Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/08/20

Area Forecast Discussion
National Weather Service Amarillo TX
633 PM CDT Tue Jul 7 2020 .AVIATION... Generally VFR conditions expected tonight and most of Wednesday, with only a few shots at some storms. This evening, thunderstorms have developed across the northeastern New Mexico plains, with a few of them likely to make it within 10-20 miles of KDHT between 02Z and 04Z. There will be a bit of a wind shift from the storms, but should generally remain VFR with high clouds / ceilings. Storms should continue to diminish overnight, with not much in the way of thunderstorm chances re-appearing in the afternoon or evening hours. Pretty much expect a repeat of today for tomorrow`s forecast, which means scattered storms developing in the far northwest, only to diminish as the storms move south and east. Fox && .PREV DISCUSSION... /Issued 151 PM CDT Tue Jul 7 2020/ SHORT TERM...Today through Tomorrow Night... Current 500mb RAP analysis shows the area of high pressure over the SW CONUS with weak NE flow over the FA. A shortwave disturbance will eject ahead of the main trough pattern that is swinging across the NW CONUS. This shortwave will bring westerlies aloft and be a dynamical forcing for storms off the NM/CO mountains this afternoon into the evening. West northwest flow aloft will continue through tomorrow with another potential shortwave disturbance off the base of trough pattern pivoting with an associated closed low in Canada. An axis of mid-level moisture is present both today in the W FA and tomorrow in the E FA in concordance with thunderstorm chances. Thunderstorm chances have increased today in the W third of the OK/TX Panhandles. Dewpoints are sitting in the upper 50s to lower 60s with an axis of 700mb theta-e setting up along the NM/TX border. MUCAPE values are around 1000-1500 J/kg with 0-6km effective shear around 25 to 30 knots around the time storms enter the FA, which may be the driving factor to help keep storms continuing a bit longer this evening. The storms will enter the northwest portion of the combined Panhandles between 5-7 PM. All the models agree that the storms are likely to create a potentially strong outflow boundary with gusty winds. DCAPE values are around 1500 J/kg, so as storms collapse there is a chance for a severe wind gusts or two to come out of the storms. Storms are expected to quickly diminish to potentially some light showers around 10-11 PM. Tomorrow the chance for storms return in the northeast Panhandles for only a few hours in the evening. Another axis of 700mb theta-e is present along with some surface moisture associated with a potentially weak dryline setup. The NAM3k is the most aggressive with initiating storms in the east, but the NBM also has been trending PoPs higher into the 20s and 30s. The instability exists with MUCAPE values of up to 2000 J/kg and shear of 30 to 40 knots. If the NAM plays out and keeps the better moisture in the eastern Panhandles for storms to initiate, then the main threats will be similar to today with strong gusty winds. Temperatures are continuing the warming trend with highs remaining in the upper 80s to mid 90s today due east southeast winds at the surface. Tomorrow winds will likely be more from the south with highs getting back into the upper 90s to 107 range. However, if winds tomorrow tend to take on a more southeast direction for a majority of the day then that may be what keeps temperatures just a few degrees cooler. Rutt LONG TERM...Thursday through Monday... Upper high over the southern Rockies and southwestern states Thursday of 590 to 593 dam will shifts a little further east Friday and deepen to around 597 to 600 dam Friday. Further intensification of the upper high expected this weekend with 598 to 600 dam before weakening slightly Sunday into early next week around 594 to 598 dam. A cold front should push into the northern Panhandles by Saturday morning and then slowly move southward across the remainder of the forecast area by Saturday night and early Sunday. Max temps only slightly lower Saturday, but will be in the 101 to 110 this weekend into early next week with around 110 to 112 in the Palo Duro Canyon. Max temps Thursday and Friday in the upper 90s and around 100 to around 110 to 111 in Palo Duro Canyon. Will likely be needing a Heat Advisory or Excessive Heat Warning between Thursday and Monday. Schneider FIRE WEATHER...Saturday through Monday... Due to the hot temperatures and minimum afternoon relative humidity values of around 10 to 15 percent, RFTIs of around 1 to 2 will be possible. Could possibly have some elevated fire weather concerns this weekend into early next week, however 20 foot south and southwesterly winds of 10 to 15 mph will mitigate the threat and will be mainly relative humidity-driven elevated fire weather. Schneider && .AMA Watches/Warnings/Advisories... TX...None. OK...None. && $$ 14/77
Area Forecast Discussion
National Weather Service Bismarck ND
1012 PM CDT Tue Jul 7 2020 .UPDATE... Issued at 1010 PM CDT Tue Jul 7 2020 Severe threat continues over the area as strong thunderstorm wind reports continue to pour in over western North Dakota. Expect this to continue to push to the east. UPDATE Issued at 800 PM CDT Tue Jul 7 2020 Severe Thunderstorm Watch number 340 has been issued for all of western and much of central North Dakota until 200 AM CDT/100 AM MDT. Multiple severe wind reports continue to come in over eastern Montana as the line continues its approach. UPDATE Issued at 647 PM CDT Tue Jul 7 2020 What was stated in the previous discussion continues to hold true with the expected severe weather event tonight. Severe storms continue to quickly race through eastern Montana, with the main line producing 80+ mph wind gusts reports west and southwest of Glasgow. The whole line continues to push east at around 50 to 60 mph and is currently pushing through Glasgow. A secondary area to the south developed off the northern Bighorns, and also continues to push towards the area. Models continue to have the low level jet strengthening tonight ahead of system, sustaining the severe convection. && .SHORT TERM...(This evening through Wednesday) Issued at 254 PM CDT Tue Jul 7 2020 Severe thunderstorms are likely tonight, with the possibility of a significant, high-end damaging wind event, but with uncertainty in the event`s overall magnitude due to midlevel capping. At mid afternoon, mass-field responses are underway in response to the strong middle- and upper-level shortwave trough approaching central MT, with ~4 mb/3 hour surface pressure falls centered over eastern MT and western ND. Resultant low-level southeast flow has allowed surface dewpoints to rise into the lower and middle 60s F, with additional moisture advection expected to yield MUCAPE on the order of 2500-4000 J/kg from this evening into tonight in western and central ND. The greatest bouyancy will be in southwestern and south central ND, near a low- and midlevel warm frontal zone, with relatively-richer moisture. Forecast soundings from several model cores strongly suggest midlevel capping could be an issue tonight, despite falling heights and DCVA aloft and its related cooling, with CIN for both elevated and boundary-layer-based parcels of -50 to -150 J/kg possible, especially in the area of greatest CAPE. However, even small boosts in boundary layer moisture -- perhaps not much greater than that which is already ongoing based on observed afternoon dewpoint trends -- may yield sufficiently-low CIN for maintenance of organized convection moving into the state from MT. Moreover, if sufficient clustering and upscale growth of the MT convection occurs before it arrives, then well-established cold pools may be sufficient for slab-type ascent through a deep enough altitude to maintain organized MCS structures into central ND, where capping could be strongest. Thus, the magnitude of low-level moisture advection into southwest and south central ND by early evening, and the degree of upscale growth and strength of cold-pool-related ascent upstream by then, will be key mesoscale components in determining the magnitude of tonight`s event. Capping concerns aside, the parameter space will be characterized by both large CAPE and strong wind fields with deep-layer shear magnitudes of 50-60 kt, 0-3-km bulk shear on the order of 30 kt, and low-level, 0-1-km SRH on the order of 200-400 m2/s2, all supportive of both organized bowing structures as well as embedded yet persistent mesocyclones which could yield both an enhanced risk of damaging winds of 80+ mph and tornadoes. Passage of the strong shortwave trough is also indicative of a possible higher-order, organized damaging wind risk. GOES-East satellite imagery through 1945 UTC shows both increasing convection near the cold frontal zone in central MT, and attempts at convective initiation in the higher terrain of south central MT and north central WY. This is in line with the well-clustered CAMs including the 12 UTC HREF members and HRRR cycles through its 18 UTC iteration, which strongly support one or more storm complexes reaching western ND in the 00-03 UTC time frame and central ND in the 04-06 UTC time frame. Given the aforementioned parameter space and balancing uncertainty of midlevel cap strength which itself is apt to be regulated by low-level moisture advection, we believe two primary outcomes could occur tonight: 1) Semi-organized complexes of storms with some embedded bowing segments cross the area with occasional damaging winds and hail risk, but with potential weakening with east and southeastward extent due to midlevel capping, or 2) A well-organized, upscale-growing bowing MCS develops across southwest ND and races northeast, with potential for a high-end damaging wind event that could approach derecho scales within at least a narrow corridor where the intense convection intercepts rich low-level moisture with local weaknesses in capping near the warm frontal zone, amid very strong low- and deep-layer shear. In this scenario, QLCS spin-up tornadoes are also very possible, in addition to larger-scale embedded-mesocyclone tornado risks. Note that this scenario is highly conditional and uncertain due to the potential for capping. It is not yet clear which of the two scenarios will occur, with some latitude for a scenario in between, with much dependent on mesoscale details through early evening. Recent trends in CAMs suggest the highest potential for outcome number two could be along an axis from Bowman and Dickinson toward Center and Washburn, where the 12 UTC HREF probability of UH >150 m2/s2 exceeds 50 percent. Again though, we need to message the risk while bearing in mind capping could play a role in this event moreso than perhaps earlier thought. Regardless, storms are expected to quickly clear the area by about 09 UTC, with a drier, post-frontal westerly flow on Wednesday. .LONG TERM...(Wednesday night through Tuesday) Issued at 254 PM CDT Tue Jul 7 2020 A drier period is on track Wednesday and Thursday with slightly cooler temperatures as the region finds itself on the southern flank of an upper-level low in southern Canada. Thereafter, the subtropical ridge is forecast to strengthen south of the local area, with increasing mean westerly flow to its north. The 12 UTC global model suite suggests a shortwave passage centered on Friday afternoon and Friday night will deliver the next round of possible strong to severe storms, as supported by the CIPS Analog Severe probabilities. Thereafter, NBM-based PoPs support a drier period over the weekend, with some uptick in convective potential again next week as the flow aloft may return to a southwest direction. Highs Friday into next week are mainly forecast to be 85 to 95 F. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 647 PM CDT Tue Jul 7 2020 Strong to severe thunderstorms are likely beginning in western ND around 01 UTC, and quickly moving into central ND by about 04 UTC. The storms could be severe with enhanced potential for damaging surface winds of 50 kt or higher, along with local IFR or LIFR conditions. The storms will move out of the area by 12 UTC as a cold frontal passage occurs. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JJS SHORT TERM...CJS LONG TERM...CJS AVIATION...JJS
Area Forecast Discussion
National Weather Service Dodge City KS
500 PM CDT Tue Jul 7 2020 ...Updated Aviation... .SHORT TERM...(This evening through Wednesday) Issued at 333 PM CDT Tue Jul 7 2020 GOES 16 sat and mesonet data showing few to scattered cu field around 6kt ft across southwest Kansas. Highs ought to top out in the low to mid 90s this afternoon , with warmest temps in the 95-98 F range over the western counties. The CAMs all generate clusters of convection across eastern Colorado late this afternoon, and stall out/decay the convection presumably from the very weak upper flow aloft from the mid level ridge axis, before any storms are able to enter western Kansas this evening. There could be a gust front coming in from the west as well over the westernmost counties depending on where the storm clusters dissipate, but threat from thunderstorm wind gusts is extremely low. Beyond the evening, mild overnight temperatures are expected area wide overnight, with upper 60s near the Colorado/Kansas line but around 70 degrees elsewhere. .LONG TERM...(Wednesday night through Tuesday) Issued at 333 PM CDT Tue Jul 7 2020 For Wednesday, a dryline will move a little farther east, allowing hotter temperatures, along with slightly decreased heat indices west of the highway 23 corridor, while temperatures across the central Kansas counties will be likely relegated to the upper 90s but very humid as dew points remain in the mid to upper 60s from Wakeeney to Dodge City and Meade and points eastward. The NMM right now is the only model that allows convection along the dryline starting around 21 UTC (4 pm) west of Liberal and expanding north along the feature through Garden City to near Scott City. None of the other CAM models are allowing convection to develop at this point, but do all agree on a large mcs developing over central Nebraska around the same time. Therefore small chc pops are found across our northeast counties Wednesday night. By Thursday evening the model signals are a little more favorable for convection more directly impacting the forecast area, as a weak nw flow shortwave is noted in the GFS/EC. Convection could initiate in a couple of areas along a farther east dryline, impacting the southeast counties as well as moving in from northwest Kansas in the evening. Thunderstorms, whether severe or not are not favorable in the far sw kansas counties Thursday evening. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 500 PM CDT Tue Jul 7 2020 VFR/SKC will continue through this TAF cycle. Only expecting some scattered cumulus in the afternoon, and cirrus anvil debris from Colorado convection overnight. Convection ongoing in SE Colorado as of 22z is forecast by HRRR to dissipate near EHA around 02z Wed. Kept all TAFs dry with no mention of thunder. SE winds of 8-12 kts will prevail through sunrise Wednesday. After 15z Wed, expect strong south winds at DDC/GCK/LBL, sustained near 20 kts with gusts near 30 kts. South winds will be about 5 kts weaker at HYS. && .PRELIMINARY POINT TEMPS/POPS... DDC 70 99 72 100 / 0 0 10 10 GCK 69 102 68 99 / 0 0 10 10 EHA 68 103 67 101 / 10 0 0 0 LBL 69 105 69 103 / 0 0 0 0 HYS 71 95 69 95 / 0 10 20 20 P28 70 99 74 104 / 0 0 0 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Russell LONG TERM...Russell AVIATION...Turner
Area Forecast Discussion
National Weather Service Des Moines IA
647 PM CDT Tue Jul 7 2020 .DISCUSSION.../Tonight through Tuesday/ Issued at 339 PM CDT Tue Jul 7 2020 Weak MCV moving across northeast Iowa with convection firing to the east/northeast of the system. No thunderstorm development over the southeast yet despite good instability and little convective inhibition. The HRRR remains over zealous in that area as well suggestion scattered thunderstorm development in that area already by 19-20z. Still possible for a few storms over the next few hours and given the lack of shear and DCAPE values over 1000 J/kg, stronger updrafts could produce higher wind gusts and possibly isolated hail. Generally quite weather overnight with no precipitation with lows in the lower 70s. Warmer air moves over Iowa on Wednesday as the thermal ridge moves further east though the much warmer air will remain south and west of the state into Nebraska and Kansas. The pressure gradient will be increase over the past few days and will allow for breezier conditions. Also, this should allow dew points to mix to a degree and keep readings in the 70 degree range. Overall, temperatures should be a few degrees warmer than today with dew points near to slightly lower. Heat index values will be near 100 in places during the afternoon. Several of the CAMS are suggesting a few thunderstorms over southeast Iowa and while the area will be highly unstable, the lack of a forcing mechanism should limit any thunderstorm potential. Thunderstorms are expected to develop along a frontal boundary over South Dakota and Nebraska then evolve into an MCS as the low level jet increases in the evening. The most likely scenario would have an MCS roll down the stronger instability gradient near or just west of the Missouri River Valley and this leaves a fair amount of uncertainty regarding precipitation chances into central Iowa later Wednesday night into Thursday. Have lowered pops some during this timeframe due to chances of being split, however, precipitation chances are likely still too high. A shift to northwest flow will occur following the early Thursday system with large high developing across the southwest CONUS and a long wave trough to the east. This will lead to slightly cooler conditions Thursday and Friday. A system dropping through the northwest flow will bring a chance for thunderstorms Friday night into Saturday morning. Again, the confidence over placement remains lower than average as the MCS could drive further to the west. Otherwise, typical mid July weather this weekend and into next week. && .AVIATION.../For the 00Z TAFS through 00Z Wednesday evening/ Issued at 646 PM CDT Tue Jul 7 2020 Confidence is fairly high in VFR conditions through the period, with mainly a diurnal cumulus cycle. No precipitation is anticipated with mainly southerly winds at non-impactful speeds. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ Small DISCUSSION...Donavon AVIATION...Small
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1155 PM EDT Tue Jul 7 2020 .AVIATION... Nocturnal stability in control through the overnight period, yielding simply some lingering pockets of higher based cloud cover. Some potential for shallow MVFR level fog formation at one or terminals during the pre-dawn hours, potential too limited to highlight attm. Standard high based diurnal cu field emerges Wednesday within existing hot/humid environment. This environment will offer at least an isolated potential for late day showers and thunderstorms, perhaps focused in the vicinity of the Detroit corridor along advancing lake breeze activity. DTW THRESHOLD PROBABILITIES... * Low for thunderstorms Wednesday mid afternoon into the evening. && .PREV DISCUSSION... Issued at 337 PM EDT Tue Jul 7 2020 DISCUSSION... Satellite this afternoon is showing a surface convergence zone along Lake St Clair due to the lake breeze helping to initiate an occasional isolated shower. The Saginaw valley has been the focal point for numerous showers and thunderstorms thanks to the trailing edge of the pre-frontal trough that crossed northern MI late this morning. Gusty winds will be possible with these storms due to steep low level lapse rates (around 9 C/km with the latest RAP analysis). Updraft strength in the strongest cells have been sufficient for the production of pea-sized hail as well. The Tri-Cities area and Thumb will continue to see the bulk of convection this afternoon/evening being closer to the main forcing out ahead of the cold front. Scattered development across the rest of lower MI will continue through the evening resulting mainly from daytime heating with chances rapidly decreasing after sunset. Upper level wave quickly transitions east into Quebec tonight into early Wednesday morning pulling the weak cold front back north away from the CWA. Upper level ridge immediately follows maintaining the heat over SE MI for Wednesday. Airmass under this ridge is the same that the region has experienced the past several days so expecting more of the same. 850mb temps remain around 18C leading to another day of mid-90`s and dewpoints in the mid-60`s. A few isolated showers and storms are possible Wednesday afternoon bubbling up in this hot, humid airmass but subsidence under the ridge in the mid- levels will help to limit convective potential. Thursday the ridge axis moves east of lower MI allowing for increased southerly flow in the low- and mid-levels. This will further solidify heat and humidity likely making Thursday the hottest day of this week. Apparent temps will reach into the upper 90`s by Thursday afternoon. Friday brings the best chance for widespread rain. Low pressure moving across the central Plains into the northern Great Lakes will drag a cold front across lower MI late in the day Friday. Still a ways out but currently there looks to be the potential for moderate instability with the latest model suite indicating MUCAPE around 1000J/kg, however, shear isn`t looking impressive yet for good storm organization. Some uncertainties remain with timing as the GFS continues to be quicker bringing the shortwave into the region by Thursday whereas the Euro has been slower with the bulk of the rain late Friday afternoon through the first half of Saturday. Post fropa highs this weekend will only be in the mid to upper 80`s with a slight reduction in dewpoints into the lower 60`s. MARINE... A weak cold front over southern Lake Huron will continue dropping southward through this evening resulting in scattered thunderstorms and brief wind gusts to around 35 knots. Winds will flip around to the northwest behind the front this evening and will linger from the north through the overnight while remaining fairly light. High pressure will build back over the region Wednesday and will hold through Thursday while drifting slowly east. This will bring about the return of southwesterly flow. The area should stay dry after this evening convection ends with the next chance of storms holding off til Friday. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...Heat Advisory until 8 AM EDT Wednesday for MIZ061-062-068>070-075- 076-083. Excessive Heat Watch from 8 AM EDT Wednesday through Thursday evening for MIZ061-062-068>070-075-076-083. Lake Huron...NONE. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ AVIATION.....MR DISCUSSION...KDK MARINE.......DRK You can obtain your latest National Weather Service forecasts online at
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1002 PM EDT Tue Jul 7 2020 .SYNOPSIS... A low pressure system will slowly drift east across Georgia and South Carolina today, then continue a slow track up along the East Coast through the rest of the week. Rain chances will be in store every day of the forecast period with drier air trying to work into the area by Sunday. Better chances for rain will be in store for the early part of next week. && .NEAR TERM /THROUGH WEDNESDAY/... Evening Update...Lowered PoPs across many areas as banding -shra has dissipated or weakened sigfnt/ly across the FA. Will cancel FF.A with this update as no flooding is occurring and no new hydro issues are expected through the evening and overnight. 730 PM Update...No sigfnt changes made to the going fcst outside of tweaking PoPs down based on ongoing metwatch. May drop FF.A before expiration time as precip has not accumulated over the watch area, nor are prolonged high rates or training cells anticipated thru the evening. 500 PM Update...Rounds of showers and a few thunderstorms continue to swing across the area this evening. Expect quickly reduced vsbys to arnd a mile or less in the heavier showers as the column remains quite moist with PWATs arnd 2 inches. Continuing to monitor the srn Upstate and NE GA for possible flooding as antecedent conds remain high, esp across Elbert Co. As of 230 pm EDT: Banding and rates have generally been quite weak within the remaining Flash Flood Watch area, with mainly light precipitation over the past few hours. Nevertheless, the latest RAP run and a few of the mesoscale models depict newly developed bands trying to wrap west across the lower Piedmont, especially from Greenwood to Abbeville, through the evening hours. Thus, will keep the watch going from Elbert to Laurens, for at least a few more hours, given that some localized 1 to 2 inch rain totals have already occurred in this tier, and any new bands will be efficient rain producers. Otherwise, a leading wave of 500 mb vorticity will likely lift northeast of the area through the early evening hours, while a trailing vort lobe provides forcing through at least the late evening hours, and possibly into the overnight. The main 850 mb circulation center poised to cross the central Savannah River this afternoon should reach northeast SC by daybreak Wednesday. This will lead to a steady dropoff in overnight PoPs, with the best lingering chances across the eastern half of the forecast area. As the circulation moves to eastern NC through the day on Wednesday, low-level flow will become more northerly. Even though profiles remain moist, this should cut down on upslope flow and associated PoPs. There could well be better instability with slightly warmer temps, and low-level convergence and ridgetop triggering may lead to more afternoon thunderstorms - which would be the primary producer of any additional heavy rain/flooding threat. Temperatures will run at least 5 degrees below climo for maxes on Wed. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... As of 215 PM EDT Tuesday: The weak, broad area of low pressure will remain over the general area as we move into the short term, slowly pushing east through the period. Best moisture will remain along the coast with the associated surface low, but with the upper weakness and another approaching shortwave, still should see a diurnal trend with pops through the period remaining generally above-climo. There may be some concern with locally heavy rainfall in the mountains and of course cannot rule out an isolated pulse severe seems slightly better for this on Friday with the approach of the secondary upper trough. Temps will remain fairly close to seasonal normals, though slightly warmer on Friday than Thursday. However, with the plentiful low-level moisture around, could start seeing some heat index issues Friday, as current forecast is starting to bring some >100 degree HIs into the Upstate Friday afternoon. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... As of 200 PM EDT Tuesday: The overall pattern in the extended forecast is very well agreed upon between the global models. An upper trough is expected to impact the area during the forecast period. This should keep the tropical low on a northeasterly track as it should be well off the Carolina coastline by the extended forecast period. The upper trough will dig in from the Midwest and eventually the Ohio River Valley Friday night into Saturday. An attached frontal boundary will allow for scattered activity to persist ahead of the boundary with any tropical moisture that`s still hanging around in the area until the frontal passage takes place between 18Z Saturday and 00Z Sunday. Drier air should filter in during the second half of the weekend with temperatures expected to be slightly above climo. As we move into Sunday and the early part of the new work week, the upper trough will take its time to pull out of the region and help increase PoPs, especially Monday into Tuesday as diurnal activity will get a boost from the upper level lifting and destabilization from surface heating. Temperatures will remain at or slightly above climo through the rest of the forecast period. Southwesterly flow and a low-level moisture flux allows for higher PWAT values to return as most of the cwa will be >1.50" during that time frame. An active pattern may be in store for the region during the first half of next week. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... At KCLT and elsewhere: Tricky TAF set with lingering bands of precip sweeping across the region. These shower bands have lowered VSBY to IFR or lower at times and have been hard to fcst or time into a specific location. Anyway...have generally lowering precip chances overnight due to loss of heating and lowering CIGs to MVFR most locales except IFR CIGS at KAVL, KCLT and KHKY before daybreak. Slowly improving flight conds in the morning to MVFR/VFR arnd mid day. Have included a PROB30 TSRA Wed afternoon all locales as better insol will make for higher instability than has been the case recently. Winds will remain e/ly to ne/ly outside the mtns and nw/ly at KAVL during the afternoon. Low end gusts are possible as well. Outlook: A return to more diurnal afternoon and evening showers and thunderstorms is expected late this week through the weekend. This will mean mainly MVFR restrictions under any showers and storms, and then morning IFR to MVFR cigs/visibility possible around daybreak each day, especially in the river valleys. Confidence Table... 02-08Z 08-14Z 14-20Z 20-00Z KCLT High 90% High 95% High 82% High 100% KGSP Med 67% High 93% High 86% High 100% KAVL Med 78% Low 57% Med 79% High 100% KHKY High 84% High 85% Med 65% High 100% KGMU Med 77% High 87% High 97% High 100% KAND Med 67% Med 78% High 86% 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 are available at the following link: && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...CAC NEAR TERM...HG/SBK SHORT TERM...TDP LONG TERM...TDP AVIATION...SBK
Area Forecast Discussion
National Weather Service Marquette MI
732 PM EDT Tue Jul 7 2020 .SHORT TERM...(This evening through Wednesday) Issued at 303 PM EDT TUE JUL 7 2020 Uffda, more warm weather across Upper Michigan today and another hot one expected tomorrow for most of the UP. As of 18Z, GOES imagery depicts generally sunny skies with some diurnal cu developing around 4kft. Can see the developing lake breezes clearly in the cu field movement, as Lake Superior`s is winning the race, but Lake Michigan`s is starting to push inland now. These lake breezes will be the focus for any potential thunderstorm development this afternoon into this evening. CAMs still are showing a few isolated thunderstorms to develop across central UP as the two lake breezes enhance convergence. This added convergence will be needed for any thunderstorms to develop as model soundings have been consistently showing a slight capping inversion with latest RAP showing 500 to 800 J/kg and 35 kts bulk shear. With that, no widespread svr storms expected, but as with any lake breeze thunderstorm there is a chance for some smaller hail and gusty winds if any cell can ride along the lake breeze long enough to develop before the core falls back down. Tonight, lows were a little tricky as a weak ridge of sfc high pressure did bring in some drier air across the west half of the UP today, lowering PWATs; however, as an increase in SW winds begins across the west tonight, PWATs and WAA increase. Ultimately brought lows up a degree or two, but still expecting interior west to fall into the mid to upper 50s, near 60 across the east, and low 60s along Lake Superior. Tomorrow, mid-level ridging increases as SW flow continues to bring an increase in WAA and moisture across the UP. To the west across Saskatchewan, a closed mid-level low will remain nearly stationary, slowly shifting east through the rest of the week as a shrtwv and sfc trough extends to the south through the Dakotas. With the trough remaining off to the west tomorrow, increased flow PVA and WAA will bring a chance of showers and thunderstorms across western Lake Superior, but have generally left any PoPs out of the forecast over the land for now per 12Z CAMs. There may be a shower or two that squeaks in across the west in the morning as a nocturnal complex dies out moving through Duluth, and then again in the evening as a complex of thunderstorms develops across MN and travels over Lake Superior into Upper Michigan. Regardless, its going to be HOT tomorrow with heat indices pushing into the mid 90s. .LONG TERM...(Wednesday night through Tuesday) Issued at 302 PM EDT TUE JUL 7 2020 Upper air pattern consists of a 500 mb ridge across the upper Great Lakes with a shortwave over the northern plains 00z Thu. This shortwave moves into the upper Great Lakes Wed night into Thu. This shortwave moves into the lower Great Lakes on Fri. Deeper moisture and 850-500 mb q-vector convergence moves in for Wed night through Thu before moving out on Fri across the west, but lingering across the east half of the cwa. Overall, did not make too many changes to the going forecast. In the extended, the GFS and ECMWF show a 500 mb trough across the ern U.S. and a ridge across the Rockies 12z Sat. The ridge moves to the east into the northern plains 12z Sun and into the upper Great Lakes 12z Mon. A shortwave moves into the northern Rockies 12z Tue and into the northern plains late on Tue. Temperatures will stay above normal for this forecast period. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 731 PM EDT TUE JUL 7 2020 VFR conditions will continue through most of the forecast. Dewpoints have recovered a bit at KSAW and are approaching the mid 60s this evening, which is close to where the were this AM when fog developed there. KCMX is also in a similar situation with dewpoints in the lower 60s. Main difference is that neither site is expected to receive any precipitation overnight. While there is less confidence in fog development at those sites tonight despite the mostly clear skies, light winds and abundant low-level moisture, it remains a possibility, so have included a brief period of fog late tonight. A bit more confident at KIWD with fog development there, thanks to local influences and have brought in lower ceilings and visibilities at that site for a time late tonight. Once we get into the daylight hours VFR conditions return. The next challenge is the timing of convection at the western TAF sites...and at this time only expect a very slight chance of convection at KIWD by late in the forecast. Have left mention of showers and thunderstorms out for now, but this will be included in the latter part of the forecast for the 06Z package. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 303 PM EDT TUE JUL 7 2020 Under a continued warm and moist airmass, Lake Superior will continue to see patchy fog, locally dense at times, throughout the forecast period. These chances will increase if any precipitation moves over the lake. There will be some thunderstorms moving over western Lake Superior early on Wednesday and then again on Wednesday night. There may be a few gusts up to 20 knots or so tomorrow from the ESE, otherwise winds are expected to remain blo 20 knots through the fcst period. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JAW LONG TERM...07 AVIATION...RJT MARINE...JAW
National Weather Service Raleigh NC
945 PM EDT Tue Jul 7 2020 .SYNOPSIS... Low pressure will slowly drift east toward the Georgia-South Carolina coast tonight along a stationary front that extends east through Alabama, Georgia and central South Carolina. The area of low pressure will slowly drift northeast across the eastern Carolinas on Wednesday and Thursday. A trailing cold front will linger across the Carolinas into the weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 945 PM Tuesday... 01Z surface analysis shows the surface low WNW of Savannah, tracking E before it turns up the Carolina coast tomorrow. Earlier showers and isolated storms really diminished after 21Z, with only a couple areas of light showers near Winston-Salem and Fayetteville, with more but still scattered radar returns over NE SC. Even as the low begins to track a little more north, the low-level ENE flow is rather light, so there shouldn`t be much shower coverage overnight outside of the southern coastal plain and perhaps in the western Piedmont where isentropic/terrain upglide is a little better. Low clouds should expand across the area after midnight, and pockets of fog can`t ruled out (noted by HRRR in the Piedmont). Lows in the lower 70s. && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... As of 245 PM Tuesday... The surface low will be near the coast of SC by Wednesday morning, with the boundary extending northeast along the NC coast and west through GA. The low is expected to sit over the SC coast through Wednesday night, possibly drifting slowly east-northeast to just offshore by Thursday morning. The axis of highest rainfall chances and amounts will be along the NC coast, with northerly flow on the back side of the low resulting in a bit drier weather over much of the Piedmont. The question will be how far west the boundary migrates during the day, with some models suggesting it could nose into the Triangle area. Best instability will generally be along and east of I-95 Wednesday afternoon but shear will be limited. The SPC has central NC in just general thunder. Showers and isolated thunderstorms will likely develop during the aft and die off again after sunset. Highs will again be below normal, generally in the low to mid 80s with lows around 70 degrees, give or take a few degrees. && .LONG TERM /THURSDAY THROUGH TUESDAY/... As of 157 PM Tuesday... The weak upper low will slide offshore on Thursday, although an elongated trailing trough will remain in place across central NC Thursday into Friday. Despite anomalously high PW values above 2 inches area-wide, mid level moisture transport is largely unimpressive over land Thursday and Friday with the highest values displaced well offshore. While there will be a continued chance of mainly diurnal precip to close out the week, the heaviest showers should remain east of the forecast area. As soon as the aforementioned low moves offshore, another longwave trough and associated surface cold front will move through the Appalachians Saturday into Sunday. What happens to the southern end of this longwave trough has been the source of struggle among the deterministic models the past few days, and today`s model runs still depict varying solutions. The EC cuts off a weak low overhead Monday and Tuesday whereas the GFS advertises a somewhat drier solution but with a stalled front nearby. Probabilistic guidance and NBM suggest at least a mention of precip early next week and this seems reasonable at this lead time. Depending on how things evolve synoptically, modest mid level flow in the vicinity of a stalled upper low could result in a convectively favorable (potentially severe) environment early next week but it`s still too early to have much confidence in this time period. As for temps, look for below normal highs Thursday, recovering Friday and Saturday, followed by a slight post-frontal retreat Sunday into next week due to elevated precip chances and post- frontal airmass. Overnight lows will remain near normal throughout in the lower 70s. && .AVIATION /00Z TUESDAY THROUGH SUNDAY/... As of 745 PM Tuesday... 24 hour TAF period: Somewhat of a persistence forecast as a surface low migrates across central SC to the NC/SC coastal border area tonight and moist ESE flow continues across central NC. Earlier showers and very isolated storms have diminished. and most sites will be dry overnight, with ceilings falling to MVFR (perhaps IFR at FAY) after 06Z. A few showers may move inland toward FAY after 08Z as the low tracks toward MYR. Expect showers to again increase across central NC by midday Wednesday as the low moves slowly up the NC coast, with mostly VFR conditions, briefly dropping to MVFR is heavier showers. Looking ahead: Periods of showers and sub-VFR will continue into Thursday as the surface low tracks slowly up the NC coast. Improving conditions are expected Friday into the weekend. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...KC/Blaes NEAR TERM...bls SHORT TERM...KC LONG TERM...Leins AVIATION..bls
Area Forecast Discussion
National Weather Service Reno NV
228 PM PDT Tue Jul 7 2020 .SYNOPSIS... A dry weather pattern will continue this week with daily zephyr breezes and seasonably warm temperatures. Smoke impacts can be expected near the Numbers Fire. A slight increase in wind early next week could lead to critical fire weather conditions. Thunderstorms are possible over the mountains this weekend into next week, however coverage appears spotty. && .DISCUSSION... * Gradual warming the next few days as a series of troughs coming out of the Pac NW counteract the Four Corners heat ridge attempting to establish itself. Peak temperatures appear to be Friday through Monday, per NBM guidance, however only about 3-6 degrees above normal. Not too bad considering we`re in the climatological peak of impactful heatwaves. * With these passing troughs there is potential for stronger zephyr winds at times but simulations continue to be somewhat scattered on which days could bring more fire/transport/recreation impacts. Right now Saturday-Monday has the best chance. In any event it would be merely a "zephyr+" type situation, but with super dry airmass and vegetation that would be enough for another round of critical fire weather conditions one or more of those days. * Dry airmass will keep t-storms at bay through this week. Starting this weekend some of the probabilistic guidance suggests chances for mountain t-storms but odds are pretty skimpy. Mainly Mono- Mineral Counties and east of Lassen Peak - the typical hot spots. It`s not really until next week that precipitable water values rise enough for meaningful t-storm chances. -Chris && .AVIATION... * Pretty quiet on the aviation weather front much of this week. Zonal flow aloft leading to typical afternoon and early evening westerly breezes. Gusts generally at or below 25 kts. * One exception is smoke and haze from the Numbers Fire SE of MEV. Assuming continued fire activity, which seems like a safe bet looking out the window, HRRR smoke model shows good potential for MVFR conditions at MEV and possibly HTH tonight into Wednesday morning. Smoke will transport east/southeast from the fire in the afternoon and evening, and then settle in to the valleys late at night. Radar showing plume lofting to about 20,000 feet before spreading out to the east. -Chris && .FIRE WEATHER... ...Dry and Breezy Conditions Through This Week... Very dry airmass remains in place through the week with humidity in the teens and single digits. Poor overnight recovery is expected each night as well, especially in the thermal belts. Typical afternoon and evening zephyr breezes will occur each day this week and into the weekend, with gusts up to 20-30 mph. For the ongoing Numbers Fire near Gardnerville, these dry and breezy conditions will continue through this evening, then diminish overnight with heavy smoke draining into the Carson Valley and Mason Valley. Dry conditions will be present overnight for the Numbers Fire, as the Pine Nut Mountains are a known thermal belt in our region. Also, as the fire continues to move into the higher elevations of the Pine Nuts, winds will remain breezy until around midnight. Instability is good today, although a capping inversion around 15k ft will keep the plume from reaching great heights. As the sun sets this evening, we will see the atmosphere become more stable overnight. There is a bit more instability Wednesday as a weak shortwave trough passes through Northern California, bringing steeper lapse rates aloft and increase our Haines Index to 5. This could lead to larger plume development if the fire continues to align with fuels and topography. We should remain in dry southwest flow through the weekend. Chances for thunderstorms are looking less likely for early next week, although there is a possibility that we could see a stronger shortwave and increasing gusty winds around Monday. -Hoon && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$ For more information from the National Weather Service visit...
Area Forecast Discussion
National Weather Service Springfield MO
603 PM CDT Tue Jul 7 2020 ...Updated 00Z Aviation Discussion... .SHORT TERM...(This evening through Wednesday) Issued at 211 PM CDT Tue Jul 7 2020 A nice cumulus field has developed across the area this afternoon, with updrafts achieving both better height and coverage than previous days. At 500 mb, a broad ridge has helped dampen thunderstorm activity. Still, the convective environment is favorable enough to support scattered showers and thunderstorms through late afternoon. This environment has been characterized by little CIN, adequate instability (1000-2000 J/kg MLCAPE), and just enough mid- and upper-level moisture for updrafts to punch through the LFC. While we are not anticipating any severe storms, the RAP is suggesting Theta-e differentials between 20-25 K. This may result in a few stronger updrafts with 40-50 MPH downburst winds and penny- sized hail. Otherwise, the primary hazards with this activity will be occasional cloud-to-ground lightning and heavy downpours that will result in poor visibility. Any showers and storms that develop this afternoon will quickly dissipate near sunset. Temperatures tonight will cool to 70 degrees. For Wednesday, the afternoon convective environment will be less favorable, and coverage will be more isolated. This will be due to dry air entrainment and less moisture in the mid- and upper- levels. There will also be less instability around on Wednesday with MLCAPE values between 500-1000 J/kg. The net effect will be poor updraft growth, and fewer showers and thunderstorms. Temperatures on Wednesday will warm to near 90 with overnight lows around 70. .LONG TERM...(Thursday through Tuesday) Issued at 211 PM CDT Tue Jul 7 2020 The pattern changes by mid-to-late week as the 500- mb ridge becomes more amplified. This will place the Ozarks on the eastern periphery of the ridge as upper flow veers west- northwest. As multiple shortwaves ripple through the Central Plains and round the top of the ridge axis, a parade of MCSs will dig south out of Nebraska and Kansas. The first of these thunderstorm complexes will approach the region early Thursday morning along the MUCAPE gradient/Theta-e ridge. With the axis of the LLJ displaced across central Kansas, the thunderstorm complex will likely dissipate early Thursday morning as it moves into far eastern Kansas and western Missouri, perhaps leaving behind an MCV that could spark additional convective activity Thursday afternoon/evening. Temperatures on Thursday will again be near 90 with overnight lows near 70. By Thursday evening, another 500-mb shortwave should aid in the development of another MCS across Nebraska. The latest runs of the NBM and deterministic models (GFS, ECMWF, CMC) exhibit higher PoPs for Thursday night and early Friday morning as the MCS glides down the MUCAPE gradient and into our region. This will likely be our next best shot of widespread rain across the region. This nocturnal MCS has the potential to go severe. While the LLJ will remain modest across our western cwfa, CAPE/shear profiles will remain adequate/balanced enough for straight-line wind potential. Additionally, high PWATS (+1.75 inches) should result in very heavy downpours and frequent lightning. The Friday through Sunday timeframe will remain hot as the periphery of a closed 594-mb high builds across our western cwfa. Daily temperatures will range from the low-to-mid 90s, with heat index values between 100-105 F. Afternoon thunderstorm chances will likely be held down by strong capping, but nighttime MCS potential will remain possible, especially Saturday night into early Sunday as yet another shortwave digs south into the region. With so many MCS/MCVs floating across the region late this week and into the weekend, temperature forecasts have big bust potential. Nonetheless, a Heat Advisory (Heat Index values of 105 F) cannot be ruled out for parts of eastern Kansas and far western Missouri this weekend. The pattern looks very hot and dry by next week as that 594-mb closed high builds closer to the Four States region. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 603 PM CDT Tue Jul 7 2020 VFR conditions will continue into the evening and overnight hours across the TAF sites. A few fair weather cumulus will linger through the early evening hours with bases around 5 kft, before dissipating and leaving behind clear skies. Meanwhile, surface winds will remain light out of the east/southeast through the overnight hours. Isolated showers and thunderstorms will return tomorrow afternoon, but will remain very limited in coverage. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ SHORT TERM...Albano LONG TERM...Albano AVIATION...Perez