Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/28/17

Area Forecast Discussion
National Weather Service Wilmington OH
1018 PM EDT Sun Aug 27 2017 .SYNOPSIS... A surface trough will rotate northwest into the region tonight. An upper level low and its associated embedded disturbances will bring unsettled weather to the region for Monday and Tuesday. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Upper level low over the upper MS Valley will drop towards the Ohio Valley tonight. A shortwave rotating around the low is forecast to rotate around the base of the low late tonight. Showers are expected to develop ahead of this feature. However the trend of the models is to slow the eastward progression of the pcpn, so delayed the onset of the pcpn by a couple of hours, which keeps the majority of the fa dry tonight. Pooling dewpoints along an inverted trof, well help keep temperatures up. Expect lows tonight in the upper 50s to the lower 60s. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... The embedded s/wv will move northeast across the forecast area Monday morning into Monday mid afternoon. This feature will combine with weak low level forcing from the inverted trof to bring scattered to likely showers. Highest probability for measurable pcpn will be across our northwest zones, with the southeast having the lowest threat. There will be a chance of thunderstorms, mainly during the afternoon, as diurnal instability occurs. Temperatures will reflect where cloud cover is the thickest and rain chances the highest. Highs will range from the mid 70s northwest to the lower 80s south/southeast. For Monday night, the center of the upper level closed low will begin rotating east/southeast toward northeast Illinois/northwest Indiana. We may see a lull in precipitation Monday evening into early Tuesday morning as the first s/wv moves away from our region followed by another embedded s/wv rotating around the base of the upper level low. Have increased PoPs late for the next feature. Instability will wane overnight which should at least diminish the thunderstorm threat. Overnight lows will be pretty uniform in the lower 60s given cloud cover. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Period beings with a closed H5 low centered nr Chicago. The models work this system eastward on Tuesday, while filling it. There should be enough lift to continue with likely PoPs for Tuesday. The atmosphere becomes marginally unstable by late Tuesday morning, so continued with the mention of a chance of thunder. As the low transitions to an open wave Tuesday night, the lift weakens and expect the pcpn to taper off during Tuesday night. Have increased the PoPs on Wednesday however as diurnally driven instability produces some pop up convection. Active pattern continues on Thursday as a cold front drops down through the Great Lakes. The GFS is stronger and quicker with precipitation than the ECMWF. Went with a compromise and kept pops in the low chance category. Models solutions differ from here forward. The GFS has a strong high pressure over the Lakes which provides dry weather for Friday and Saturday. The 00Z ECMWF supported this, but now the 12Z ECMWF is weakening the high and is bringing the remnants of Harvey northward, reaching the fa Friday night. The GEFS and ECMWF means are slower than operation ECMWF, so leaned towards the 12Z GFS/00Z ECMWF solution and waited until Sunday to bring pcpn chances back into the region. Will have to keep an eye on the trends of the models, as this might need to be adjusted. Temperatures will remain slightly below normal through the period. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... A closed H5 low will drop from nrn WI down towards the region tonight. Around the low, a vort max will rotate up the Ohio Valley. In response to the forcing, an area of showers will move from IL to ern IN by 12Z. Previous runs of the RAP and the GFS have been trying to develop some SHRA in the Scioto Valley along an inverted sfc trof between 09-12Z. This seems to be an out lying solution as the latest runs are backing off of this and focusing on the pcpn coming in from IN. The pcpn from the west will push into the tafs after 12Z, with the best coverage around and north of the KDAY area. As the atmosphere warms and becomes unstable, there should be scattered thunderstorms across the region. So started the tafs off with a VCSH at 13-15z, then transitioned VCTS by 15-17Z. Threw in a tempo TS at TDAY from 15-19Z to cover the best chances. The H5 low, will continue to work towards the fa during the day Monday, but it will be filling. This means weakening lift by late afternoon, so transitioned back to VCSH for the end of the taf period. OUTLOOK...Thunderstorms possible Monday night into Tuesday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Hickman NEAR TERM...Sites SHORT TERM...Hickman LONG TERM...Sites AVIATION...Sites
Area Forecast Discussion
National Weather Service Northern Indiana
737 PM EDT Sun Aug 27 2017 .SYNOPSIS... Issued at 338 PM EDT Sun Aug 27 2017 Low pressure is expected to drop slowly southeast from the upper Midwest tonight and Monday, then east across our area Tuesday. This system will bring an increasing chance of showers into the area tonight, with scattered showers and thunderstorms expected Monday and Tuesday. Isolated showers are still possible over eastern portions of the area Wednesday as the low moves away and weakens. A cold front is expected to move across the area Wednesday night and Thursday bringing a low chance of showers, followed by cool and dry conditions Thursday night and Friday as high pressure moves east across the Great Lakes. && .UPDATE... Issued at 720 PM EDT Sun Aug 27 2017 Initial band of showers/isol thunder was attempting to work east to impact NW parts of the forecast area. However, surface observations should little if anything reaching the ground at this point and back edge of radar returns look to be eroding leading to a low confidence forecast into this evening. HRRR attempts to expand coverage and even brings activity well into eastern areas. As a result, will continue to monitor, but make no changes. Equally unsure as to how overnight will unfold with new convection developing from central WI into eastern Iowa. Increase in pops may be needed if this can expand and better organize Otherwise did some minor adjustments to cloud cover. && .SHORT TERM...(This Evening through Monday) Issued at 338 PM EDT Sun Aug 27 2017 Moisture contg to slowly increase across our area from the top down within w-sw flow aloft ahead of upr low dropping slowly sse from ne MN. Shrtwv rotating around the low will move east across IL tonight and then ne across our cwa Monday, likely accompanied by at least sct showers. Fairly steep mid level lapse rates initially tonight could support isolated thunderstorms, but chances still too low to add mention to fcst. Better chc of thunderstorms Monday with diurnal heating allowing for a little more, though still weak airmass destabilization. Cloud cover expected to limit diurnal temp ranges somewhat in this period with lows tonight fcst near 60 and highs Monday in the mid 70s. && .LONG TERM...(Monday Night through Sunday) Issued at 338 PM EDT Sun Aug 27 2017 Sct showers and a few tstms expected to cont Mon night as upr low approaches and continues Tue as low moves slowly east across our area. Wk wind flow beneath the upr low combined with moist airmass and moderate diurnal instability could result in some funnel/landspout activity Tue aftn. Upr low should move east of the area and shear out Tue night, though, wk trailing shrtwv in nw flow behind it could spark a few showers eastern portion of cwa Wed. Tail end of cdfnt associated with stronger shrtwv movg across se Canada/U.S. should move across our cwa Wed ngt/Thu with wk forcing/instability and limited moisture supporting 15-30% chc of showers. Strong sfc high movg across the upr grtlks behind this front should provide mainly clear skies with blo normal temps in our area Thu ngt-Fri. As usual, by days 6-7 medium range model`s solutions diverge significantly with poor run-run continuity yielding considerable uncertainty in the fcst attm. Latest GEM/ECMWF suggest to varying degree that shearing out remnants of T.S. Harvey will lift ne into or through the OH Valley this weekend with associated showers psbly reaching our area. By Sunday-Monday GFS/ECMWF digging nrn stream shrtwv into or toward the upr Grtlks with accompanying cdfnt apchg our area though considerable timing differences, while Canadian lingering Harvey remnants over the OH valley with more subdued nrn stream. Attm, opted for a dry fcst Sat with 20-25% chc of showers by Sunday aftn with temps returning to at or slightly above normal. && .AVIATION...(For the 00Z TAFS through 00Z Monday Evening) Issued at 720 PM EDT Sun Aug 27 2017 Will continue with VFR conditions through the period with some potential for a few showers after 6Z at KSBN and more towards morning at KFWA. Lots of uncertainty as to how precip may unfold with upstream appearance not overly impressive. Better chance for some impacts arrives at KFWA after 18Z Mon. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ UPDATE...Fisher SYNOPSIS...JT SHORT TERM...JT LONG TERM...JT AVIATION...Fisher Visit us at Follow us on Facebook...Twitter...and YouTube at:
Area Forecast Discussion
National Weather Service Lubbock TX
859 PM CDT Sun Aug 27 2017 .UPDATE... Quick update issued to adjust precip chances for tonight. Based on latest guidance handling of MCS up in the Panhandle, rain chances have shifted to the west. Will trim PoPs northeast and extend and increase into chance category across the northwest. && .PREV DISCUSSION... /issued 612 PM CDT Sun Aug 27 2017/ AVIATION... VFR conditions to continue this evening. Models are showing convection in the Panhandle dying out before pushing into the LUB forecast area. Should it hold on, PVW and CDS would be the most likely to be affected but not until around midnight. Confidence in this happening is too low for TAF mention, though. A northerly wind shift will occur after 1 AM, but it will be barely noticeable as winds are expected to remain below 6 KT. PREV DISCUSSION... /issued 300 PM CDT Sun Aug 27 2017/ DISCUSSION... Hi-res models such as the HRRR and Texas Tech WRF show convection pushing into the FA later tonight along an outflow boundary that is currently stalled across northern OK and southwestern KS. Given subsidence aloft and the lack of any discernible weakness in the upper ridge the main forcing mechanism appears to be the boundary itself. Surface moisture continues to remain in place across the region leaving little effort for at least rain showers to develop. A separate front is currently stalled across northern KS behind the outflow boundary and is progged to push into the FA by tomorrow giving one last chance for rain for the coming week. Models are starting to agree with the future progression of the remnants of Harvey by bringing it north to northeastward to the Arklatex region later this week. For the most part this will keep the FA under dry air and subsidence. The GFS keeps the remnants of Harvey far enough westward by the weekend to give the Rolling Plains a chance for rainfall. The ECMWF, however, keeps Harvey further eastward closer to southern AR/northern LA which would keep the Rolling Plains dry. The final path will be determined by how much the Hudson Bay Low amplifies. The ECMWF has a much more pronounced amplification which pulls Harvey northeastward. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 07/74
Area Forecast Discussion
National Weather Service Memphis TN
913 PM CDT Sun Aug 27 2017 .UPDATE... At 9 PM CDT a calm evening is ongoing across the Mid-South. Temperatures are in the low 70s to low 80s, but on track to overnight lows in the upper 60s to lower 70s. Mid to upper level clouds have been present over much of the region this evening, and some shower activity continues over the southern portions of the FA. This activity will likely continue into the night. The forecast is currently on track, and no updates are necessary. ZDM && .PREV DISCUSSION... /issued 254 PM CDT Sun Aug 27 2017/ DISCUSSION...Surface analysis this afternoon places Tropical Storm Harvey near Victoria, Texas while a weak cold front is located over portions of Iowa and Kansas. Some moisture from Harvey has made its way into the Mid-South with regional WSR-88D radars indicating the development of showers and thunderstorms mainly across portions of South/East Arkansas and North Mississippi. As of 2 PM CDT, temperatures across the Mid-South are in the 80s across most locations. Short term models including the HRRR indicate the potential for some isolated to perhaps scattered showers and thunderstorms to continue for the remainder of the afternoon into tonight. Convective coverage is anticipated to increase towards Monday morning as a weak shortwave trough and associated cold front drops into the Lower Mississippi Valley for Monday and Tuesday. Isolated to scattered shower and thunderstorm chances are anticipated to linger across the Mid-South through mid-week as this front weakens further across the region. Latest 12Z long term model trends indicate the future remnants of Tropical Storm Harvey will be located somewhat east of earlier forecasts. Interestingly enough the 12Z ECMWF quickly moves the remnants over the Mid-South by Friday/Saturday and gradually departs towards the end of next weekend. This would suggest a potential for heavy rainfall perhaps late this week into the upcoming weekend if current model trends persist and inclusion into the hazardous weather outlook. CJC && .AVIATION... 00Z TAFs Midlevel VFR ceilings to continue through this evening and overnight. Isolated -SHRA will prevail mainly south and west of MEM. Latest few runs of the HRRR model depict a low level convergence zone from MEM to MKL on Monday, with -SHRA forming as early as 15Z. Some thunder will be possible later in the afternoon, given sufficient surface heating. Otherwise, status quo on Monday, with VFR cigs and light surface winds. PWB && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$
Area Forecast Discussion
National Weather Service Marquette MI
732 PM EDT Sun Aug 27 2017 .SHORT TERM...(This evening through Monday) Issued at 406 PM EDT SUN AUG 27 2017 WV imagery and RAP analysis indicated a mid/upper level low near KDLH, resulting in cyclonic srly flow through the cwa. a shortwave trough near the WI/MI border supported a couple of bands of showers through the cntrl and ern cwa along with a smaller area of tsra lifting into Marquette county where MUCAPE values were in the 500- 800 J/Kg range. Additional weak shrtwvs were located upstream from MN into wrn WI. At the surface, an occluded front extended southward from low pres over the MN arrowhead. Tonight, Models suggest that as the mid level low slowly moves into sw WI the moisture advection and weak to moderate 850-500 qvector conv will diminish with decreasing shra coverage. MUCAPE values should remain high enough this evening to support a few tsra but will drop off overnight with any isold tsra mainly over the far south. Monday, isold/sct shra are expected to linger over cntrl Upper Michigan with an inverted sfc trough extending northward from the low sagging into nrn IL and the possibility of another weak shrtwv rotating into the area. MUCAPE values may also be high enough to near 500 J/Kg again to support some isold tsra by afternoon with pcpn coverage increasing. .LONG TERM...(Monday night through Sunday) Issued at 324 PM EDT SUN AUG 27 2017 Only weather resembling anything significant in the long term is cold/frost potential Wed night and more so Thu night when skies will be clear and winds light. That is the only part of the forecast where grids were changed from the blended initialization, in which a 50/50 blend of BCCONSAll and WPCGuide was loaded for min temps. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 732 PM EDT SUN AUG 27 2017 MVFR conditions will gradually degrade to IFR ceilings and occasionally visibilities tonight as showers dissipate and fog develops overnight. While there will be some improvement Monday morning, VFR conditions will not return until after 18Z at KCMX and KSAW and until late in the forecast at KIWD. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 406 PM EDT SUN AUG 27 2017 Southeast winds to near 30 knots late today will diminish to 15 to 25 knots tonight as low pressure weakens and sags to the south. Winds will then remain below 20 knots through the rest of the forecast period. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Beach Hazards Statement until 8 PM EDT this evening for MIZ014. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...Titus AVIATION...RJT MARINE...JLB
Area Forecast Discussion
National Weather Service Omaha/Valley NE
754 PM CDT Sun Aug 27 2017 .UPDATE... Issued at 752 PM CDT Sun Aug 27 2017 Added a slight chance of showers and rumbles of thunder to western IA through the evening. Couple of showers out there now attached to vort lobe as shown on water vapor imagery, and latest HRRR model continues to move these south through our western IA counties. Isolated thunderstorms in southeast NE have now moved into northeast KS, so that area should remain dry. && .SHORT TERM...(Tonight through Wednesday) Issued at 313 PM CDT Sun Aug 27 2017 Mainly dry and continued cool weather is expected through mid week. Strong vorticity maximum rotating around upper low in northern Minnesota dived through central Nebraska overnight and this morning, triggering a line of wind-producing thunderstorms across central and a small part of eastern Nebraska. System was currently moving off to our southeast, taking precipitation and associated cloud cover with it. Another weak mid level wave rotating through western Iowa this afternoon was helping to steepen lapse rates in that area, leading to some broken cumulus cloud cover. A few showers may result from this instability, but precip and cloud cover should be quick to dissipate with sunset and loss of surface heating. Then surface high pressure is forecast to settle south across the region tonight and linger into Tuesday. Cool and dry north through east low level flow is expected during this time, keeping temperatures on the cooler side of normal under mainly clear skies. By Wednesday, sprawling ridge in the western U.S. will drift a little east, allowing for warmer air to spread through central Nebraska and into western sections of our CWA. Also, lowering surface pressures in the High Plains will promote return flow to parts of eastern Nebraska at that time, but robust moisture return will be held in check as surface high ridges into the Southern Plains and effectively cuts off Gulf moisture. So temperatures will start off in the upper 70s or lower 80s for highs Monday, gaining a category or so each day, putting highs closer to the middle 80s by Wednesday. Most lows should average 55 to 60 each morning. Also of note, with high pressure overhead tonight, diminishing winds and cloud cover will allow temperatures to drop to well below afternoon UPS crossover temperatures, suggesting areas of fog are likely overnight and Monday morning. However drying low levels and some mixing with winds only slowly diminishing may limit reduced visibilities in some areas. Still have enough confidence to mention areas of fog in grids. .LONG TERM...(Wednesday night through Sunday) Issued at 313 PM CDT Sun Aug 27 2017 The mainly dry weather pattern will likely hold through the end of the week and into next weekend. Upper ridging in the West will get suppressed south as longwave trough moves onto the Pacific Northwest coast Wednesday and into the Northern Rockies on Thursday. This wave will dampen as it moves into the Plains, with models suggesting only a minor shortwave tracking across the Dakotas and Nebraska Thursday night and Friday. A weak frontal boundary will follow that wave, settling across Nebraska and Iowa on Sunday. Varying model solutions hint at sporadic chances for showers with shortwave energy Thursday night and Friday, then with frontal system on Sunday. While upper flow pattern is handled similarly between most long range output, little consistency is offered regarding finer details and resulting precipitation. Thus the best course of action at this time is to maintain status quo and not change much from our current forecast of mainly dry and temps in the 60s/80s. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 607 PM CDT Sun Aug 27 2017 There area a couple of showers/thundershowers in the area, but not expected to impact any TAF sites. VFR conditions at both KOMA/KLNK, but some MVFR fog could develop at KOMA 11-13z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ UPDATE...DeWald SHORT TERM...Dergan LONG TERM...Dergan AVIATION...DeWald
Area Forecast Discussion
National Weather Service Phoenix AZ
303 PM MST Sun Aug 27 2017 .SYNOPSIS... Above normal temperatures will continue this week as strong high pressure remains firmly entrenched over the interior West. A modest increase in moisture levels is anticipated today and could result in an uptick in thunderstorm activity this afternoon and evening, mainly east of the Phoenix area. Thunderstorm chances will remain limited across the lower deserts into the middle of this week, with the possibility of cooler temperatures and increasing moisture across the region by next weekend. && .DISCUSSION... Rest of Today and Tonight... Storm activity early this afternoon is indeed looking quite similar to 24 hours ago with a bit more coverage over Yavapai County. HRRR has been pretty consistent in depicting storm activity the rest of the afternoon playing out quite similarly to yesterday with storms forming over moving toward the lower elevations of northeast Maricopa County (metro Phoenix) and Northern Pinal County late this afternoon but struggling to maintain themselves. In the process however, strong winds can be expected. Other CAMs such as NAM Nest and UofA WRF- GFS are not quite as enthusiastic. Of note though, the 18Z NAM Nest has more activity than it`s 12Z run. With the winds will be potential for blowing dust but anticipate the fetch of the winds will not be over prime dust generating areas. Thus expect reduced visibilities will not be like a classic dust storm situation but enough to insert mention of patchy blowing dust for metro Phoenix and northern Pinal County. There is also potential for heavy rain but expect it will be quite isolated and be more likely to occur over/near foothill areas. Otherwise, don`t expect much in the way of precip with this first round of convection. CAMS also depict a follow-on batch of weaker showers moving through south-central Arizona this evening. Some of the solutions show these showers making it west of the Lower Colorado River Valley by 12Z. Overall though, they won`t add up to much. This nocturnal activity appears to be associated with a slow moving short wave depicted by the RAP. Even the GFS indicates some sort of disturbance moving through tonight but it seems to originate with model convection over NE New Mexico. Monday through Wednesday... The high remains centered to our north with an easterly component to the steering flow. However, drier continental air begins moving in and thus, anticipate a bit of a downtrend in convective activity. For a large part of our area (SE AZ and far SE CA), convection related hazards will not be a factor but rather heat is the issue. With no real downtrend in temps expected, extended the Excessive Heat Warning for much of SW AZ and our part of CA through Wednesday. Thursday through Sunday... Things may get a little more interesting into next weekend, as models are fairly consistent showing a tropical system approaching the tip of Baja by Thursday, and slowly moving west/northwestward, potentially spreading a plume of moisture northward into the Southwest. Also of interest, there is the possibility that mid-level moisture associated with the remnants of Harvey could get caught up in easterly flow aloft, and move westward across west Texas and northwest Mexico. While uncertainty surrounding each of these scenarios and the overall large-scale pattern is still high, it still bears worth watching for associated impacts of increased rainfall/thunderstorm potential. && .AVIATION... South-Central Arizona including KPHX, KIWA, and KSDL: Storms currently forming in Gila County are expected to move down near the TAF sites late this afternoon/early evening and dissipate as they do so. Despite weakening storms in the valley, outflow winds will still be a concern favoring the east to north- east direction. Currently have outflow winds in the TAFs but no blowing dust as there is low confidence that will actually happen. Light and isolated showers may linger through late tonight before dissipating. Very similar conditions are expected tomorrow with a chance of afternoon/evening thunderstorms. Southeast California/Southwest Arizona including KIPL and KBLH: No aviation concerns for the next 24 hours as winds generally remain south at KBLH and from the southeast at KIPL. There is a chance winds may switch west to southwest at KIPL late this evening but confidence remains low on that particular solution. Skies will remain mostly clear. Aviation discussion not updated for amended TAFs. && .FIRE WEATHER... Wednesday through Sunday: Storms will generally stay confined to the mountains through our extended period although late afternoon storms in and around Maricopa County, especially those locations near the valley`s edge, is certainly not out of the question. SE California is expected to remain dry. Minimum afternoon humidity will vary between 15-20% for the lower elevations while temperatures will remain above average through at least Thursday. Winds will remain light and typical for this time of year although outflow winds generated from nearby thunderstorms will be gusty and erratic. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Excessive Heat Warning until 8 PM MST Wednesday for AZZ530-532- 533-536. CA...Excessive Heat Warning until 8 PM PDT Wednesday for CAZ561-563- 565>570. && $$ Visit us on Facebook, Twitter, and at DISCUSSION...AJ/Rogers AVIATION...Wilson FIRE WEATHER...Wilson
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Monday) Issued at 242 PM CDT Sun Aug 27 2017 The morning MCS has moved through the area with only a few showers left in east central KS. The synoptic cold front resides somewhere around the I-70 corridor and is forecasted to continue southward through the evening although the convergence appears rather weak. Strong cin has been left in the wake of the MCS, so additional development along the front seems unlikely. A majority of the models keep the area try with only a few solutions showing an isolated shower or storm through early evening. Dry air will slowly filter into the area, so once temperatures cool after sunset fog might be possible especially under clear skies. Overnight the surface ridge stays west and north, so calm winds seem unlikely across eastern KS therefore the boundary layer could stay partially mixed. The RAP soundings show fog developing in the late evening before the advection increases behind the front mainly across east central KS. This is also where a majority of the high res models show the fog potential. Regardless patchy fog may be possible late this evening and overnight. With northerly flow aloft the surface high pressure builds into the forecast area tomorrow with highs approaching lower 80s. .LONG TERM...(Monday night through Sunday) Issued at 242 PM CDT Sun Aug 27 2017 Upper troughing occurs across the Great Lakes while expansive ridge builds over the western CONUS results in northeast Kansas remaining on the dry and mild side. A weak embedded shortwave trough attempts to develop light qpf over the central Plains Wednesday night, however with much of the available moisture focusing with remnants of Hurricane Harvey, kept a dry forecast through the weekend. By Friday night into Saturday, the remnant moisture and convection associated with Hurricane Harvey begins to lift northward. Dependent on the timing of a passing upper trough over the Great Lakes region, a few showers and thunderstorms may impact areas of southeast Kansas and southern Missouri. The GFS is slower with the timing of the upper trough and therefore brings more precipitation into southern Kansas for the weekend. With the high uncertainty, have left a slight chance mention on Friday night, with optimal chances residing in Oklahoma and Missouri. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 622 PM CDT Sun Aug 27 2017 For the 00z TAFs, showers near KMHK will continue to track further south early this evening, with dry conditions expected through the TAF period. The main concern will be for the potential of patchy fog development a few hours before sunrise, as a result of the recent rainfall and the light and variable winds in place. This patchy fog may result in MVFR vis conditions through sunrise, and cannot rule out the possibility of some lower vis conditions near KTOP/KFOE. Once the fog dissipates Monday morning, expect VFR conditions for the remainder of the day. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Sanders LONG TERM...Prieto AVIATION...Hennecke
Area Forecast Discussion
National Weather Service Tucson AZ
903 PM MST Sun Aug 27 2017 .SYNOPSIS...A low grade monsoon pattern will prevail through much of the coming week. Adequate moisture will produce isolated to scattered mainly afternoon and evening thunderstorms, with the greatest coverage east of Tucson and tending to favor mountains. An increase in moisture may bring a corresponding increase in thunderstorms over the weekend or early next week. Daytime temperatures will be above seasonal normals through much of the week. && .DISCUSSION...Another strong and organized outflow from the Mogollon Rim this afternoon. The big difference for most of our area compared to yesterday is a drop off in available moisture. A brisk easterly flow imported precipitable water values below 1 inch from southwest New Mexico into southeast Arizona, with the 00Z KTWC sounding coming in at 0.87 inches. As such, eastern portions of the outflow did little more than generate gusty winds and dust, with most of the benefit from the extra lift felt in areas north and northwest of Tucson. The sun`s down and the outflows are pushing into lower desert locations, so expect a general clearing trend overnight. Please see the previous discussion below for additional details beyond tonight. && .AVIATION...Valid thru 29/06Z. Clearing overnight with Isold -TSRA/-SHRA mainly N-NE of KTUS again after 29/20Z. Otherwise VFR conditions. SFC wind E-SE 5-15 kts with localized gusts to 20 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Easterly winds will prevail across the region thru much of the week. They will be enhanced later tonight into Monday where 20-foot winds speeds will be 12-17 mph with gusts of 15-25 mph. Isolated showers and thunderstorms will be around through Thursday with an uptick in areal coverage possible next weekend or early next week. && .PREV DISCUSSION...A strong ridge north of our area (over the central Great Basin) is dominating our weather. An easterly to northeasterly flow around this feature is bringing in a little bit of drying this afternoon, but all is not lost. The rim is quite active with a more organized outflow than I expected pushing into northern Graham county. Above average height and thickness values from the ridge means above average heat as well. Latest HRRR trends hinting at a few storms around the area this afternoon after all. With troughiness upstream through eastern states, we`ll keep a ridge centered north of our area through most of the coming week. In general that will mean a low grade monsoon forecast, with the exception of one or two afternoons with stronger outflows off the rim providing extra lift (Tuesday?). It`s that time of year though. As we head into September we`ll start staring harder at the tropical Eastern Pacific. NHC has some organization likely just south of Baja in the next several days (probably around mid week). Ensemble means and model consensus showing fairly good agreement (for this far out) in bringing a tropical storm northward over or just west of the southern Baja Peninsula Friday, then near central Baja over the weekend. That would at least help push a deep surge of moisture northward late next weekend or early next week. Something to keep an eye on. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Meyer Visit us on Facebook...Twitter...YouTube...and at