonight) Issued at 229 AM CDT Sat Sep 17 2016 Primary challenge for the rest of tonight and today will be departure of some light rain showers over northwest Minnesota associated with an upper low/trough over wrn Ontario/northern MN. An upstream short wave ridge will move move over the Dakotas today and bring dry weather to the eastern Dakotas and RRV, with some lingering showers through the morning in the far northeast. Associated surface ridge will be over the Devils Lake basin at 12Z this morning and move into the eastern zones by 00Z Sunday, setting up return flow across the eastern Dakotas tonight. This will bring much warmer overnight lows to western zones tonight, generally in the mid 50s...about 10 deg warmer than last night. .LONG TERM...(Sunday through Friday) Issued at 229 AM CDT Sat Sep 17 2016 The next concern will be winds in the western zones on Sunday as a sfc trough associated with low pressure moving across central Canada moves east. A well mixed atmosphere by mid-day Sunday, with the GFS showing an adiabatic layer to around 800 mb in Devils Lake (as well as a potent jet max moving across ND), will bring breezy conditions west of the RRV. Adjusted winds upward from superblend solution to get wind gusts around 25 to 35 mph Sun afternoon, much more representative than the superblend solution. The strong westerlies will bring daytime highs into the upper 70s to low 80s on Sunday. Kept a chance for some light showers or storms along the Canadian border as the sfc trough moves across southern MB, however best chances for precip remain north of the intl border in region of the left exit region of the upper jet. Subsiding winds will allow Sun night lows to drop into the lower 50s and cooler but dry air on Monday will drop temps back into the lower 70s, possibly the upper 60s across along the intl border. The upper level pattern transitions to SW flow aloft mid-week. Southwest flow aloft will bring a wet period to the area mid to late week. One 500 mb short wave will move northeast from Wyoming into the Dakotas with increasing precipitation chances Wednesday. Then attention turns to the main 500 mb short wave and low which will move into the western US Thu-Sat period. Timing issues noted between the 00z ECMWF and 00z GFS with the ECMWF more progressive and faster in bringing in significant rainfall to the area Friday whereas the GFS over time digs the upper low farther south into New Mexico. But even GFS model would bring up enough moisture for a potential significant rainfall event but more later into next weekend. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) Issued at 632 AM CDT Sat Sep 17 2016 Clear within and west of the Red River Valley. MVFR-IFR east of the valley with TVF on the edge of low cloud deck. Currently clear but may see some more IFR cigs drift in from the north before entire deck shifts east late morning and erodes this afternoon. BJI will be last to clear out in the early aftn. && .FGF Watches/Warnings/Advisories... ND...None. MN...None. && $$ UPDATE...Lee SHORT TERM...Speicher LONG TERM...Speicher/Riddle AVIATION...Speicher
Area Forecast Discussion
National Weather Service Hastings NE
533 AM CDT SAT SEP 17 2016 .SHORT TERM...(Today and tonight) Issued at 351 AM CDT Sat Sep 17 2016 Today will be absolutely beautiful with light winds, mostly clear skies, and highs in the upper 70s across south central Nebraska to near 80 over north central Kansas. A sfc high will track east across Kansas resulting in the light wind, which will shift from westerly to southerly as we head through the day. The primary forecast concern and point of uncertainty will surround the chance of thunderstorms this evening. Moisture will be very limited with dewpoints currently in the 40s to around 50 and these will climb only slightly by this evening into the the lower 50s. A subtle hardly noticeable vort max/upper trough will slide east off the high plains this evening. The 07Z HRRR is the most aggressive with developing showers and thunderstorms across eastern Colorado by late afternoon, which then push east into our western zones predominately after 7 pm. Several WRF models also indicate that this high plains convection could make it at least into our western zones this evening. Therefore, have added a chance of thunderstorms to the forecast for this evening leaning towards the lower superblend POPs. There will be at least a marginal severe weather threat off to our west late this afternoon, but given our feeble instability (SBCAPE 500-1000 J/KG) and the late hour of arrival as we lose diurnal heating it seems that any storms should be weakening as they make it into our western forecast zones. Given decent deep layer shear of 30 kts and at least some initial limited instability, can not completely rule out an initial strong storm or two in our far west from Gothenburg, down to Beaver City, and south into Plainville, KS. Weakening thunderstorms will likely die out before midnight and currently seem unlikely to make it any further east than Highway 281, but this should be watched and updated in future forecasts. .LONG TERM...(Sunday through Friday) Issued at 351 AM CDT Sat Sep 17 2016 Dry conditions remain in the forecast to start of the long term period on Sunday, and are expected to continue into the first part of the upcoming work week. By Sunday morning, models are in pretty good agreement showing zonal to low amplitude northwesterly flow having developed in the upper levels, in the wake of a departing shortwave trough axis. Overall, not expecting a lot of change in the overall pattern as we go through Sunday and even into Monday/Tuesday. Upper level flow remains zonal, with the CWA set up between high pressure building over the southern Plains and a disturbance sliding east across Canada. Models not showing much in the way of waves affecting our area, thus the forecast remaining dry. At the surface, west-southwesterly winds are expected to be in place during the day on Sunday, with high pressure over much of the southeastern CONUS and a frontal boundary working its way in from the west. This boundary looks to push through the area late Sunday night into Monday, but not much in the way of impact is expected outside of a switch to more northwesterly winds and lower dewpoints. High pressure behind this boundary builds into the area for later Monday/Monday night, before sliding off to the east, allowing for southerly return flow for Tuesday. Forecast highs for Sun-Tues remain in the 80s. Looking to the mid-later portions of the week, there is more uncertainty in the forecast, as precipitation chances make a return. The upper level pattern across the Central Plains transitions to southwesterly flow by Wednesday morning, as the ridge axis associated with that southern Plains high gets pushed east of the area by low pressure/troughing moving onto the West Coast. A more organized upper level low pressure system is expected to start working its way east into the Rockies through the Wed-Fri period, but confidence isn`t the highest. There are notable differences between models with the timing/track of this system, with the 00Z ECMWF quicker/further north than the 00Z GFS. Hard to go higher than 20-30% chances at this point, lot of details with any lead shortwaves are yet to be determined. && .AVIATION...(For the 12Z KGRI/KEAR TAFS through 12Z Sunday morning) Issued at 525 AM CDT Sat Sep 17 2016 VFR conditions will persist throughout the TAF valid period. The wind will be light and shift from westerly to south southwest through the period as an area of sfc high pressure slides off to the east. Low level wind shear will increase tonight, but should be below the threshold for including it in the TAF. && .GID Watches/Warnings/Advisories... NE...None. KS...None. && $$ SHORT TERM...Wesely LONG TERM...ADP AVIATION...Wesely
Area Forecast Discussion
National Weather Service Wilmington OH
1046 AM EDT Sat Sep 17 2016 .SYNOPSIS... A moist airmass will remain in place ahead of a cold front, resulting in periods of showers and thunderstorms today and tonight. The front will push through the region Sunday bringing an end to the thunderstorms from northwest to southeast. High pressure will bring a dry and sunny day on Monday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Southwest flow at the surface and aloft continues ahead of a cold front and upper trough across the Midwest. Ahead of these features, a low level jet is evident over the Ohio Valley...on the order of around 40 kt. Low level jet will help pump moisture ahead of the front and also help to produce a decent coverage of showers as is already depicted on radar. Expect thunderstorms to enter the mix as well later today, however overall instability is forecast to be on the weak side. Best chance for higher instability (several hundred J/kg CAPE) for thunderstorms looks to be along/east of Interstate 71. Assuming some CAPE, this combined with the low level jet may allow a few thunderstorms to produce strong to locally damaging wind gusts. High moisture may also lead to heavy downpours although the progressive movement of convection should limit the overall flash flood risk. Still, heavy rainfall could produce localized minor flooding. Re-worked pops/wx based on latest radar trends (showers just now entering far western CWA) and based on the latest HRRR which seems a little faster than recent runs of the NAM or GFS. Also re- worked temperatures, with highs in the mid to upper 70s through the Whitewater/Miami Valleys and mid 80s toward south central Ohio/northeast Kentucky. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... Convection gets hung up southeast of I-71 tonight as cdfnt works into the region. Overall expect the coverage to diminish, but there will be lingering chance overnight. Lows should drop back into the mid 60s. On Sunday, a secondary H5 s/w swings across the Ohio Valley. This will help keep a chance of pcpn along and se of I-71. Highs should only make the upper 70s. Finally as the upper trof swings through Sunday night the pcpn chances will come to an end. Cooler/drier air will begin to filter in and lows will range from about 55 to 60 degrees. With high pressure across the region on Monday, expect the skies to be mostly sunny. The sunshine should be enuf to push highs back into the lower 80s. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... High confidence that this period will be above normal in temperatures and largely quiet in terms of weather. Ridging over the southern US will expand and intensify as strong negative height anomalies dig through southern Canada. A weak cold front will slide through the Great Lakes on Tuesday. This feature will be losing amplitude with time and thus low level forcing not overly strong and mid level forcing is peeling away to the northeast the shortwave trough deamplifies moving through/atop large scale ridging. Did not introduce rain chances in this forecast but small chances may need to be added in future forecasts. Wednesday and Thursday largely looking dry as ridging continues to surge north - and muggy air once again returns to the region by the end of week. Questions begin to arise this late in the forecast on whether shortwaves will track close enough to the area for rain chances primarily Thurs night/Friday. Quite of bit of uncertainty and thus forecast left largely dry save for some small rain chances in west central Ohio closest to stronger flow/moisture advection. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... A shield of SHRA/TS will continue to push NE across IN and northern OH through the AM. A few spotty lingering showers will be possible through 15z, but expect terminals to be mostly dry through late morning. Scattered SHRA/TS across central IN will develop and push east toward western terminals by 15-18z. Activity should push east of TAF sites by 00z Sunday. Brief MVFR VSBYs and CIGs will be possible in heaviest pcpn. Light southerly winds will increase in the late AM/early PM time frame ahead of convection/pcpn as a weak sfc low tracks north of the area. Winds may gust to 15-20kts during the afternoon, with additional storm-driven gusts possible. Expect scattered SHRA/TS to be mostly E of terminals by 00z, with some spotty lingering activity still possible through 03z, especially for eastern sites of KCMH and KLCK. The main concern after 03z will be the potential for MVFR CIGs and VSBYs area- wide as model soundings show that low levels may become nearly saturated. There exists the potential that CIGs and VSBYs may go below MVFR after 06z Sunday, but confidence on timing or exact location precludes inclusion in the TAFs at this time. OUTLOOK...Thunderstorms are possible Sunday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...AR NEAR TERM...BPP SHORT TERM...Sites LONG TERM...Binau AVIATION...KC
Area Forecast Discussion
National Weather Service Indianapolis IN
1054 AM EDT SAT SEP 17 2016 .UPDATE... The Aviation Section has been updated below. && .SYNOPSIS... Issued at 318 AM EDT Sat Sep 17 2016 A cold front will move through the area today, bringing showers and thunderstorms. High pressure will briefly build in for Sunday into Monday, but another front could bring some rain Monday night into Tuesday. Another frontal system could bring more rain late in the week. Temperatures will remain above average. && .NEAR TERM /This afternoon/... Issued at 926 AM EDT Sat Sep 17 2016 Surface Analysis late this morning shows a trough of low pressure over Illinois and Lake Michigan. Water vapor shows a plume of tropical moisture streaming across the lower Mississippi River valley across Indiana to the eastern Great Lakes. Good subsidence and drying was seen in the wake of the plume...across western Illinois. Radar shows the best organized precip echos across central Indiana...moving quickly east. HRRR suggests the current band of precip will be the best threat for the rest of the day. This area of precip should propagate east of Indiana by early afternoon. HRRR suggests a few pop up type showers and storms will be possible along and near the trough passages this afternoon. Forecast sounding continue to keeps decent moisture available through the afternoon with convective temperatures in the middle 70s. Thus an isolated TSRA/shra development cannot be ruled out...chances for precip are expected to continue to diminish as the afternoon progresses and subsidence and drying wets of Indiana continues to build to the east. With plenty of clouds and ongoing rain expected today...trended high temperatures cooler...closer to the 3 hourly mavmos. && .SHORT TERM.../Tonight through Monday night/ Issued at 318 AM EDT Sat Sep 17 2016 Focus is on rain chances through the period. For most of the period, models are close enough that a blend was used. The cold front will still be passing through the area this evening, so kept some low PoPs in during the evening, lingering into the early overnight far south. Surface high pressure will build in on Sunday, even as an upper trough moves across aloft. With the high at the surface along with limited moisture, kept a dry forecast Sunday. Dry conditions will continue through the day Monday with the high in control. A cold front will move into the northern forecast area Monday night. Moisture is limited and upper support weak. Thus only went some slight chance PoPs north. Generally stayed with a model blend for temperatures through the period. && .LONG TERM /Tuesday through Friday/... Issued at 318 AM EDT Sat Sep 17 2016 A weak cold front may produce an isolated thundershower central and south early Tuesday before it moves out of the area. Otherwise... high pressure will bring dry weather rest of tuesday through Thursday as it moves east across the area. Models diverge some late next week as the GFS indicates a cold front may move as far south as northern Indiana by Friday...while the EURO with a stronger upper ridge across our region keeps this front farther north. If the EURO is right it will be dry and quite warm late next week. But given that the previous forecast already has a slight chance of storms north and central next Friday...will continue this slight chance for now. Highs will be in the lower 80s next Tuesday and middle 80s or warmer late next week. Lows will be in the upper 50s to near 60 Tuesday night and in the 60s rest of the long term. Tweaked high temperatures warmer late next week. Otherwise...stayed close to super blend temperatures. && .AVIATION /Discussion for 171500Z TAF Issuance/... Issued at 1054 AM EDT Sat Sep 17 2016 For the update, removed any thunder mention for the day. Relevant parts of previous discussion follow... MVFR flight conditions or lower at times this morning. Then mostly VFR until late tonight with IFR fog possible towards Sunday morning. Could see periods of MVFR or IFR ceilings through early afternoon as cold front moves across the region. Model soundings indicate generally VFR ceilings of 4 thousand feet or higher from mid afternoon on with clouds scattering out some areas tonight. Could see areas of IFR Fog late tonight due to wet ground and radiational cooling. Winds will become southwest up to 10 knots by midday and light tonight. && .IND Watches/Warnings/Advisories... NONE. && $$ SYNOPSIS...50 NEAR TERM...PUMA SHORT TERM...50 LONG TERM....JH AVIATION...JH/CP
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1050 AM EDT Sat Sep 17 2016 .UPDATE... Issued at 1050 AM EDT SAT SEP 17 2016 14Z sfc analysis shows high pressure off to the east of Kentucky while a cold front and low pressure is approaching from the west. Ahead of this front, an area of weakening showers are slowly pressing eastward. For eastern Kentucky any potential for morning convection has shifted off to the northeast with skies mostly clear in the warm sector ahead of the cold front. The latest near term models, including the HRRR, show pcpn holding off for our CWA until at least late afternoon - awaiting the better support associated with the front and mid level trough. Plenty of morning sunshine should help send current temperatures in the mid 70s up into the mid to upper 80s yet again. This will combine with dewpoints in the mid 60s to generate a good amount of instability by the time the front gets here. In addition, veering winds aloft will support the storms becoming organized along and ahead of the boundary. As a result, any of the convection that does develop toward evening could become strong with gusty winds and heavy rains - climbing PWS and slow boundary - the main threat. With the morning clearing, winds have been able to mix down effectively yielding southwest ones around 10 mph at the sfc with gust to 15-20 mph or so. Have updated the forecast through the afternoon with the above in mind. These grids have been sent to the NDFD and web servers. A freshened set of zones were also issued. UPDATE Issued at 620 AM EDT SAT SEP 17 2016 Opted to slow down the arrival of precipitation a bit more today based on latest hi-res model guidance. Many of the models have a very slow movement to the east today and thus, a slower solution seems reasonable. The HRRR seems to be the most progressive with spreading things east, but based on the initialization, it doesn`t seem to be matching current trends. Thus, opting to follow a solution closer to the NSSL WRF/ARW/NMM. && .SHORT TERM...(Today through Sunday) Issued at 304 AM EDT SAT SEP 17 2016 A vort max passing across the region this morning has kicked off some very isolated showers as its worked northward across the area. This activity will continue to lift northward into northeast Kentucky over the next few hours before exiting to the north. Meanwhile...a cold front continues to slowly move eastward and is currently aligned along the Ohio river bordering Illinois and Kentucky with the front stretching northward across Indiana. This front will make very little progress to the east today. Subsidence ahead of the approaching boundary may keep eastern Kentucky dry for much of the upcoming day. All the hi-res models keep precipitation out of eastern Kentucky until at least after 21z...and many don`t have anything until after 00z. Thus, went with a mainly dry forecast, but did bring some low pops into our western zones very late in the day as the front nears. Main rain chances will come tonight into Sunday morning as the front crosses eastern Kentucky. Models continue to show plenty of moisture and lift with the front and thus corresponding pops are quite high. Given this setup, have opted to go with categorical pops as most of the area will see measurable rain with this front. Front will hang up over the area on Sunday, leading to rain chances through the day. The front will finally start to push east late in the day, with rain chances diminishing in the evening. PW`s will approach 1.90 early Sunday, so some locally heavy rainfall will be possible. However, instability remains weak through Sunday, so we may not be able to realize the heavier rainfall potential if instability does not materialize. Regardless, should see some much needed rainfall. Stayed above guidance on highs today as the delayed onset of rain will allow the area to heat up once again today into the mid to upper 80s. A few 90 degree readings are possible again today. Stayed close to guidance on lows tonight with precipitation and clouds across the area. Clouds and precipitation will hold for Sunday, so have undercut guidance on the highs with temperatures failing to make 80. .LONG TERM...(Sunday night through Friday) Issued at 430 AM EDT SAT SEP 17 2016 A poorly defined cold front will be in our area as the period starts, and an upper level trough will be approaching from the west. The additional upper level support arriving will be enough to help the front make the jump across the Appalachians on Sunday night. Before this happens, there will still be a potential for showers and thunderstorms in the evening, mainly in the southeast part of the forecast area. Drier air associated with weak ridging will arrive from the west during the night. The surface portion of this ridge breaks down early in the week, while an upper level high remains anchored over the south central conus. A cold front trailing from a large storm system rolling across Canada will drop south, until stalling and dissolving in our area as it reaches the southern edge of the prevailing westerlies aloft and encounters the upper level high at mid week. The front will be moisture starved and is not expected to generate any weather of significance. The upper level high is then forecast to build/transition to the southeast CONUS as surface high pressure passes by to our northeast late in the week. This scenario should keep our weather dry. Each cold front will try to bring a minor influx of drier air, which will allow for seasonably cool early morning temperatures, while sunshine results in warm afternoon readings. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) ISSUED AT 620 AM EDT SAT SEP 17 2016 Expect mainly VFR conditions to prevail through this evening. Winds will increase from the southwest today ahead of an approaching cold front. This front will cross eastern Kentucky tonight, with a round of showers and perhaps a few storms expected. This could bring some temporary reductions in ceilings and visibilities. As the front pushes across the area Sunday, we could be looking at period of MVFR (and perhaps some IFR) conditions immediately behind the front. With the front expected to move very slowly, the restrictions to ceilings may persist through much of Sunday, keeping conditions MVFR or worse. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...KAS LONG TERM...HAL AVIATION...KAS
Area Forecast Discussion
National Weather Service North Platte NE
605 AM CDT SAT SEP 17 2016 .SHORT TERM...(Today and tonight) Issued at 355 AM CDT Sat Sep 17 2016 The main concerns in the short term period centers around rain showers/thunderstorms chances and the potential for strong and/or severe thunderstorms. At the present time satellite imagery shows clear skies and no significant weather occurring across the forecast area. Warmer conditions are expected today, with highs forecast in the lower 80s, about three to eight degrees above normal. Above normal lows are then expected overnight, mid 40s in the far western portion of the forecast area to low to mid 50s in north central NE. Weak 500 hPa height rises will be occurring at the start of the period over western and north central NE as a broad 500 hPa trough will be over the MN Arrowhead Region and far Upper Great Lakes. The upper level trough will deamplify over the next 24 hours as it lifts eastward into the extreme eastern portion of Ontario. In the meantime, a short wave trough is anticipated to move east across south central WY to southwest NE to north central KS by late this evening. This disturbance is expected to provide weak large scale ascent and support convective development as mid-level lapse rates steepen over northeast CO and the NE Panhandle into western NE this afternoon and evening. Meanwhile, broad surface high pressure currently over the Central Plains will move eastward today and a weak lee side trough will develop and deepen near the Front Range. Current thinking is that convective development will be focused in this trough. Wherein modest instability and sufficient moisture will combine with 0-6 km bulk shear generally about 20-35 kts that will be conducive for organized multicells. Of which, moisture looks to be the primary limiting factor and this could be attributable to the amount of moisture being returned northward into the forecast area today. Development is expected to move from northeast CO into the forecast area and/or occur in southwest NE early-mid evening with isolated to scattered coverage expected. Hi-res deterministic guidance, HRRR and flavors of WRF, were in decent agreement at the present time with forecast development shown 21-00Z today. Confidence in development is further increased based on SPC SSEO output from the 00Z cycle today wherein a strong signal appears present over southwest NE and northeast CO for convection. The main risks will be strong winds and hail. Of note, the latest SPC Day 1 Outlook has the southwest quad of the forecast area in a marginal risk area, which seems appropriate if storms can develop given aforementioned vertical wind shear. Ultimately, a strong/severe storm or two could be possible today, and cannot be ruled out. Any development is expected to taper off/diminish in the late evening or move southeast out of the area. After which, quiet conditions are expected. .LONG TERM...(Sunday through Friday) Issued at 355 AM CDT Sat Sep 17 2016 Generally upper level zonal flow overhead with a broad ridge across the southern plains to begin the week. Thermal ridge Sunday across the area with highs into the 80s. A weak cold front will enter the picture on Monday. Models in disagreement on timing the front through the southern part of the CWA. Expect the northern part of the CWA to see about 5 degrees or so drop in temps from Sunday, however less confidence for the area along and south of I80. Forecast is conservative across the south and will continue temps only a couple of degrees cooler, but would not be surprised to see highs a degree or two warmer due to compressional heating ahead of the front. Little moisture to work with and temps aloft stay fairly warm for mid September and expect the passage of the front to be dry with only some passing clouds. Thermal ridge quickly rebuilds for Tuesday with temps expected to go back up. Next upper level trough and sfc frontal passage is expected Wed. Ahead of the front southerly winds will usher in some sfc moisture which will aid in keeping lows very mild Wed morning, only falling into the mid 50s and lower 60s. The return of sfc moisture will result in a chance for precip with the passage of the front, mainly in the east on Wed. The trough will continue to push to the north with another trough to dig to the west. The ridge will get shoved east with more SW flow aloft. This will return some upper level moisture and bring a better chance precip with several disturbances. Pops are low at this time as model differences exist with waves. Expect at least more mid and high clouds. Pending cloud cover which could keep temps lower during the day, mos guidance still keeps afternoon highs fairly close to seasonal averages or warmer. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) Issued at 600 AM CDT Sat Sep 17 2016 VFR category prevails across western and north central NE at the present time and VFR are expected to continue through the aviation forecast time period. Clouds are expected to increase across southwest Nebraska in the afternoon with broken ceilings possible, wherein cloud bases around 7 kft to 10 kft are expected. Isolated to scattered thunderstorms are possible across southwest NE in the afternoon and evening, however, best chances are expected to be west and south of KLBF. Therefore showers/thunderstorms were not included in the KLBF TAF at this time given low confidence and expected coverage. Winds will be southwest and peak between 10 and 15 kts. Chances for precipitation then diminish in the mid to late evening. && .LBF Watches/Warnings/Advisories... None. && $$ SHORT TERM...ET LONG TERM...Masek AVIATION...ET
Area Forecast Discussion
National Weather Service Lubbock TX
610 AM CDT SAT SEP 17 2016 .AVIATION... LBB will start the morning with TSRA close and on the terminal while PVW and CDS are under VFR conditions. Conditions at LBB should improve by 12Z and remain VFR into the early afternoon at least. TSRA will be possible at all three terminals this afternoon and evening, however coverage and timing are highly uncertain. Due to high uncertainty TSRA will be kept out of this TAF cycle. MVFR CIGS will be possible towards the end of this TAF cycle tomorrow morning. && .PREV DISCUSSION... /issued 303 AM CDT SAT SEP 17 2016/ SHORT TERM... Thunderstorms have started to develop along a weak surface boundary/front across our southwestern zones. The boundary is hardly discernible using surface obs as winds are light and vary variable, but the boundary does show up on radar. This convective development coincides with an upper level jet streak moving into the FA as shown by WV imagery and a LLJ that has developed over the past few hours. This activity is being pushed east northeastward by the mid and upper level flow. The only model to pick up on this activity well is the 00Z run of the TTU-WRF and keeps this activity going till after sunrise before dissipating across our northeastern counties. The 06Z run of the HRRR also shows this activity, but has it developed further north than it currently is and pushes the convection southeastward instead of northeastward and dissipated the convection fairly quickly. Given the persistent and even strengthening LLJ, it can be believed that convection could be sustained at least for the next several hours. Now for the big question: what will happen from later this morning into tonight? Models have each given their thoughts on the matter, and each thought is different from the other models. Given that the higher res mesoscale models have performed the best recently, they will be weighted more heavily in the forecast. An upper level shortwave currently over northeastern UT/southwestern WY should develop a lee trof by the late morning in CO, during which time convection is progged to develop over the higher terrain of NM. The terrain induced convection has the potential to push eastward into the FA possibly merging with convection along the lee trof to form a QLCS. The QLCS may push into our northern zones of the FA later this evening , but current guidance keeps it northward in the TX and OK Panhandles. For now chance PoPs for this evening will remain unchanged due to the uncertainty of where the QLCS will go. Aldrich LONG TERM... The long term will serve up warm and dry weather as a change in the upper pattern takes place early in the period. Upper level ridging will build over the region Sunday with the center over or near the region through Tuesday. Wednesday will see the ridge shift to the east as an upper trough develops over the western CONUS. It is looking more and more like energy from this trough will remain well west of the forecast area, a trend noted in the last several model runs. Really cannot pick out a period where thunderstorm chances would be high enough to include in the forecast, and will thus remove mention through Friday. Have again trended temperatures toward MOS for Monday and Tuesday, slightly higher than the model blend. Otherwise, the blend looks fine. && .LUB Watches/Warnings/Advisories... None. && $$ 51
Area Forecast Discussion
National Weather Service Paducah KY
657 AM CDT SAT SEP 17 2016 .SHORT TERM...(Today through Monday night) Issued at 344 AM CDT Sat Sep 17 2016 Current radar trends indicate showers and isolated thunderstorms moving across the region faster than previously forecast. The latest HRRR and ECMWF seem to have a decent handle on the timing. This lends itself to a quicker end to precip across the region, with far western portions of the PAH forecast area precipitation free by mid day, and all but far eastern portions dry by late afternoon. Adjusted precipitation chances to reflect this trend, and removed precipitation chances completely for late tonight and Sunday. Temperatures will cool down just a little behind the cold front to near seasonal readings. High pressure will shift across our region for Sunday night into Monday night. This will keep our region dry, and winds will shift back to the south. Temperatures will warm back up to above seasonal readings with highs Monday in the middle to upper 80s, and lows Monday night middle to upper 60s. .LONG TERM...(Tuesday through Friday) Issued at 344 AM CDT Sat Sep 17 2016 Above average confidence through most of the period, then average to below average at the very end due to model inconsistencies. Very little to discuss and very few changes synoptically in the long term period, especially if the ECMWF pans out. High pressure at the surface and ridging aloft is forecast through the long term period producing dry, warm, and humid conditions. On Friday the GFS weakens and suppresses the upper ridge southward allowing a back door cold front to sag into the far northern and northeastern sections of our CWA and cranks out a bit of QPF in the process. During the same time frame the ECMWF keeps the ridge stronger and keeps all frontal boundaries and precipitation chances well to our north. Will go with the more consistent ECMWF solution for now and keep it dry every period. Temperatures will remain at or above normal through the period. && .AVIATION... Issued at 657 AM CDT Sat Sep 17 2016 MVFR to IFR cigs with VFR vsbys expected through the day ahead of a cold front. Showers at KEVV/KOWB will move east of sites by 15z. Isolated showers and storms possible through the day but chances not high enough to include in TAFs. South to southwest winds at 3 to 7 kts will become northwest around 18z at KCGI/KOWB, and between 22z-02z at KEVV/KOWB. Conditions will become VFR this evening, with MVFR vsbys possible after 08z. && .PAH Watches/Warnings/Advisories... IL...None. MO...None. IN...None. KY...None. && $$ SHORT TERM...RST LONG TERM...JP AVIATION...RST
Area Forecast Discussion
National Weather Service Charleston WV
1203 PM EDT SAT SEP 17 2016 .SYNOPSIS... A cold front moves slowly across the area tonight and Sunday...with widespread showers and scattered thunderstorms. High pressure early next week brings only slightly cooler weather. && .NEAR TERM /THROUGH TONIGHT/... As of 1100 AM Saturday... Per hi res models and satellite/radar trends...have adjusted pops remainder of today to only slight chance of an afternoon shower or storm. Have also lowered sky cover somewhat with brief mid level dry intrusion ahead of approaching front tonight. As of 638 AM Saturday... Made a whole bunch of edits to the POPs based on current radar trends...the HRRR...and the RAP models. In the end...line of showers with isolated storms will move east slowly this morning with the boundary...dissipate into the afternoon with only low chances across the area into tonight...and redevelop later tonight as the cold front approaches. No POPs below 15 for the near term however. As of 255 AM Saturday... Showers developing along the warm front this morning...expected to make a slow drift eastward through the remainder of the morning hours. Coverage should gradually increase during this time frame as well. Once the warm front exits...a lull in the activity is expected...largely until the cold front pushes into the middle Ohio Valley. CWA will not be devoid of POPs in this transition period. In the meantime...southwest flow aloft will be on the increase...with upper level support aiding in the development of the convection later today in the far northwestern zones. To the northwest...there will be a significant increase in the low level flow with a 45kt 850mb jet setting up over northern Ohio. With that...SPC includes the southeast Ohio counties in a marginal risk of severe weather today for wind. This is ahead of an upper trough embedded within the aforementioned southwest flow aloft. Towards the 12Z Sunday time frame...expecting an increase in the low level frontogenesis into the Tug Fork Valley...so ramped up POPs sharply towards the transition to the short term forecast. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... As of 345 AM Saturday... A good soaking rain is on tap for Sunday. Weak cold front and associated shortwave will slowly press through the region. Moisture advection in southwesterly flow will push PWATs near or slightly above 1.75 inches. This is about 2 standard deviations above normal...and although instability and forcing will be weak there should at least be enough lift to develop some embedded thunderstorms. Not thinking we will see flash flooding issues since we have been very dry the past several weeks. However...if a few storms could train over the same area then some minor flash flooding could be possible and as such...WPC has highlighted our area for a marginal risk for excessive rainfall. High pressure and cooler air moves in for Monday...but with upper trough overhead and northwesterly flow giving us some orographic accent...there should be enough to kick off some isolated showers in the Eastern Mountains. Other than that skies will clear Monday night and make for a cool night where it may actually feel a bit like Fall. Radiational valley fog will likely be widespread overnight Monday and into Tuesday morning. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 150 PM Friday... The long term is overall a quiet period, starting out with high pressure in control. Both GFS and ECMWF show a weakening front approaching Tuesday, but with dry air in place neither are showing much in the way of QPF. Kept the forecast dry. High pressure settles back in to end the work week. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... As of 11 AM Saturday... Til 00Z... Warm front with scattered showers quickly exiting area to the north at 15Z. Thereafter...a brief mid level dry intrusion will limit afternoon convection to isolated...except over southeast Ohio where a band of widespread showers and a few thunderstorms will arrive well ahead of a cold front after 22Z. Thus...have removed mention of showers and storms from major TAF sites this period. Maintain VFR sct-bkn 4500-8000 foot AGL clouds this afternoon...except MVFR where widespread showers arrive over portions of Southeast Ohio late this afternoon and evening. South winds 6 to 12 kts. After 00Z... The band of widespread showers and scattered thunderstorms well ahead of a cold front...will slowly spread eastward across the area with a slow moving strong upper level disturbance...reaching a CKB-CRW-JKL line 10-12z. The cold front itself will lag far behind the advancing so light south winds around 5 kts will can be expected. VFR ceilings will lower to IFR in rain and fog as the band of showers and storms arrive. Thus...PKB and HTS will lower to IFR by 07Z...CKB and CRW by 12z. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing of band of convection tonight may be slower than currently forecast. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02 EDT 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 CRW CONSISTENCY M M H H H H H H H H H M HTS CONSISTENCY H H H H H H H H H H H M BKW CONSISTENCY H M M H H H H H H H H M EKN CONSISTENCY H H M L M H H H H M M M PKB CONSISTENCY M M H H H H H H H H H M CKB CONSISTENCY H M M L M H H H H M M M AFTER 12Z SUNDAY... IFR possible in showers/storms with cold front this weekend. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...JMV/MPK/26 NEAR TERM...26 SHORT TERM...MPK LONG TERM...MZ AVIATION...JMV/26
Area Forecast Discussion
National Weather Service Blacksburg VA
958 AM EDT Sat Sep 17 2016 .SYNOPSIS... High pressure, both at the surface and aloft, will weaken and shift east of the region through Sunday. An upper trough and associated cold front will move into the region Sunday, taking until Monday to move through the Piedmont. High pressure will build over the region by Tuesday and linger through the end of next week. && .NEAR TERM /THROUGH TONIGHT/... As of 950 AM EDT Saturday... Models are backing off of mountain showers through this afternoon. Morning showers over the Ohio Valley are tracking to the northwest and there is no evidence that any will develop in their wake. We will keep a small chance across SE WV late this afternoon for the possibly of scattered showers forming from any outflow boundaries during peak heating. The best chance for widespread showers to enter the mountains will come Sunday morning as a cold front approaches the area. As of 400 AM EDT Saturday... High pressure off the northern Mid-Atlantic coast will shift east in response to an upstream trough/cold front approaching from the Midwest. However, it will not do so soon enough to prevent another mostly cloudy, relatively cool/mild day compared to most days this month, which have been well above normal. The low clouds are expected to erode across the Piedmont and west of the Alleghany front by afternoon and in most areas by evening as the upper trough/front continue to move into the region from the west. However, this will not be soon enough to allow temperatures to warm yet back to the pre-wedge levels we saw much of this past week. Precipitation is expected to be scarce again today. Most synoptic and short-range models indicate that the best and initial dynamics associated with the upper trough will move northeast toward the Great Lakes/eastern OH valley. Showers and a few thunderstorms will likely approach the northwest border of the CWA late in the afternoon/evening but probably stop short of spreading into much, if any, of the RNK CWA. The HRRR and NCEP WRF show little to no precipitation spreading into the RNK CWA this afternoon/evening. The first wave will go by overnight leaving us with just mid/high clouds and little precipitation. Therefore, have confined pops to slight chance/low chance along the western border to near zero along and east of the Blue Ridge. Mentionable pops have generally been confined to just the western most tier of counties, with the highest pops from KBLF to west of KLWB. As noted above, an increase in temperatures is expected today, but should stop short of the 10F above normal readings we have seen most days this month. Max temperatures today will be entirely dependent on when the low clouds diminish. If this occurs late morning, as opposed to the afternoon, advertised readings may be too cool. Have leaned toward the cooler GFS gridded temperatures as it seem to have the best depiction of the wedge air mass. Minimum temperatures Sunday morning will be well above normal, mostly in the 60s. We should be seeing lows in the 40s and 50s by now! && .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... As of 145 AM EDT Saturday... The cold front that is expected to remain to our west today and tonight, will make gradual headway eastward into and through the region Sunday into Sunday night. Anticipate an increase in the coverage of showers from west to east as the day progresses, especially by the afternoon hours. Chances will be greatest in the east during the evening and overnight hours. Model forecast instability factors are not substantial, nor are they on the low side. The forecast will reflect a slight chance for thunderstorms by mid-day Sunday continuing only into the early Sunday evening hours. The probability of showers will be in the likely category in areas closest to the front. By Monday morning, the front will have just exited, or be on the far eastern edge of the forecast area. Slow progression eastward is still forecast for this feature. It is expected to still be in close enough proximity to allow for isolated to scattered showers across eastern parts of the area. Forecast instability factors are more impressive for thunderstorm development during the peak heating of the day, especially the far eastern parts of the area by the late afternoon. Other showers are forecast across the preferred upslope regions of southeast West Virginia during the morning hours thanks to residual low level moisture and an increasing upslope, northwest flow in that region in the wake of the cold front. Surface high pressure is expected to build across the Ohio Valley By Monday night, and take on a west-east orientation with its axis reaching the Delmarva peninsula by Tuesday night. Aloft, an upper ridge is also expected to develop over the Tennessee and Ohio Valleys. As geopotential heights build across the region, so too will 850 mb temperatures. Late night and early morning fog will be common through the period, especially Sunday night and Monday night. Despite the passage of a cold front, temperatures during this portion of the forecast will continue to remain above normal for this time of the year by five to ten degrees. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 330 PM EDT Friday... High pressure, both surface and aloft, is expected to dominate the region much of this period. An upper level trough is progged to become a closed low over the southeastern states as it begins to interact with Tropical Storm Julia, drifting west again back toward the southeast U.S. coast. An upper level ridge will build east from the Gulf States Wednesday and center itself over the Carolinas by next weekend. This ridge could take Julia westward across Florida and into the Gulf of Mexico. For the immediate area, this ridge will bring several days of warmer than normal temperatures and little chances for rain. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... As of 735 AM EDT Saturday... Weak wedge continues to hold across the area with widespread MVFR to high end IFR cigs in place across much of the CWA at this time. Expect ceilings to improve to MVFR in the 14Z-16Z time frame, then to VFR during in the 17Z-18Z time frame as the wedge erodes from both the west and east ends. Do not expect the wedge to hold as well as it did Friday as upstream trough/front encroaches on the departing wedge. Latest model runs, including HRRR and NCEP WRF, show little in the way of meaningful precipitation reaching the CWA today, so have not advertised. Feel that this will remain west to northwest of the CWA, closer to the upper dynamics with an approaching short wave and not be able to penetrate the weakening wedge air mass to any appreciable degree, at least not at the TAF sites. Perhaps in Smyth/Tazewell area, so may need to watch KBLF late in the day. With the wedge gone overnight/Sunday morning, do not expect a repeat of the low clouds and MVFR-IFR cigs. However, mid/high clouds will spread into the region from upstream. These should be mostly VFR cigs. The problem Sunday morning evolves east of the Alleghany front, where cloud cover may be too sparse much of the night to prevent ground fog development. Confidence is not high enough to advertise IFR-LIFR conditions in fog Sunday morning, but this is a possibility at KBCB and KLYH for sure. Showers and any thunderstorms will hold off until well after this valid TAF period. Winds will remain mostly E-SE through the period at speeds of 5-7kts with low end gusts possible at KBLF until late afternoon, especially this morning, however. Medium confidence in cigs through the TAF valid period. Medium to high confidence in vsbys through the TAF valid period. Medium to high confidence in wind speed/direction through the TAF valid period. Extended aviation discussion... Approaching cold front will move into the region Sunday, but take until Monday to move completely east of the CWA. Wedge front dissipates. Sub-VFR cigs will be possible Sunday as a result of increasing showers and isold thunderstorms during the afternoon, with patchy fog/low clouds in the morning. High pressure will build back into the region early in the week, so after the front exits the area Monday morning, expect most VFR conditions for several days until late week. The exception will be late night/early morning fog/low clouds, more likely toward the end of the week as moisture begins to return around the departing surface high. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...RAB NEAR TERM...RAB/RCS SHORT TERM...DS LONG TERM...RCS AVIATION...RAB
Area Forecast Discussion
National Weather Service SAN ANGELO TX
613 AM CDT SAT SEP 17 2016 .AVIATION... /12Z TAFS/ VFR conditions should prevail across West Central Texas terminals through the period. However, scattered showers and thunderstorms will again be possible. Latest model data suggests the San Angelo (KSJT) has the best chances from seeing one of these storms, although the odds remain low. Given the low odds, will not insert in the forecast at this point but continue to monitor and see if the model trend continues. Winds will remain light, but mainly out of the south and southeast. && .PREV DISCUSSION... /issued 325 AM CDT SAT SEP 17 2016/ SHORT TERM... (Today and Tonight) Bulk of the evening convection has now dissipated across West Central Texas early this morning. Models have struggled to handle the convection over the last few days across West Central Texas, with the HRRR handling the short term better than the other models. Thus, will lean towards its solution as a first guess to start the forecast, with scattered convection developing late this afternoon across the western portions of the area, mainly west of an Abilene to San Angelo line. Like has happened the last few days, expect this convection to spread east across the area into the evening hours. As for temperatures, will not deviate much from what we have seen the last few days. Readings have managed to climb into the upper 80s and lower 90s across the area, and should be in the same range today. LONG TERM... (Sunday through Friday) On Sunday, an upper level ridge will be centered across South Texas/northern Mexico. A subtle upper level shortwave trough is forecast to swing across North Texas which may aid in the development of scattered showers and thunderstorms Sunday afternoon, mainly across the eastern half of the forecast area. Any shower and thunderstorm activity should dissipate by early evening. High temperatures will be well above seasonal normals, in the low to mid 90s. An upper level ridge will dominate the weather across West Central Texas through much of the upcoming work week. Generally dry conditions are expected along with above normal temperatures. Highs through the first part of the work week will be in the low to mid 90s, with overnight lows in the upper 60s to lower 70s. The center of the upper level ridge is then forecast to shift toward the South Atlantic states, which will result in slightly cooler temperatures for the second half of the work week. Expect highs mainly in the upper 80s to lower 90s, with overnight lows in the in the mid to upper 60s. The next upper level trough is forecast to approach the area next weekend, possibly bringing an increasing chance of showers and thunderstorms. && .PRELIMINARY POINT TEMPS/POPS... Abilene 90 69 93 72 / 30 20 20 5 San Angelo 92 69 95 71 / 30 20 10 5 Junction 91 70 95 71 / 20 10 20 5 Brownwood 91 70 93 70 / 20 20 20 5 Sweetwater 89 69 91 71 / 30 20 10 5 Ozona 91 69 93 70 / 20 10 5 5 && .SJT Watches/Warnings/Advisories... None. && $$ 07/99/07
Area Forecast Discussion...UPDATED
National Weather Service Tallahassee FL
1049 AM EDT SAT SEP 17 2016 .NEAR TERM [Through Today]... The 8 am EDT regional surface analysis showed a ridge along the Piedmont, and a weak trough (oriented north to south) centered near Apalachicola. Vapor imagery and upper air data showed a weak trough, an MCV from a large cluster of earlier thunderstorms, centered along the LA coast. Higher heights were over east FL, along with progressively drier air (from west to east). The RAP analysis showed weak Q-G forcing over the western half of our forecast area, and there were scattered light showers and isolated thunderstorms, as well as abundant clouds in this region. Our normally-reliable local CAM ensemble, as well as the NCAR CAM ensemble, are drier than the rest of the NWP guidance, though their PoP distribution matches the others. Why this is is unclear; perhaps the cloud cover will mute the sea breeze forcing somewhat? Nevertheless, this guidance has not initialized all that well, and there is plenty of deep layer moisture to support convection, though MLCAPE profiles are quite skinny (i.e. rather low CAPE). Given these conflicting factors, we think it best to just leave the previous forecasters` PoP/QPF forecasts alone, sticking with high PoPs (50% or more) west of Tallahassee and Albany. The only slight change we made was to nudge this afternoon`s temperatures down a few degrees across much of the region based on the extensive clouds. && .PREV DISCUSSION [651 AM EDT]... .SHORT TERM [Tonight Through Monday]... Deep layer moisture will continue to increase through Sunday ahead of a mid to upper level trough. The latest MOS PoP guidance including MAV and local ensemble of CAMs are now in fairly good agreement showing portions of our CWA with good to likely chance for convection Sunday. Have increased PoPs mainly across our SE AL and Florida zones but have undercut guidance for now. The trough is forecast to sharpen as it passes over and just to our east Sunday night through Monday. A much drier airmass will filter in from the northwest in its wake. PoPs Monday will be tapered 20% north to 30-40% south. Max temps will be around 90 Sunday and the lower 90s Monday. Lows will be in the lower 70s. .LONG TERM [Monday Night Through Saturday]... As the upper trough slides off the eastern seaboard Monday night, deep layer ridging builds in and quickly noses eastward to the Mid-Atlantic states. The latest EURO has now come in line with the GFS solution showing what will likely be the remnant of Julia getting trapped under the ridge moving westward and inland across SE GA/NE FL during the middle of next week. The moisture associated with this feature would likely spread over our CWA increasing or chances for convection. Still not sold on this solution so PoPs will remain in the slight to chance range (20-40%) through most of the period. Highs will be in the low to mid 90s and lows in the low 70s to upper 60s. .AVIATION [Through 12Z Sunday]... MVFR ceilings are scattered about the region this morning. Restrictions have only been included at ECP and DHN as they are most likely to be impacted. VFR will prevail at all terminals outside of showers and thunderstorms by mid-morning. Storms are likely at ECP and DHN this afternoon. .MARINE... The pressure gradient will remain quite weak for the next several days with light winds and low seas. .FIRE WEATHER... Hazardous fire weather conditions are not expected over the next several days. .HYDROLOGY... The local rivers were below their "action" stages, and are expected to remain so for the next several days. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 88 73 91 74 93 / 40 20 50 30 30 Panama City 84 76 86 76 88 / 60 20 40 40 30 Dothan 86 71 90 72 92 / 50 20 40 30 20 Albany 91 71 91 72 93 / 20 20 30 30 20 Valdosta 91 70 91 72 92 / 20 10 30 30 30 Cross City 89 72 89 73 90 / 30 20 50 30 40 Apalachicola 84 75 86 76 87 / 50 20 40 30 40 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...Fournier SHORT TERM...Barry LONG TERM...Barry AVIATION...Harrigan MARINE...Barry FIRE WEATHER...Harrigan HYDROLOGY...Fournier
Area Forecast Discussion
National Weather Service Columbia SC
557 PM EDT SAT SEP 17 2016 .SYNOPSIS... High pressure ridging into the forecast area from the north will weaken ahead of an approaching cold front. The weak front will move through the area Late Sunday night and Monday. Julia will linger off the southeast coast but most of its associated moisture will remain east of the forecast area through Monday. && .NEAR TERM /THROUGH SUNDAY/... Update: Mostly clear skies prevailed across The Midlands and CSRA this evening. Expect stratus and fog to redevelop overnight with deep low level moisture and light winds. No changes made to the exsiting forecast. Surface high pressure will continue to ridge into the Carolinas and Georgia from the north with Julia meandering off the coast today into tonight. A mid-level capping inversion will limit convective development this afternoon. Scattered cumulus are expected from daytime heating but are not likely to develop into showers. The HRRR does show isolated showers moving inland from the coast but dissipating before they reach the forecast area. Tonight, upper level ridging over the southeastern states will retreat to the southwest as a trough moves into the Mississippi River Valley. Lows tonight will be in the upper 60s to lower 70s. Models are suggesting deeper moisture and lighter low level winds. It is likely that stratus and fog will develop again tonight through late Sunday morning. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/... The models show h5 troughing moving into the forecast area Sunday and Sunday night with the trough over the region Monday. Difluent h5 heights are depicted ahead of the trough Sunday and Sunday night and a lead shortwave trough may move into the area Sunday. The models are consistent with shallow moisture through early Sunday. The shallow moisture and nocturnal cooling with light wind should result in areas of fog during the early morning hours Sunday. Moisture may become deep enough especially in the west part for showers and thunderstorms Sunday afternoon. The NAM MOS pops have trended upward and we have forecasted chance pops mainly in the west part. There should be increased instability Sunday night and Monday associated with the upper trough. However, low- level convergence along the weak front should remain weak because of the northwest flow on the backside of the offshore low. There is high spread with the pop guidance. The GFS, NAM, ECMWF, and EKD MOS have pops of 10 to 60 percent with the NAM highest. Kept pops in the chance category because of the expected weak low- level convergence. The NAM and GFS have surface-based LI values -4 to -8 with the GFS most unstable. Followed the guidance consensus for the temperature forecast. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... There is low confidence during the medium-range period because of model inconsistency. Previous runs of the GFS have displayed upper ridging more dominate. The 12z run had an h5 cut-off low over the area Tuesday through Friday with the upper feature beginning to fill Friday. The latest run showed considerable wrap-around moisture associated with low pressure near the coast with moisture in an onshore flow continuing during much of the rest of the period. The GFS MOS pops have increased to around 40 percent. The GFS ensemble mean previously was 10 to 20 percent Tuesday and Wednesday, and 20 to 30 percent during the rest of the period. The GFS MOS high temperatures have also lowered. We have increased pops and lower temperatures but not to quite the degree of the latest guidance based on the inconsistency. Previous runs of the ECMWF also indicated most of the moisture staying east and south of the forecast area. && .AVIATION /22Z SATURDAY THROUGH THURSDAY/... No convection is expected to impact the terminals today. Models have been consistent and are in good agreement indicating restrictions late tonight and into Sunday morning. Deeper moisture and lighter low level winds will support fog development and low stratus. MVFR/IFR ceilings and visibilities likely after 08z tonight. Higher confidence in LIFR early Sunday morning, included in TAFS through mid Sunday morning. EXTENDED AVIATION OUTLOOK...Early morning fog and stratus remain a possibility through the period with a chance of mainly afternoon/evening thunderstorms early next week. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
Area Forecast Discussion
National Weather Service Dodge City KS
342 PM CDT SAT SEP 17 2016 ...Updated short term and long term discussion... .SHORT TERM...(This evening through Sunday) Issued at 335 PM CDT Sat Sep 17 2016 Shortwave trough was moving east southeast out of southern Wyoming and northern Colorado this afternoon. Fairly cool mid level temperatures around -15c associated with the wave is helping destabilize the mid levels with clusters of strong to severe thunderstorms breaking out over northeast and east central Colorado. Farther southwest, convection was also breaking out over the Raton Mesa. Instability axis has been situated over eastern Colorado and south into far southwest Kansas and down through west Texas. Better Bulk Shear values are also confined to the TX Panhandle with marginal shear farther north. Best chance for severe should be over the far southwest where parameters come together better. A little more uncertainty as to how long convection over northeast Colorado is sustained as it moves out into northwest and north central Kansas this evening. Most model solutions have that convection dying out this evening while the HRRR tends to sustain it all the way through central Kansas. Storms could stay organized across southwest into south central Kansas this evening and may need to increase pops across that area. Things quiet down fairly quickly after midnight as the short wave trough moves east out of the area. Sunday will be mainly sunny as upper level ridging begins to build over the central Plains. With increasing thickness values and weak low level downslope, high temperatures should be a few degrees warmer than today, around 85 to 90. .LONG TERM...(Sunday night through Saturday) Issued at 335 PM CDT Sat Sep 17 2016 Upper level ridging builds across the southern CONUS during the early part of next week with the upper level westerly flow shunted northward into the northern Plains and southern Canada. A shortwave moving east along the US/Canadian border on Monday will push a cold front south into the central Plains, possibly as far south as I-70, on Monday afternoon. With a drier airmass in place by then, the potential for storms looks minimal. Daytime high temperatures should be up into the 90s during the first part of the week. By mid week. the upper high gets suppressed a little farther south while upper level southwesterly flow increases over the central Plains. A shortwave lifts out over the central Plains on Wednesday. There is some potential for perhaps some nocturnal storms across western Kansas early Wednesday morning. This wave could push a boundary into western Kansas during the day, providing focus for more additional storm development. Temperatures should be cooling off back into the 80s later in the week. && .AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon) Issued at 1217 PM CDT Sat Sep 17 2016 Lingering scattered low clouds around Garden City should dissipate rapidly at the beginning of the period. VFR conditions should prevail through much of the period. Widely scattered to isolated thunderstorms are expected to develop over eastern Colorado this afternoon and move into western Kansas by late afternoon or early evening. Thinking that the Garden City terminal will have the best chance for thunderstorm impacts and have included a tempo group to reflect that this evening. Less confident for thunderstorms around Dodge City and Hays but will keep VCTS for a time at those locations this evening. && .PRELIMINARY POINT TEMPS/POPS... DDC 58 87 61 93 / 30 0 0 0 GCK 55 87 57 91 / 40 0 0 0 EHA 55 88 58 92 / 40 0 0 0 LBL 57 89 60 92 / 40 0 0 0 HYS 57 87 61 91 / 30 0 0 0 P28 60 86 66 93 / 30 10 0 0 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Gerard LONG TERM...Gerard AVIATION...Gerard
Area Forecast Discussion
National Weather Service Indianapolis IN
430 PM EDT SAT SEP 17 2016 .UPDATE... The Aviation section has been updated below. && .SYNOPSIS... Issued at 147 PM EDT Sat Sep 17 2016 A cold front will sweep across central Indiana tonight and push cooler and drier air into the state. Dry weather is expected in the wake of the front for the second half of the weekend as High pressure builds across the Ohio Valley. The high will keep dry weather in place at least through Tuesday and it slowly moves across Indiana to the Kentucky and Tennessee. Another frontal system could bring more rain late in the week. Tempertures will remain above average. && .NEAR TERM /Tonight/... Issued at 147 PM EDT Sat Sep 17 2016 Surface analysis early this afternoon shows a broad trough of low pressure across Indiana. A cold front was found over NW Illinois...and Central Wisconsin. Radar shows rain showers amid the broad trough exiting central Indiana...although a few weak showers were trying to develop within the troughy flow. a key point can be seen within the water vapor imagery...were drying and subsidence over Illinois was building east into Indiana...helping to push a plume of moisture out of the state. Main forecast challenge tonight will be ending precip chances and dealing with temperatures. This afternoon...the HRRR continues to suggest convective development ahead of the cold front. It appears a bit over aggressive. Still with forecast soundings showing reachable convective temps...and isolated shra cannot be rules out. Thus will keep some low chance pops in through 23z...as once heating is lost precip threat will be over as subsidence will have pushed all moisture well east of Indiana. Forecast soundings and Time heights show excellent drying and subsidence within the column through tonight as High pressure over the plains builds eastward in the wake of the passing Cold front. Time heights do show some lingering lower level moisture through the night. Given the recent rains...light winds and limited mixing...we will expect at least some patchy fog overnight as models suggest dew point depressions of 1F or less. Given the weak cold air advection...will trend lows at or slightly below mavmos. && .SHORT TERM /Sunday through Tuesday/... Issued at 147 PM EDT Sat Sep 17 2016 Main focus during this period will be temps. Aloft the models are suggesting a broad trough passing across the state on Sunday. however with high pressure in place at the surface...along with dry continental flow...no rain will be expected wit this feature. Forecast soundings remain dry as do the time height sections. Convective temps in the mid and upper 70s should result in the sct cu...but a mid level inversion should prevent any growth. Thus will trend toward a partly cloudy sky and use a blend on HIghs. Upper flow on Sunday night through tuesday suggests upper ridging evolving to mainly a zonal flow by Tuesday. Forecast soundings remain very dry as do the Time height sections. Meanwhile at the surface...large and broad high pressure is expected to settle across the Ohio valley. Furthermore...mid levels show good subsidence through the period and strong high pressure building through the Mississippi river valley. Thus will trend toward partly cloudy days and mostly clear nights and a blend on temps. && .LONG TERM /Tuesday night through Saturday/... Issued at 232 PM EDT Sat Sep 17 2016 The long term will generally be controlled by a broad upper ridge covering much of the central U.S. This will bring warmer than normal temperatures and dry weather to the area. By the end of the week a frontal system could approach, but the timing on this is still very uncertain. Generally accepted the initialization of slight chance pops coming in starting Friday night. Changes were made to increase high temperatures from the initialization under the upper ridging and southwesterly component flow from Thursday on. && .AVIATION /Discussion for 17/21z TAFs/... Issued at 430 PM EDT Sat Sep 17 2016 Removed VCSH mention and raised conditions to VFR at IND per obs. Previous discussion follows. Issued at 108 PM EDT Sat Sep 17 2016 Off and on MVFR ceilings possible over the next few hours. A few showers will still be around but for the most part sites should be dry and will leave out any mention beyond vicinity. Then overnight expect some fog to develop, especially in areas that saw the most rainfall this morning. Will go with the lowest conditions at KBMG with 1/2sm, 1sm at KIND and KHUF and stick with MVFR at KLAF. Winds through the rest of the day should be 3-8 kts out of 220-270, with light and variable winds overnight. && .IND Watches/Warnings/Advisories...NONE. && $$ SYNOPSIS...PUMA NEAR TERM...PUMA SHORT TERM...PUMA LONG TERM...CP AVIATION...CP/NIELD
Area Forecast Discussion
National Weather Service Morristown TN
251 PM EDT SAT SEP 17 2016 .SHORT TERM (This Afternoon through Sunday)... Another hot and dry day across the area with a cold front located back to the west near the Mississippi River. Current water vapor imagery and RAP upper air analysis indicates an upper level trough moving into the Great Lakes region. Radar and satellite imagery shows an area of showers/storms across Kentucky stretching southward into North Alabama. Expect this line of shower/storms will weaken as they continue to move to the northeast. Surface dewpoints across the region are in the upper 50s to low 60s with PW values in the 1.3-1.6 inch range with the higher values across the Plateau. As for the remainder of the afternoon, expect the best chance for showers/storms will be across the Plateau where the best moisture values are. The 850 mb jet will increase slightly late tonight into tomorrow morning and expect coverage will begin to increase during this timeframe. Low level cloud cover and continued southerly flow will keep temperatures up tonight into the mid 60s to low 70s. Widespread cloud cover and precipitation is expected tomorrow ahead of the advancing cold front. The widespread cloud cover should keep high temperatures in the upper 70s to low 80s and reduced highs from the previous forecast by about 5 degrees or so. PW values will increase into the 1.7-2.0 inch range during the day tomorrow. These values are well into the 99th percentile for mid-September. Therefore, this will be the best chance for rain throughout the next 7 days. As for rainfall amounts, it looks as though 0.50-0.75 inches with some locations possibly up to an inch. This should help briefly with the ongoing drought conditions. .LONG TERM (Sunday Night through Saturday)... Front will finally push through the rest of the area Monday evening and shower/thunderstorm chances will quickly diminish behind the front from west to east. Not only do the rain chances go away quickly, but the cooler temperatures will also quickly go away as well. We will likely see temps climb back towards 90 degrees in many locations by the middle of the week. Some of the models want to generate light QPF at various times during the week with some moisture in the area... But have gone ahead and left mention out of the forecast for now since models have continued to over forecast rainfall chances throughout this summer. Next best rain chances will likely hold off until another frontal boundary moves towards the area next weekend. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 71 85 69 89 / 50 60 30 10 Knoxville McGhee Tyson Airport, TN 70 82 66 85 / 50 60 30 10 Oak Ridge, TN 69 82 67 86 / 60 70 30 10 Tri Cities Airport, TN 65 79 63 83 / 20 60 40 10 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...None. TN...None. VA...None. && $$ MA/ABM
Area Forecast Discussion
National Weather Service Paducah KY
241 PM CDT SAT SEP 17 2016 .SHORT TERM...(Tonight through Monday night) Issued at 241 PM CDT Sat Sep 17 2016 Radar pretty quiet. Only spotty light rain/showers since mid morning. Little activity currently. Will maintain a very low chance PoP into the early evening over the east 2/3 of the area. RAP shows limited elevated instability, thus will keep slight chance TSRA. But overall, not much expected. Next system will be a s/wv moving from the central Plains to the TN Valley Sunday/Sunday evening. Most of the moisture stays to our south, so dry forecast for now. Dry weather will continue Sunday night through Monday night as well. In the wake of the s/wv, weak high pressure will be in control. Temps will be a blend a MOS blend. We will monitor the fog potential overnight. It is in the forecast. Lows should cross over most areas. Could be low clouds as well. .LONG TERM...(Tuesday through Saturday) Issued at 241 PM CDT Sat Sep 17 2016 Upper level ridge is in place from Wednesday into Friday. On Friday heights fall slightly on all models as upper level low forms over the northern Rockies. By 18z Saturday, the upper level low moves into the northern plains with the GFS having a more negative tilt than other models and ensembles and thus much faster with the cold front. More interesting to us is the moisture pattern forecast. Moisture off the southeast coast early Tuesday is forecast to move under the ridge toward the west and northwest. Although models vary on the details including timing, it looks like the best chance for precipitation will be on Saturday. With the ridge over the area, expect temperatures to be well above normal at least until Friday. Normal highs are in the lower 80s, expect to see upper 80s to lower 90s during that time. && .AVIATION... Issued at 1204 PM CDT Sat Sep 17 2016 Widespread cloud cover over the region this afternoon, though coverage decreases heading NW toward east central MO into west IL. Will maintain low VFR to MVFR cigs. Radar also detects spotty light showers / light rain, and will include in all but the KCGI TAF based on trends. Will scatter out clouds tonight. However from 06z on, there could be some fog to deal with, with near calm winds. Will indicate MVFR vsbys for now. Lower clouds cannot be ruled out either. Taking a minimal mention approach for now so later shifts can adjust accordingly. && .PAH Watches/Warnings/Advisories... IL...None. MO...None. IN...None. KY...None. && $$
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
350 PM EDT SAT SEP 17 2016 .SYNOPSIS... 19Z water vapor and H4 RAP analysis shows broad mid/upper level ridging over the Florida peninsula and eastern gulf this afternoon. The main northern stream flow is well removed to our north and northwest...and this is where it will stay through the remainder of the weekend. The pattern overhead is fairly seasonable for mid- september and will yield a fairly seasonable forecast into the early portion of the the week. 12Z KTBW RAOB sampled a pretty moist column between the surface and 400mb...with lapse rates averaging near moist adiabatic...and a well above average PW value around 2.25". The depth of moisture will once again not hinder the development of convective cells across much of the region...however...the poor lapse rates through a deep layer of the trop will limit the strength of the convective updrafts and potential for any abnormally strong thunderstorms. At the surface...the Florida peninsula resides within a weak pressure gradient between high pressure ridging down from the southeastern states into the eastern Gulf of Mexico...and what is left of tropical depression Julia still spinning off the GA/Carolina coasts. Overall the pattern favors a light east/NE wind flow across our area...however...the weak gradient and strong diurnal heating will force a well-defined sea-breeze and turn winds onshore near the coast for the majority of the afternoon/early evening. 24-48 hours ago...the guidance was showing a decent swath of drier mid-level air arriving over the Nature coast by this afternoon as it pivoted down around the Julia circulation. If now appears as though the driest of this air will be staying just to our north and northeast...and the negative impacts on convection will not be realized to the degree thought earlier. Generally speaking...now that the sea-breezes have becomes fully developed...and we are at peak heating...a scattering of storms will continue to pop into the early evening...with storms tending to come together along the I-75 corridor for the early evening. This is a scenario shown by the HRRR for several runs now. Based on the KTBW RAOB...winds are still light in the mid- levels...but at least today there is a more defined direction...blowing northeast to southwest. Would expect this motion toward the FL west coast to be the majority storm movement once storms become mature and are tall enough to feel this flow aloft. && .SHORT TERM (Tonight through Sunday)... Not a whole lot of change in the synoptic pattern as we head through the overnight and into Sunday compared to what is described above in the synopsis. Storms are likely to line up near the I-75 corridor during the evening as both coast breezes collide. These storms will then fade by 02-03Z and give way to a mostly dry overnight period with slowly clearing skies (at least initially). The light north to northeast flow advertised by the guidance with abundant low level moisture and weak ridging aloft is a favorable setup for some lower stratus development in the pre-dawn hours across NE Florida that will then slowly expand south and west toward the I-4 corridor. We saw a bit of this stratus this past morning...and expect it once again. Latest SREF ensembles are also showing elevated probabilities of lower cigs by dawn. This stratus does not really impact the public forecast as it burns off quickly once the sun rises...but can be quite influential in early morning aviation operations. Similar to today...A dry morning and early afternoon will give way to a building cumulus field and eventually a scattering of showers and storms for the later afternoon and early evening hours. Still waiting for all the 12Z guidance to arrive...but planning on rain chances Sunday afternoon in the 30-40% range for most locations...with perhaps slightly higher numbers down toward Charlotte, Highlands, and Lee counties. High temperatures across the region on Sunday will top out in the upper 80s to around 90. && .MID/LONG TERM... Weak low-level flow to start the week will gradually transition as surface and mid level high pressure looks to become re-established across the region, bringing sustained east to northeast flow into next weekend. There will be subtle changes from day-to-day in regards to atmospheric moisture content but nevertheless PoPs will be in the 40-60% range through the forecast period. As the calendar turns to fall on Thursday, those hoping for some "fall-like" weather can keep dreaming or look much further north as it will continue to feel like summer across the area. Temperatures near 90 each and everyday will continue with dewpoints in the low to mid 70s keeping heat indices near 100. && .AVIATION... VFR for all terminals into the evening hours...other than the potential for a brief thunderstorm. Any restrictions associated with storms will be brief...with storms fading away within a couple hours of sunset this evening. Similar to this morning...areas of lower stratus are likely to migrate south and west into the I-4 corridor around dawn...and possible down as far as KPGD. Will continue to monitor guidance trends and hint at some lower clouds with afternoon TAF package between 09Z- 13Z Sunday. && .MARINE... A quiet and seasonable weather pattern across the eastern Gulf of Mexico through the early portion of next week...as weak high pressure remains in control. Light easterly winds overnight and during the morning hours will give way to developing onshore flow near the coast each afternoon. Isolated to scattered storms can also be expected in the vicinity of the coast late each afternoon and early evening. && .FIRE WEATHER... No significant fire weather concerns are anticipated through the early portion of the week. Generally light flow will remain in place across the Florida peninsula...with abundant low level moisture to keep relative humidity values above critical levels. We are likely to see a daily scattering of afternoon storms...with temperatures and rain potential near normal for this time of year. Fog Potential...Some patchy fog is likely late tonight...especially from I-4 northward across the Nature coast...however...No significant areas of widespread or dense fog are anticipated. && .Preliminary Point Temps/PoPs... TPA 76 89 77 88 / 20 30 20 50 FMY 76 89 76 89 / 20 40 20 60 GIF 75 90 75 89 / 20 40 20 60 SRQ 77 87 76 87 / 20 30 20 50 BKV 74 90 73 89 / 30 40 20 50 SPG 77 89 78 88 / 20 30 20 40 && .TBW Watches/Warnings/Advisories... FL...None. Gulf waters...None. && $$ SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WX...Mroczka MID TERM/LONG TERM/DECISION SUPPORT...McKaughan
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
604 PM CDT SAT SEP 17 2016 .SHORT TERM...(This evening through Sunday) Issued at 251 PM CDT Sat Sep 17 2016 After a round of morning fog, skies have become mostly sunny across the area with highs reaching into the low 80s for most locations. Convection has formed across the high plains of Colorado and far western Kansas, and is slowly making its way eastward. Upper wave associated with this development extends from South Dakota into south central Colorado. Showers have bubbled up over north central Kansas but have dissipated as they move east. For tonight, will need to watch high plains convection, at this time only have some slight chances for thunder mainly south and west of Concordia. HRRR has been bullish at bringing convection to just west of Manhattan, but most remaining guidance keeps CAP in place and with not enough energy to develop elevated convection, dissipates the northern storms and focuses more on the convection rolling out of southern Colorado through the panhandles and through northern Oklahoma. Overnight lows fall into the 50s. On Sunday, not expecting a repeat of the fog given increasing southerly winds through the period, with high temperatures a few degrees warmer today in the middle 80s. .LONG TERM...(Sunday night through Saturday) Issued at 251 PM CDT Sat Sep 17 2016 No major changes or highlights to the previous forecast. Models are in smilier agreement with the main jet stream carrying embedded upper waves across the far northern CONUS while an upper ridge dominates the southern plains and a cut off low rotates off the CA coast. Unlike consensus guidance, the GFS consistently develops a weak vort max from southern OK through the Great Lakes region Sunday night. Forcing is weak and available moisture is non existent on forecast soundings so I continued with a dry forecast. The heat is expected to return Monday with the upper ridge expanding northward. Southerly flow persists at 10 to 15 mph towards the sfc Monday and Tuesday afternoons. A weak cold front is progged to pass through the area dry Monday evening while weak winds veer back around to the south Tuesday afternoon. The lack of cool air behind the boundary and some compressional warming in the vicinity has raised guidance values to the lower 90s for highs both afternoons. Beginning Wednesday evening, sfc troughing over the western high plains is anticipated ahead of a strong upper low building over the northwest CONUS. Lead upper trough shifts over the central plains Wednesday evening, introducing slight chances for thunderstorms. As the above mentioned upper low approaches the region, occasional storm chances continue before a strong cold front sweeps through the area Friday evening. Throughout the week, highs in the middle 80s and overnight lows in the upper 60s. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 601 PM CDT Sat Sep 17 2016 VFR conditions are expected throughout the period. Fog is possible near dawn tomorrow morning. However, current thinking is cloud cover associated with the thunderstorms across western Kansas shall move over the terminals overnight and hinder fog development. Southerly winds will increase after 15Z to near 10 knots. && .TOP Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...67 LONG TERM...Prieto AVIATION...Baerg