Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/08/21

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
837 PM CDT Wed Jul 7 2021 .UPDATE... Issued at 836 PM CDT Wed Jul 7 2021 Overall the forecast is doing fine so no major updates planned. Latest HRRR runs still bring some convection into and across the CWA from NW to SE late tonight. Temperatures look okay. && .SHORT TERM...(This Evening through Thursday Night) Issued at 322 PM CDT Wed Jul 7 2021 Cooler air and cu clouds have dominated the weather across the cwa this afternoon. Expect these cu clouds to dissipate into the evening as surface heating subsides. Otherwise, the ops models and hi-res models all point to two short wave troughs coming around the upper ridge to our west, affecting our region through Thursday night. For tonight, indications are that short wave/waa lift over the cooler air and mid level instability will bring scattered showers and storms across the region later tonight into Thursday. The second stronger short wave trough will drop in from the northwest Thursday afternoon and night. This wave will be more significant as there will be higher surface dewpoints, warmer temperatures, deeper instability and stronger deep layer shear. SPC has put a slight risk over much of our central and north central sd counties for this time. .LONG TERM...(Friday through Wednesday) Issued at 322 PM CDT Wed Jul 7 2021 Nearly steady state highs hovering a little below average for this time of year will switch to rising temperatures for Sunday through Tuesday, with above average temperatures continuing through the rest of the work week. Lows will remain in the upper 50s to low 60s. Unsettled weather, with off and on showers and thunderstorms, will continue into Saturday, with mainly dry weather Saturday night through the rest of the period. While most of the stronger storms will be to our east by 12Z Friday, we can`t rule out additional storms over mainly eastern SD. Another good chance will be over mainly central SD Friday night, as waves continue to rotate around the 500mb ridge over the southwestern U.S. Our attention will turn back to fire weather Sunday and beyond. At this point we have daytime rh values falling into the upper 20s to 30s across much of the area most days from Sunday through next Wednesday. On a positive note, winds will be mainly light. The exception will be with any thunderstorms, or potentially Monday afternoon into Tuesday as low pressure sets up to our west. && .AVIATION...(For the 00Z TAFS through 00Z Thursday Evening) Issued at 610 PM CDT Wed Jul 7 2021 Terminals KABR,KATY,KPIR,KMBG VFR skies/vsbys are expected overnight. However, as showers and thunderstorms move in after midnight, areas of MVFR vsbys due to rain is possible. MVFR cigs might also accompany the showers. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...TDK SHORT TERM...Mohr LONG TERM...KF AVIATION...TDK
Area Forecast Discussion
National Weather Service La Crosse WI
1030 PM CDT Wed Jul 7 2021 .SHORT TERM...(This evening through Thursday) Issued at 225 PM CDT Wed Jul 7 2021 Main question tonight is whether stratus will clear and/or fog will develop. RAP seems to have a decent handle on the short term cloud trends and so have favored that trend with this forecast. Fog for tomorrow morning is also a question. Light winds and low level moisture from recent rain suggest potential for fog, but if clouds do not clear, fog development could be inhibited. Have introduced patchy fog in SE MN tonight. Tomorrow another wave approaches so have introduced low pops for showers in the afternoon, although both coverage and amounts look light. Otherwise temperatures will be in the 70s. .LONG TERM...(Thursday night through Wednesday) Issued at 225 PM CDT Wed Jul 7 2021 Area remains under northwest flow aloft Friday into Saturday. An impulse embedded in the northwest flow is expected track into the Central Plain states. The trend has been slightly further southwest track with the impulse and associated surface features. This would keep higher instability and stronger moisture transport/convergence southwest of the forecast area. The 07.12z GFS suggest some moisture convergence/forcing over the western forecast area during the day Friday. Will continue shower/storm chances with higher chances west of the Mississippi River. Severe threat looks very low over the the shear and instability will be southwest of forecast area. Impulse/upper level trough digs over the Central Plains Saturday. Southern parts of the forecast area remain on the northern periphery of the impulse/surface low. With enough vertical motion and forcing over the southern parts of the forecast will allow for a small chance of showers to linger mainly over the southern portion of the forecast area. Temperatures will remain below normal Friday into the 07.12z GFS/NAM indicate 925mb temperatures cooling to plus 13 to plus 17 degrees celsius by 12 Saturday. High temperatures are expected to be mainly in the 70s. Main forecast concerns Saturday night through Wednesday are precipitation chances through the period. The 07.12z deterministic models continue to close off upper level low over the Upper Midwest/Great Lakes region Saturday night into early next week. The deterministic models indicate placement issues with the upper level closed off low. The latest EPS ensemble members show several ensemble members place upper level closed low southeast of the forecast area...however there are a few members further northwest with the placement. Confidence in placement of upper level closed low continues to be low...the ensemble members hint the upper level closed low could be southeast of forecast area and could keep most of the area dry Saturday night into Monday. At this time...with the discrepancies between the models/ensembles will continue with low chances during this period. Temperatures will be below normal Sunday into Monday...then begin to rebound Tuesday into Wednesday as southerly flow pattern develops to advect warmer temperatures aloft. && .AVIATION...(For the 06Z TAFS through 06Z Thursday evening) Issued at 1030 PM CDT Wed Jul 7 2021 Cigs: short term models and satellite trends suggesting the low cigs (ifr/mvfr) are going to hang around through at least Thu morning with RAP bufkit soundings and RH fields pointing to improvement (VFR) in the early afternoon. Looking to scatter out in the evening but low clouds could be on the return, at least for KRST, later in the day Friday. WX/vsby: weak upper level shortwave trough and some upglide on the 290:300 K sfcs has resulted in patchy to areas of drizzle. Vsby restrictions below 2sm at times. RAP and satellite trends suggest the drizzle should shift southeast of the TAF sites by 09z or so...could be even earlier at KRST. Looking ahead to tomorrow night, with a deep light wind layer, clearing skies and recent saturation, could have some fog development. How widespread/impactful it could be (if it develops) is not certain at this time. Will monitor and adjust forecast as needed. Winds: generally light (less than 10 kts) through the period. Mostly northern overnight/Thu, becoming more east Thu night. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...DMD LONG TERM...DTJ AVIATION...Rieck
Area Forecast Discussion
National Weather Service Buffalo NY
1024 PM EDT Wed Jul 7 2021 .SYNOPSIS... Showers and thunderstorms will be common across the area through Thursday as a stationary front lingers in the area. Low pressure will finally kick it eastward by Friday with a cool and mostly dry weekend in store. Warmer and more humid conditions return next work week. && .NEAR TERM /THROUGH THURSDAY NIGHT/... A quasi-stationary front is draped out just south of Lake Ontario late this evening with soupy air to the south of it and much cooler and less humid weather to its north. The flow aloft is directing showers and thunderstorms which developed earlier today across the boundary and into the cooler and more stable air mass. This is causing these storms to rapidly weaken, and diminishing any severe weather threat for tonight. As this convective wave slides to our east after midnight, expect a break in the action with only scattered showers and possibly a thunderstorm. This is captured well by the HRRR and some other mesoscale guidance. Strong large scale ascent coupled with PWAT values up to near 2 inches feeding northward from the tropicals and modest instability will allow for what looks like several surges of rainfall across the area on Thursday. Widespread 1-2 inch amounts of rainfall seem likely with this system as it slides through the area on Thursday. A slow wind down to showers seems likely Thursday night as a trailing wave keeps some degree of synoptic ascent plaguing the area into Thursday night. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... Tropical Storm Elsa will race northeast along the New England Coast Friday as it becomes captured and accelerated by an approaching mid latitude trough moving into the Great Lakes. Elsa will have no direct impact on our area. The upstream mid level trough and associated cold front will cross the eastern Great Lakes Friday, and may produce a few more scattered showers. The best rain chances will reside from the Southern Tier into the Finger Lakes and east of Lake Ontario, with lower chances across the Niagara Frontier. Extensive cloud cover and an early arrival of the cold front will keep thunder chances minimal. Highs will reach the mid 70s owing to cloud cover and the start of weak cold advection during the afternoon. A drier airmass will move into the eastern Great Lakes Friday night with any showers ending from west to east in the evening. Clearing skies and the arrival of a cooler/drier airmass will allow low temperatures to drop into the 50s overnight. Saturday and Saturday night high pressure will build into the Great Lakes, allowing for a return to dry weather and lower humidity. Highs Saturday will reach the mid to upper 70s away from the immediate lakeshores. Lows Saturday night will drop into the 50s in most locations and lower 60s along the lakeshores. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... The pattern will become more active again early next week as a mid level closed low evolves over the central US, forcing the frontal zone across the Ohio Valley back northward into the eastern Great Lakes. This will bring increasing rain chances early next week as humidity and instability move back into the region with increasing southwesterly return flow around high pressure anchored off the southeast coast. The GFS and subsequently the NBM looks too fast with the arrival of rain chances over the weekend, and our preference is to go with the slower ECMWF/GEM solution. With this in mind, a chance of showers will arrive in Western NY by Sunday afternoon, with a better chance of showers and a few thunderstorms Sunday night through Tuesday areawide as the approaching mid level closed low forces a low level boundary to stall near or over the eastern Great Lakes. The trough may move east of the area by next Wednesday, although a moist/unstable environment may still support a chance of a few scattered showers and storms in the afternoon along and inland of the lake breeze boundaries. Highs Sunday will reach the lower 80s for lower elevations away from the lakeshores, with still comfortable humidity. Monday through Wednesday highs will reach the low to mid 80s each day, and surface dewpoints will rise into the mid to upper 60s. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... Showers and possibly a thunderstorm are possible overnight, mainly before 06Z. Otherwise, increasing low moisture will result in lowering cigs and possibly some fog late tonight. Expect conditions to lower to MVFR or lower at many spots by daybreak. As a system tracks through the area Thursday, moderate to heavy rain will result, which will again generate widespread IFR conditions as it moves through. Outlook... Thursday night...IFR with showers, a few thunderstorms, and possibly some fog. Friday...Improving to MVFR/VFR with diminishing chances for showers. Saturday...VFR. A chance of showers over the far west. Sunday...VFR. Monday...VFR/MVFR with a chance of showers and thunderstorms. && .MARINE... A cold front will meander south of Lake Ontario overnight before moving back northward near its south shores on Thursday. Winds have diminished, allowing the small craft headlines to be dropped overnight. By Thursday a weak surface low will be advancing along this frontal boundary...with a relaxed pressure gradient maintain winds and waves below small craft thresholds. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...Fries NEAR TERM...Apffel/Fries SHORT TERM...Hitchcock LONG TERM...Hitchcock AVIATION...Apffel/Fries MARINE...Apffel/Fries
Area Forecast Discussion...Updated
National Weather Service Billings MT
911 PM MDT Wed Jul 7 2021 .UPDATE... Updated the forecast to cancel the Severe Thunderstorm Watch for Musselshell, Yellowstone and Treasure Counties. The Severe Thunderstorm Watch remains in effect for the rest of southeast MT until 11 PM MDT tonight. RMS && .DISCUSSION... Today through Thursday night... A couple of disturbances moving through the area this afternoon through tonight. First one doesn`t pack much punch but is producing a few very light showers and some wind gusts to 30 mph around Livingston. The cloud cover from this feature is helping to hold temperatures down just a bit from what they would be, and may cut 5 degrees off high temperatures across the southwest quarter of the forecast area. The second disturbance will push into the area from the west around 4pm or so and is expected to generate a squall line of high based thunderstorms that will cross the area this evening exiting the east in the early morning hours. Airmass and shear profiles are much different than yesterday, so the mode of storms today will be high based with damaging wind gusts being the main threat. Last several runs of the HRRR showing a wall of wind moving into the Billings area between 5 and 7pm with gusts in the 40 to 60 mph range, and possibly as high as 75mph if everything plays out just right. The aforementioned cloud cover reduced temperatures may play a role in just how strong those winds get. Frequent lightning, brief rainfall, and maybe some small hail are also possible with these storms. Thursday looks drier with less convective activity. Models are taking the next disturbance well north of the area which allows downslope west to northwest winds to scour out some of the moisture that was in place the past week or so. That pushes RH values well into the teens to single digits, while temperatures stick in the mid to upper 90s. At this time winds look light enough to preclude any fire weather highlites but will keep an eye on that. Thursday night northeast winds try to surge back into the area from the northern plains, bringing moisture and cooler air back int the area for Friday. Along this resurgent boundary there could be a few showers/thunderstorms develop, mainly from Rosebud county east. Main message for the short term, be prepared for the possibility of damaging winds with line of storms that moves through this evening. Chambers Friday through Wednesday... The extended period continues to look fairly active, at least to start the period, with some potential for late period activity as well. Friday and Friday night should see a chance for widespread precip for the region, as an upper level trough crosses the region, flattening the ridge. Precip is expecte to linger in the east for much of the day Saturday. The upper level ridge is quick to rebuild over western Montana Saturday and shift eastward Sunday, bringing a return of dry conditions and hot temperatures. An area of low pressure is progged across southern Canada Sunday night, which should flatten the ridge again. The pattern locks fairly flat from this point through midweek, allowing potential for a more progressive, active pattern to re-emerge. A cold front associated with the Canadian low is expected to dropping through the area Monday, bringing slightly cooler temps, and a chance for showers and thunderstorms. Additional pieces of energy will keep temps a little cooler than those seen over the weekend, and could bring additional precip potential. Currently ensembles and models look fairly dry for the latter half of the extended period, so grids are mainly dry this far out. Expect highs in the 80s to low 90s for Friday and Saturday, with with 90s to a few degrees above 100 for Sunday. Upper 80 and low 90s are expected for the beginning of next week. Overnight lows look to be in the 50s and 60s for most nights. Gilstad && .AVIATION... VFR conditions will prevail for the next 24 hours. A few thunderstorms are drifting through the southern mountains early this afternoon, slowly diminishing as they move eastward. Main aviation threat with this activity will be localized gusts to 35kts. A squall line is expected to develop over the western foothills (KLVM) late this afternoon and spread eastward into the KBIL area between 23-01z and into KMLS 03-05z. Thunderstorms along this squall are expected to produce wind gusts of 40 to 60kts. Local MVFR visibility is possible near precipitation areas associated with the squall line. Conditions will improve quickly behind the line. Chambers && .PRELIMINARY POINT TEMP/POPS... Thu Fri Sat Sun Mon Tue Wed ----------------------------------------------------------- BIL 064/097 063/088 059/091 063/099 066/093 063/092 063/092 21/U 14/T 10/U 00/U 11/U 11/U 11/U LVM 055/094 054/085 052/092 056/097 057/092 055/091 055/091 21/H 14/T 10/U 00/U 11/U 11/U 11/U HDN 061/098 061/091 056/092 059/100 062/096 060/095 060/094 31/U 24/T 20/U 00/U 00/U 11/U 11/U MLS 065/095 062/087 061/088 063/098 065/094 062/092 062/091 41/U 24/T 31/U 01/U 11/U 11/U 11/U 4BQ 065/095 063/088 061/086 061/095 066/095 063/091 063/090 41/U 24/T 42/T 01/U 01/U 11/U 21/U BHK 060/093 058/086 057/085 058/094 060/093 058/088 058/088 52/T 24/T 52/T 01/U 11/U 11/U 21/U SHR 058/094 057/086 053/087 055/095 059/092 057/091 057/088 21/U 14/T 31/U 01/U 11/U 12/T 22/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Severe Thunderstorm Watch 346 in effect until 11 PM MDT this evening FOR ZONES 31>33-36-37-57-58-138-139-169-171. WY...None. && $$
Area Forecast Discussion
National Weather Service Columbia SC
804 PM EDT Wed Jul 7 2021 .SYNOPSIS... Scattered showers and thunderstorms from Elsa will begin to increase across the region this evening with widespread rain overnight into Thursday morning. One to three inches of rain is expected with locally higher amounts especially across the eastern Midlands. After Elsa, a typical summer-like pattern begins with afternoon showers and thunderstorms possible each day and temperatures right around average. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... At 00z, Tropical Storm Elsa is located over southeast Ga moving to the north. Widespread rain with embedded thunderstorms over coastal Ga moving north toward the region. Radar widespread rain ahead of the center spreading north along coastal Ga toward South Carolina and east central GA. Latest meso-analysis showing moderate CAPE across the region. Increasing 0-1km shear/SR helicity expected across the east and SE Midlands/CSRA during the evening and overnight as the tropical storm approaches. This is supported by latest Rap and HRRR guidance. SPC has issued a Tornado Watch for the southeast portion of our CWA until 5am tonight. So threat for a few embedded brief tornadoes in the region overnight. Previous forecast appears on track with pops increasing to categorical as the Elsa moves into the region. Locally heavy rainfall will be possible. Increased convective coverage and high rain rates will lead to rainfall amounts between 1 to 3 inches with highest amounts in the southeast, locally up to 5 inches in some locations. With cyclone moving fast, and Flash Flood guidance high, held off on Flood Watch. Observations are indicating wind gusts to tropical storm strength well to the east of the center near coastal Ga. Although the strongest winds will probably remain in the SC coastal plain and instability main weaken late tonight, gusts to around 40 mph possible mainly in the eastern Midlands near I-95...and Lake Marion overnight. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/... Elsa will lift northeastward away from the region Thursday night with some possible lingering residual showers across the forecast area. On Friday, the upper trough that will help move Elsa up the eastern seaboard will move southeastward into the Ohio Valley as some shortwave energy crosses our area during the afternoon hours of peak heating. PWATs will remain relatively high in the wake of Elsa with values around 1.7-1.9 inches, which combined with diurnal heating and some weak shortwave energy should lead to scattered or potentially numerous showers and thunderstorms. Saturday and Saturday night, the upper trough will lift north of the region in response to a much deeper upper trough digging into the middle of the country. 500mb flow should back a bit more southwesterly and expect lower chances of diurnal convection Saturday afternoon with no real trigger for convection in the absence of a shortwave. Temperatures during this period will be near normal with highs in the lower 90s and lows in the lower 70s. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... A return to a more typical summer pattern is expected late in the weekend into the middle of next week. The 500mb pattern will return to one that is dominated by the western Atlantic upper ridge late in the period. The positively tilted upper trough over the Ohio/Mississippi Valleys will remain nearly stationary Sunday and then begin to lift northward into the Great Lakes region by Monday as the strong upper ridge over the western CONUS remains entrenched and the western Atlantic ridge builds westward into the Carolinas and southeastern states. Again, in the absence of any significant shortwave energy or triggers for forcing, generally expect a typical summer pattern with daily diurnally induced scattered showers and thunderstorms. PWAT values will remain near to slightly above normal during this period with ensembles continuing to show a high probability of values greater than 1.5 inches. Rain chances on Sunday may be slightly higher due to the potential for a surge in moisture moving inland from the coast as the upper ridge builds over the western Atlantic. Temperatures will also remain near normal with highs in the lower to mid 90s and lows in the lower to mid 70s. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... MVFR and IFR restrictions are expected for the majority of the upcoming period as Tropical Storm Elsa makes its way through the region. Currently, TS Elsa is located over south Georgia, and is making its way northeastward towards central SC. Ahead of it, a broad shield of rainfall is approaching the region gradually, with widespread showers preceding that right now. These will make their way over the region over the coming hours, briefly creating cig/vis restrictions across the area. I have TEMPO groups at all sites to account for this. MVFR cigs and IFR cigs are then expected to quickly develop with Elsa`s approach tonight. These should first develop at AGS/DNL between 02z and 04z, with IFR cigs developing shortly thereafter. The timing is similar at CAE/CUB/OGB, with MVFR developing around 03z-05z, with IFR expected thereafter. Widespread, consistent rainfall is expected to then push into the TAF sites beginning at AGS/DNL around 06z (maybe slightly earlier), with rain beginning at CAE/CUB/OGB around 07z. I expect vis to be restricted in the 2sm-3sm range by the rain during this time as well. Winds will likely be breezy as the center of circulation approaches between 10z and 12z, with gusts around 25 knots at OGB, 20 knots at CAE/CUB, and 18z at AGS/DNL. In short, tonight is not the best night to fly. By tomorrow morning, the center will be pulling away from the region, but guidance only gradually removes CIG restrictions. We should see things improve to MVFR by ~13-15z, with VFR coming by 18z. Rain will be quick to move on out of the region after the center passes, with some afternoon showers possible again. EXTENDED AVIATION OUTLOOK...Tropical moisture will continue to be in place in the wake of Elsa, leading to afternoon diurnal showers and thunderstorms. Areas of patchy fog cannot be ruled out during the morning hours starting this weekend, especially at the typically fog prone locations. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...Lake Wind Advisory from 11 PM this evening to 8 PM EDT Thursday for SCZ031-037-038-137. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM... AVIATION...
Area Forecast Discussion
National Weather Service Cheyenne WY
616 PM MDT Wed Jul 7 2021 .UPDATE... Issued at 604 PM MDT Wed Jul 7 2021 Fuels for FWZ 304 (southwest Carbon County) were upgraded to critical this afternoon. Went ahead and added FWZ 304 to the Red Flag Warning for Thursday and Fire Weather Watch for Friday. && .SHORT TERM...(This evening through Thursday night) Issued at 215 PM MDT Wed Jul 7 2021 Hi-Res guidance has continued to suggest thunderstorm development along the lee trough north of the Pine Ridge this afternoon headed into the evening which prompted SPC to expand their Day 1 Outlook this morning into the Nebraska Panhandle with a Slight Risk area. Latest satellite imagery has shown cumulus development since 18z across Converse and Niobrara Co in Wyoming with a few lightning strikes and fairly weak radar echos so far. Expecting additional attempts at CI over east-central Wyoming this afternoon out ahead of the shortwave riding the northern edge of the ridge over the four corners region. Upwards of 1000 J/kg of MLCAPE is available over the Nebraska Panhandle with 35-45 kts of 0-6km shear as storms move that way later this afternoon. This should support supercellular modes with any storms that do develop with fairly straight line hodographs supporting initial storm splits. Any right-movers that do sustain themselves afterwards will move southward into the favorable environment near Sioux and Dawes Co in Nebraska with hail and downburst winds being the main threat. Cannot rule out a possible tornado with decent directional shear present, however LCLs should be fairly high. Severe potential should be mostly over with by 9 PM MDT, however a few showers with the shortwave passage are possible across Niobrara Co later this evening. Thursday will be warm across most of the region with afternoon temperatures 90s for most spots. Locations across the North Platte River Valley from Torrington and east could see triple digits during the afternoon. Farther west, Red Flag Warnings are in effect for the Laramie Range and areas west of the mountains towards south-central Wyoming. RHs 12-15 percent look likely with gusty winds, however upper level cloud cover could prevent a few spots from reaching their MaxT potential. Hi-Res guidance has hinted at the potential for isolated showers in the afternoon, however kept PoPs fairly low as plenty of uncertainty remains. .LONG TERM...(Friday through Wednesday) Issued at 215 PM MDT Wed Jul 7 2021 Much of the forecast remains on track through this weekend with minor variations within the overall pattern. Upper level ridging is expected break down with a series of shortwave troughs digging easterly across the CWA out ahead of the frontal boundary digging southward on Friday. As a result, precipitation chances remain elevated and widespread on Friday with plenty of moisture advecting into the region. As we move into the early part of the weekend, the pattern remains fairly active with the development of a positive tilted trough extending through the Great Plains. Should see a cool down in the initial weekend temperatures with most areas never really peaking above 80 degrees as the frontal boundary continues tracking southward. Combined with a series of shortwaves expected to periodically pulse across southeastern Wyoming and the Nebraska Panhandle and a continued swath of moisture advecting into the region, will see an extention for widespread precipitation chances through 00Z on Sunday. Severe potentials appear to be limited both Friday and Saturday with CAPE values struggling to raise above 500 J/kg on either day. Nevertheless, should see a lightning strike or two associated with any system able to develop. Looking into the late weekend and into next week, quieter weather expected as a ridge of high pressure builds across the CWA, returning the region to a warm and dry pattern. In addition, will start to see an uptick in the temperatures under this feature, with daytime highs in the upper 80s and mid-90s. Current model guidance indicates some shortwave disturbances within the upper level ridging, providing slight chances for afternoon thunderstorms. However, any convective initiation will ultimately be limited as subsidence is expected to prevail with upper level ridging remaining overhead and moisture advection effectively cut off. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 433 PM MDT Wed Jul 7 2021 Current radar imagery has a severe thunderstorm tracking southeasterly across Goshen County, north of Torrington. Radar estimated hail has reached close to 2.5 inches. Expecting convective cells developing off the outflow to drop south/southeasterly into the northern to northeastern portions of the Nebraska Panhandle, and digging to the southeast across KAIA through the evening hours. Could see some continued strong to severe cells with decent environmental conditions conducive for cell growth as MLCAPE values remain around 1000 J/kg and 40 kts of 0-6 km shear. Main threats will be hail up to 2 inches and strong downburst winds. However, cannot rule out a tornado or two associated with any convection. HRRR guidance has been fairly accurate with storm motion and development, with a slight westward shift in the location. Due to the uncertainty associated with the exact location of any convection for the remainder of today, went ahead and and left VCTS across KBFF, KCDR, and KAIA. Although, KCDR seems less likely. VFR conditions expected through the remainder of the forecast period with maybe some gusty conditions expected tomorrow. && .FIRE WEATHER... Issued at 215 PM MDT Wed Jul 7 2021 Above normal temperatures return to the area Thursday and Friday that will lead to fairly dry conditions across southeast and south-central Wyoming. Afternoon RHs will drop to 12-15 percent each afternoon with wind gusts around 30 MPH out of the west. Red Flag Warning are in effect Thursday for most locations along and west of the Laramie Range where fuels have dried out as of early July. Additionally, a Fire Weather Watch has been issued for Friday where winds are expected to be slightly stronger ahead of a cold frontal passage. Slightly cooler temperatures on Saturday will bring some relief, however areas west of the Laramie Range look to remain dry again Sunday and headed into early next week. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Red Flag Warning from 11 AM to 8 PM MDT Thursday for WYZ301-302- 304-305-307>309. Fire Weather Watch from Friday morning through Friday evening for WYZ305-307-308. NE...None. && $$ UPDATE...GCC SHORT TERM...MB LONG TERM...MD AVIATION...MD FIRE WEATHER...MB/MD
Area Forecast Discussion
National Weather Service El Paso TX/Santa Teresa NM
544 PM MDT Wed Jul 7 2021 ...Update for 00Z TAF Cycle... .AVIATION...00Z TAF CYCLE VFR conditions expected to prevail through forecast period. VCTS included for KLRU/KDMN until 03Z this evening as scattered thunderstorms subside. Skies beginning SCT-BKN070CB, becoming FEW100 after 06Z tonight. Winds 050-080 at 08-12KT subsiding to 04-08KT overnight. TS coverage will be limited to Gila Mountains on Thursday with no threat to local terminals. Light SE surface winds will make for a good flying day. && .PREV DISCUSSION...200 PM MDT Wed Jul 7 2021... .SYNOPSIS... Thunderstorm chances all but disappear for Thursday and Friday, except for the Gila. Then on Saturday, moisture returns bringing thunderstorm chances back into the picture until mid-week next week when drier air lowers storm chances yet again. Temperatures will generally be in the 90s with the hottest days Friday and Saturday. && .DISCUSSION... .SHORT TERM...Today through Tomorrow... An upper level ridge of high pressure will continue to linger across the Four Corners. Weakness along the eastern periphery of the ridge coupled with orographic lift and diurnal heating will produce showers and thunderstorms across the mountains first before spreading to the the inland areas. I`m not expecting significant widespread showers and storms as was the case yesterday. However, latest HRRR does suggest that much of the storms will be confined to areas along the Arizona/New Mexico border with a few pop-up storms east of the Rio Grande As with any storms, gusty winds and heavy down pours are expected. The winds this afternoon will be light to moderate and generally from the east with the high temps slightly on the cooler side. Active weather should diminish by early this evening as we loose daytime heat suggested by latest hi-res models. However, I can`t rule out a lingering storm or two passing through before midnight as with the case from the previous nights. Quiet will be in store the rest of the night with a few clouds hovering over our CWA. The winds will become light to light and variable during the overnight hours. With clouds in place, the lows on Thursday morning will be on the warm. Fewer storm coverage is anticipated for Thursday as the upper level ridge begins to strength over our area. Any storms that do occur will be across the high terrains such the Gila Mountains. Much of the area will be relatively dry with drier air in place under the ridge. && .LONG TERM... Rain chances will be dependent on the position of the summertime upper high and the moisture stream rotating clockwise around it. Friday will be a dry day with the high west of the Four Corners with relatively dry air circulating into the CWA and PW (Precipitable Water) values dropping below an inch. This will leave only an outside chance for the Gila. The high decides to vacation over Vegas and decides to party there for the remainder of the long-term period. This will keep a relatively moist flow over the area through Monday with PW values between 1-1.25". Storm chances will therefore return on Saturday though with mountain areas favored. Of note, a trough will close off into a low over the mid-west, and its trailing trough axis may enhance thunderstorm chances some for Sunday night. Otherwise, it will be the typical monsoonal pattern of scattered mountain storms with lowland storms forming off outflows in the late afternoon and evening. The high continues its summer vacation over Vegas by Tuesday, but it will expand its influence over NM and Far West TX. As it does so, some drier air will arrive dropping PW values below an inch to finish out the period. Rain chances will drop accordingly. Kept low pops in for now, but if the present pattern holds, they may need removal for Tuesday and especially Wednesday. Temperatures during this period will continue to be at or below normal. The drier days will be on the warmer side. El Paso will be close to adding one more 100 to its 2021 total on Saturday. We drop back below normal Sunday, then start warming again mid-week as moisture departs. && .FIRE WEATHER... Showers and thunderstorms are possible this afternoon into early this evening before drier weather begin to move in across the area. Expect Thursday and Friday to be mainly dry except with the possibility of the Gila mountains on Friday afternoon. Moisture will return this weekend into next week bringing another chance for showers and thunderstorms. The Min RH`s will be above 30% today with it dropping to below 30% on Thursday and Friday. The Min RH`s for this weekend into first half next week should creep back into the 20 to 30% across the lowlands and 40 to 50% in the mountains. The vent rate will poor to good through the up coming weekend and into next week. && .PRELIMINARY POINT TEMPS/POPS... El Paso 70 93 72 97 / 10 0 0 0 Sierra Blanca 62 86 63 89 / 0 0 0 0 Las Cruces 66 91 68 96 / 20 0 0 0 Alamogordo 64 91 67 96 / 20 0 0 0 Cloudcroft 46 71 50 75 / 20 0 0 0 Truth or Consequences 67 92 71 96 / 20 0 0 0 Silver City 61 86 65 91 / 30 0 10 10 Deming 64 93 66 98 / 30 0 0 0 Lordsburg 67 92 69 97 / 30 0 0 0 West El Paso Metro 71 93 72 97 / 10 0 0 0 Dell City 65 91 66 94 / 0 0 0 0 Fort Hancock 68 94 69 97 / 10 0 0 0 Loma Linda 64 85 66 89 / 0 0 0 0 Fabens 70 94 71 97 / 10 0 0 0 Santa Teresa 67 91 68 96 / 20 0 0 0 White Sands HQ 69 90 71 95 / 20 0 0 0 Jornada Range 66 90 68 95 / 20 0 0 0 Hatch 66 92 68 98 / 20 0 0 0 Columbus 68 91 69 96 / 20 0 0 0 Orogrande 65 90 68 94 / 10 0 0 0 Mayhill 52 79 55 83 / 20 0 0 0 Mescalero 50 81 55 85 / 20 0 0 0 Timberon 49 77 53 81 / 10 0 0 0 Winston 55 85 58 91 / 20 0 0 10 Hillsboro 63 89 66 94 / 30 0 0 0 Spaceport 64 90 67 95 / 20 0 0 0 Lake Roberts 56 88 59 93 / 30 10 10 20 Hurley 60 89 63 94 / 30 0 0 0 Cliff 58 95 61 100 / 20 20 20 20 Mule Creek 62 90 66 95 / 30 20 20 20 Faywood 63 87 66 93 / 30 0 0 0 Animas 65 92 67 98 / 30 0 0 0 Hachita 64 91 66 96 / 20 0 0 0 Antelope Wells 66 90 67 96 / 20 0 0 0 Cloverdale 63 86 65 92 / 20 0 0 0 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...None. TX...None. && $$ 32/34/30
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
636 PM CDT Wed Jul 7 2021 .AVIATION... A moist tropical airmass remains over the TAF sites tonight through Thursday night. SHRA are possible through the period and have VCSH at KSAT/KSSF at all times being closer to the center of the system with VCSH at KAUS this evening and on Thursday. Have no mention at KDRT, although cannot rule out VCSH early this evening and on Thursday. Only ISOLD TSRA are possible and left out any mention at the sites. CIGs are already at MVFR at KSSF and will drop to MVFR at KSAT this evening and KAUS closer to midnight, then spread to KDRT overnight. CIGs will drop to IFR at the I-35 sites overnight, possibly LIFR with restrictions to VSBY early in the morning. CIGs slowly rise to MVFR by midday with DRT becoming SCT. There could be brief breaks at the I-35 sites for CIGs to briefly become VFR in the afternoon. CIGs will lower to IFR Thursday night. Easterly winds of 6 to 14 KTs will prevail with a few gusts to 25 KTs possible mainly at KSAT/KSSF. && .PREV DISCUSSION... /ISSUED 247 PM CDT Wed Jul 7 2021/ SHORT TERM (Tonight through Thursday Night)... At 18z RAP analysis and surface obs depicted a sfc low pressure center over the east half of the CRP CWA, nearly vertically stacked with it`s 500 mb counterpart. Onshore flow and strong moisture convergence are bringing impressive rainfall to portions of the Coastal Bend, but at this time the more widespread rain has struggled to push into our Coastal Plains counties. Some "popcorn shower" activity has impacted the I-35 corridor and portions of the Hill Country but even the heavier showers are only producing a quarter inch or so of rain before moving on to the west. Temperatures remain seasonally cool, in the upper 70s to mid 80s for the most part though warmer in Val Verde County where they will creep into the 90s again. Model consensus drifts the center of the system ever-so-slowly inland tonight through Thursday night, although there may be some wobbles back eastward at times. Similar conditions to today will remain, with highest rain chances locked closer to the gulf but scattered shower and isolated thunderstorm activity continuing across much of our area. The exception will be the southern Edwards Plateau where distance from the low as well as lower PWATS will keep chances for rain suppressed. Although CAMS have backed off some on heavy rain potential for our area over the next 24 hours, some of the more widespread and/or heavier rain may reach our Coastal Plains counties from time to time. The HRRR remains bullish on overnight QPF across the far southeastern corner of the CWA, for example. The Flash Flood Watch will remain in effect for Karnes, DeWitt, and Lavaca through Friday morning, but areas as far north as San Antonio, New Braunfels, and La Grange should still be in heightened awareness mode through the end of the week as a precaution since it can`t be ruled out that some heavier rain sneaks a little further north than the current forecast suggests and some of these areas are already rather saturated. The watch may at some point need to be extended into the daytime Friday as the NAM and WRF-FV3 depict strong onshore flow and resultant banding of heavy rain after midnight Thursday night into Friday morning. This is not supported by the rest of the model suite, but is worth watching as a potential primary period for additional flash flood risk in the southern half of our area. LONG TERM (Friday through Wednesday)... To start the long term the first issue will be the above mentioned strong onshore flow resulting in the band of heavier rainfall in the NAM and WRF-FV3. If this does verify then the heavier hand of rainfall looks to work west towards the Rio Grande and Eagle Pass through the middle part of Friday with more scattered showers and thunderstorms further north. Interestingly the new 12z ECMWF delays this band of heavier rainfall until Friday evening, but just like the NAM/WRF-FV3 for the morning hours, the EC is an outlier to the drier GFS, Canadian, and NAM for the second half of Friday. Synoptically going into the weekend the ridge across the Four Corners region will try to build back into Texas while the trough of low pressure that has been bringing the area rain either shrinks back west into Mexico (according to the ECMWF and NAM) or moves towards the Upper Texas Coast (based on the Canadian and GFS). Either way it looks like the rain chances, and especially the heavy rain chances, continue to be relegated to mainly the Coastal Plains through the weekend with some sunshine peaking out for folks across the Edwards Plateau and the Hill Country. As the weekend transitions into next week the next large trough of low pressure will work down across the Central Plains and Great Lakes Region splitting the ridge across the Western U.S. and the one over Florida in half. This will be enough to drag a boundary (hesitant to call it a cold front) down into Texas. Models differ on where the boundary will set up with the Canadian bringing it south to the I-10 corridor, while the GFS brings it into the Hill Country, and ECMWF keeps it north. Regardless, it should be close enough to enhance chances for isolated showers and thunderstorms again for the day on Monday. By Tuesday morning the trough over the Great Lakes ejects to the northeast and the pair of ridges work to build back over South Central Texas. While the moist southeasterly flow off the Gulf will still be in place the pattern looks to settle down into more of a typical summer time pattern for the area - afternoon sea breeze showers and thunderstorms mainly along the Coastal Plains with mostly sunny skies elsewhere. The good news is that temperatures, even with the ridge building back in will continue to be below normal, in the upper 80s and lower 90s. Typically we should be in the mid to upper 90s this time of year. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 72 86 73 86 74 / 20 50 20 50 10 Austin Bergstrom Intl Airport 71 85 72 86 73 / 20 50 30 50 10 New Braunfels Muni Airport 73 84 73 86 74 / 30 60 30 60 20 Burnet Muni Airport 70 85 71 85 72 / 10 30 20 40 10 Del Rio Intl Airport 74 91 75 90 74 / 10 20 30 50 30 Georgetown Muni Airport 71 85 72 85 73 / 20 40 20 50 10 Hondo Muni Airport 72 85 73 84 73 / 20 40 30 70 20 San Marcos Muni Airport 71 84 72 86 73 / 30 60 30 50 10 La Grange - Fayette Regional 74 84 74 87 76 / 30 60 30 60 20 San Antonio Intl Airport 73 84 73 85 74 / 30 50 30 70 20 Stinson Muni Airport 74 85 74 86 76 / 30 60 40 70 20 && .EWX WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch through Friday morning for De Witt-Karnes-Lavaca. && $$ Short-Term/Aviation...04 Long-Term...Platt
Area Forecast Discussion
National Weather Service Grand Rapids MI
939 PM EDT Wed Jul 7 2021 LATEST UPDATE... Update .SYNOPSIS... Issued at 258 PM EDT Wed Jul 7 2021 - Strong to severe storms precede cold front this evening - Fair Weather interlude followed by return of showers && .UPDATE... Issued at 938 PM EDT Wed Jul 7 2021 It would seem the potential for strong to severe storms has greatly diminished this evening. While it is true the MU cape is expected to say between 1000 and 1500 this evening and it actually rises to over 2000 kg after 3 am as the cold front gets closer. On the other hand there is not much of a low level jet at this moment in our area but by 1 am there is 25 kt low level jet north of HTL, aimed at PLN. that puts southwest Michigan in the speed divergence at low levels. There is decent FG in the 850 to 700 mb layer over northern MI during the early morning hours of Thursday. Meanwhile the upper trough continues to deepen as a 70 knot jet core digs down the back side of the deepening shortwave trough (over western WI at 8 am). That will cause the low level jet to redevelop near or south of I-96 toward morning. The result of all of this will be the area of showers from here west will slowly fall apart over the next few hours in favor of convection north of Route 10 and east of I-75 (where the low level jet focuses). As the primary cold front head this way we should see an area of showers/thunderstorms develop near Lake Michigan then head east cross the CWA around sunrise. Due to the low level inversion in the boundary layer any thunderstorms would be elevated so I do not see much of severe threat overnight. The bottom line is scattered showers and isolated thunderstorms will be around till after midnight. Then after 3 am or so expect some showers and thunderstorms to develop west of Muskegon and that area will cross our CWA between 4 am and 10 am. && .DISCUSSION...(This evening through next Wednesday) Issued at 258 PM EDT Wed Jul 7 2021 - Strong to severe storms precede cold front this evening We expect the conditions for strong to severe storms to continue through this evening across the southeast forecast area in the warm sector ahead of advancing cold front. Sfc based CAPE of 2500 to 3500 J/kg should persist in this area until diurnal loss of heating. Storm type should be primarily multi-celled clusters as deep layer shear is less than 30 knots across southern zones. The exception would be for some transient supercells further north where shear is greater than 35 knots, and especially in the vicinity of outflow boundaries. The severe threat should diminish after sunset as instability decreases, but some strong storms and a heavy rain threat could persist overnight and into Thursday morning along the cold front. The front should clear the eastern zones by afternoon with a cooler and much drier air mass moving in. - Fair Weather interlude followed by return of showers Canadian high pressure brings a welcome spell of cooler and drier weather late Thursday into Saturday. A blocking pattern develops over the weekend with Michigan in between an upper low to our west and an upper high over the SE CONUS. As the upper low slowly moves northeast, an overrunning pattern could bring some showers on Saturday. A warm front could bring higher chances of showers and thunderstorms across Lower Michigan from late Sunday into early next week. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 743 PM EDT Wed Jul 7 2021 There is a large area of IFR cigs near and just north of I-96. That is the cold air dome slowly trying to sink south and west over time. The problem is through is that there is another wave on the front pushing eastward. Given there is a large area of showers just west of Lake Michigan moving east associated with that wave on the front. My thinking is the low clouds will spread over our CWA within the next few hours and that is supported by the RAP model cloud forecast. Once the low clouds move in they may be hard to push out since the front does seem to want to be farther south tomorrow. As for convection, the initial wave of convection is moving out of the area but a second area is following it. The question becomes is there enough instability to create thunderstorms. It seems while the storms would be elevated in nature, there surly could be. However given this is at night when this is coming through, seems showers are more likely than thunderstorms. So I did not put VCTS in any of the TAFs overnight. The time frame for this second wave of showers to move through is roughly 02z to 09z. The bottom line is I expect all of our TAF sites to be either IFR or low MVFR by morning and I do not seem much improvement during the day Thursday. && .MARINE... Issued at 256 PM EDT Wed Jul 7 2021 Wind gusts over 30 knots in thunderstorms are possible through this evening across Lake Michigan south of Grand Haven. North winds can be expected on Thursday and may gust to 25 knots with some choppy waves along the Big and Little Sable points. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ UPDATE...WDM SYNOPSIS...Ostuno DISCUSSION...Ostuno AVIATION...WDM MARINE...Ostuno
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1052 PM EDT Wed Jul 7 2021 .SYNOPSIS... Tropical Cyclone Elsa will pass quickly north through Georgia and the Carolinas through Thursday resulting in gusty winds and heavy showers for parts of the piedmont. Following this, an active mid- summertime pattern will develop by the weekend with a chance for showers and pulse thunderstorms each day into the early part of next week. && .NEAR TERM /THROUGH THURSDAY/... As of 1050 PM: Another area of showers pushing into the southern/southwestern zones, slowly expanding north. The rest of the area is only seeing isolated showers attm. The 00z guidance that is coming in, and the latest HRRR all show similar track/evolution of Elsa as before, so the forecast looks on track. Shower chances ramp back up overnight as Elsa tracks toward the area. Expect widespread showers and isolated storms across most of the area. With the center of Elsa tracking closer to our area, expect wind speed and gusts to pick up late tonight and continue through the morning. Strongest winds will be across and east of the I-77 corridor, but nothing close to tropical storm winds expected for our area as the better wind field will be east of the track. Heavy rain continues to be the main threat, especially with the track closer to our area. PW values over 2 inches are expected to move in from the south. The axis of heaviest QPF has shifted west but the heaviest rainfall is expected to be to our east. The heaviest rainfall for our area is expected over Union, NC with a quick drop off east and north of there. Can`t rule out some isolated flooding over the eastern portion of the CLT Metro area. However, potential coverage and overall flood chance precludes the issuance of a watch for now. Finally, the track of the storm is still not the most favorable for tropical tornadoes. However, the guidance does indicate a brief uptick in 0-1 km helicity and shear as the center moves by. Surface, mixed level, and most unstable CAPE are all at a minima during that time as it will be near the 12Z time frame. This limits the overall threat, but will need to be watched in real time. Elsa quickly moves northeast away from the area Thursday afternoon, bringing an end to the tropical threats. Precip chances taper off quickly from west to east as well. There will be lingering low level moisture and developing instability with heating during the afternoon. So scattered diurnal convection could return. Highs will be below normal with morning clouds and precip, but muggy conditions will continue. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... As of 1245 PM EDT Wednesday: Elsa`s circulation is progged to be downstream of even the NE cwfa by sunset Thursday leaving our sensible wx to just dissipating diurnal mountain deep convection. The next synoptic scale feature of limited interest to affect the region will be a weak cold front which is progged to ripple through on Friday. With at least some frontal band forcing present within a plume of developing moderate instability cvrg of storms should blossom to numerous as the day wears on. With subtle troughiness in the upper pattern continuing into Saturday along with developing lee trough, there would seem to be little to inhibit deep convective cvrg becoming numerous again. Temperatures through the period will be within a category of the mid-summer climo. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... As of 100 PM EDT Wednesday: Upper heights atop the SE CONUS will begin rising on Sunday and continue into Monday as blocking Bermuda hipres builds wwd. Within the decent southerly convergent flow between the Plains system and offshore anticyclone, expect daily diurnally enhanced numerous showers and thunderstorms. With the axis of the stout anticyclone pressing a bit further west on Tuesday and Wednesday, more in the way of solid Piedmont lower 90s for max temperatures is expected, and daily diurnal thunderstorms should become more scattered in nature. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... At KCLT and elsewhere: a lull in convection is expected over the next few hours, before another round of mainly tropical rain bands/showers begin to work in from the south with the approach of Elsa. Going with VCSH this evening, then prevailing SHRA with Elsa. Winds will gradually back from southerly to easterly, then northeasterly overnight, as cigs lower. Guidance has trended less pessimistic on cigs, but still showing MVFR to IFR possible Thursday morning. The heaviest rain bands should affect KCLT, mainly in the 09-15z time frame. Winds will be gustiest at that time as well. By midday, Elsa will begin to exit to the east/northeast and we should see improving cigs and a break in precip. Afternoon showers and tstms will be possible, mainly across the mountains, being more isolated to the east. Will carry PROB30 for TSRA for tomorrow aftn. Winds will become lighter and turn to NW, then SW in the aftn. Outlook: An unsettled pattern, with mainly diurnal convection and morning stratus/fog, is expected to persist into the weekend. Confidence Table... 03-09Z 09-15Z 15-21Z 21-00Z KCLT High 100% Low 59% Med 77% Med 73% KGSP High 97% Low 52% Med 61% High 100% KAVL High 94% Low 45% Med 67% High 100% KHKY High 100% Med 60% Med 65% Med 71% KGMU High 95% Low 46% Low 57% High 100% KAND High 87% Med 65% Med 63% 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...CSH NEAR TERM...ARK/RWH SHORT TERM...CSH LONG TERM...CSH AVIATION...ARK
Area Forecast Discussion...CORRECTED
National Weather Service Gray ME
1035 PM EDT Wed Jul 7 2021 .SYNOPSIS... Low pressure will form along a cold front Thursday bringing potentially heavy rain Thursday night into Friday morning with a focus on the mountains. Tropical Storm Elsa will be in the vicinity of Cape Cod Friday, accelerating towards Nova Scotia Friday night potentially bringing another round of heavy rainfall. Drying trend is expected over the weekend as weak high pressure builds over the Northeast. Ridging is expected to continue to build into midweek next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 1030 PM Update...Little change to the going forecast at this time. Have blended in the HRRR a bit more to take in account for the possibility of thunder with heavy downpours moving into southwestern NH between 06z and 08z. Severe weather is not expected with this but of the line survives there could be some torrential downpours and frequent lightning. 610 PM Update...Have updated the forecast, mainly for PoPs based on latest trends in observational data. A couple of storms may occasionally hug the NH/MA border for another hour or two but forcing for ascent will remain rather weak across the rest of the forecast area this evening so have lowered PoPs. The only caveat is the last few runs of the HRRR which bring a convective line into SW NH around 06-07z. This is an outlier at this time, with the convection across western PA having a long way to go to get here. Will monitor trends regardless. Previously... A frontal boundary is currently draped near the NH/MA border with lowering dewpoints and ample cloud cover to the north of the boundary covering much of the forecast area. This boundary is providing a focus for thunderstorms that are currently developing near Albany, New York and similar to yesterday strong to severe storms are expected to develop through this evening primarily south of the NH/MA border into southern New England. Latest RAP analysis does bring 500 to 1000 J/kg of MLCAPE into extreme southern New Hampshire along with about 35 knots of effective shear. Given the latest radar and satellite trends the window for strong to severe storms is closing across southern New Hampshire but cannot rule out a couple strong storms here through sunset this evening. Further north instability drops off quickly limiting the chances for thunder north of a line from KEEN to KPSM with isolated scattered showers over the southern third of the area through this evening. Convection will wane after sunset with the stalled frontal boundary sinking south over southern New England tonight. Cooler and drier air will work into the area overnight from the north allowing for lows to drop into the ow 50s north to low 60s south. Renewed chances for rain will increase across south New Hampshire during the pre-dawn hours as an mid level trough approaches from the west acting upon the frontal boundary. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... Frontal boundary will be stalled across southern New England Thursday morning with waves of low pressure tracking along the boundary. Aloft, a trough at 500 mb will be moving through the Great Lakes with attendant surface low tracking through the St Lawrence Valley through Thursday night. This low will lift the stalled boundary northward as a warm front while drawing in deep tropical moisture from Elsa with PWATs approaching 1.75 to 2 inches by Thursday evening. Expect Thursday to start off relatively cool and cloudy with chances for rain to increase from west to east into Thursday afternoon. Highs will generally be in the 60s with some low 70s across southern New Hampshire. As mentioned in previous discussions the ingredients remain for a predecessor moderate to heavy rain event Thursday afternoon into Friday morning. Now that we are deeper into the window of mesoscale models there is an emerging consensus that the heaviest rain will be focused our west and north across the Adirondacks into southeast Quebec as the 500 mb trough tries to go negative tilt. Current QPF forecast for Thursday through Thursday night, before the arrival of Elsa, ranges for around a half inch near the coast to 1.5 inches in the mountains. However, there is still some room for this axis of heaviest rain to shift and for more details regarding dynamics, rainfall rates, and hydrologic concerns please see the Hydrology section below. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... All eyes shift towards the tropical storm Elsa as we head into the early portions of the extended forecast. 12Z operational and ensemble solutions suggest a continued westward shift in the track of Elsa as it move up the southern New England coastline Friday morning with the 12Z Euro remaining at the western portion of the track envelop. Bands of heavy showers will enter the region during the day. High precipitable water values as well as a strong and dynamic jet aloft may lead to very high rainfall rates Friday and Friday evening as the system tracks along or near the coast of New Hampshire and Maine. Precipitable water values are expected to exceed 2 inches over southern areas for a period on Friday. This early season tropical system may allow for flash flooding to occur over portions of the region. The highest threat locations will be dependent on the exact track of the system. Heavy showers will continue into the early evening hours as the system exits into eastern Maine and the Canadian Maritimes. Plenty of low level moisture in its wake may allow for patchy fog to develop. Gusty winds will accompany the system. The Euro ensemble mean continues to show the highest wind gusts along the Midcoast region of Maine. Winds may gust over 35 mph in this region, however this is highly dependent on the storm track. A lingering trough to our west may allow for a few scattered showers for the remainder of the night, however rainfall intensity should be diminishing during the period. Relatively dry conditions will enter the region over the weekend as a weak ridge of high pressure builds in from Canada. Thereafter, a slow moving trough will approach the region during the early to midweek period, allowing for scattered showers to start out the week. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... Short Term...Mainly VFR tonight with relatively high cigs, although cigs may lower to MVFR at KLEB and KHIE in the pre-dawn hours as rain develops from west to east. VFR with transitions to MVFR and then to IFR/LIFR through the day Wednesday as rain continues to spread west to east with IFR/LIFR likely persisting into Friday morning. Long Term...LIFR conditions in low clouds and heavy rainfall on Friday as Elsa crosses the region. There could be a few rumbles of thunder. Gusty winds are possible, mainly along the Midcoast region such as KRKD. Fog will develop during the evening hours. Conditions will improve by Saturday morning to VFR. A few showers are possible at times on Saturday, but otherwise primarily VFR conditions are expected Saturday through early next week. && .MARINE... Short Term...Winds and seas will remain below SCA thresholds through Thursday night. Easterly winds will increase Thursday, but will generally stay at or below 20 kts Thursday afternoon as low pressure tracks through the St Lawrence Valley and Elsa approaches form the south. Long Term...Tropical Storm Elsa is expected to pass through the Gulf of Maine Friday afternoon and evening, possibly bringing strong gusty winds to the waters Friday afternoon and evening. Seas will build as the storm approaches. Both the height of the seas and strength of the winds will depend on the exact track of the storm, which remains uncertain at this time. A broad trough will cross the waters on Saturday, with ridging building in on Sunday through early next week. && .HYDROLOGY... The potential for localized flash flooding is possible late Thursday into Friday, especially on Friday as moisture from TC Elsa advects into the region. The river flood threat is low as ongoing drought conditions have lowered streamflows and area watersheds have large storage capacity. All large scale models show mid/upper level trough deepening to our west and our mid level flow shifting from zonal to SW on Thursday. Showers will increase in coverage as the deeper moisture arrives over the region. Heating could support higher rainfall rates > 3"/hour in any scattered thunderstorms as PWATs climb to 1.75". By Thursday night the anticyclone curved 250 mb jet of 80-100 kt will be located across southern Canada, placing the right rear quadrant over VT/NH and NW ME. Meanwhile the developing nose of the 850 mb jet around 40 kt will move into NH by early Friday morning. The upper and mid level flows become more southerly Thursday night with PWATs approaching 2.0" (>90th percentile for early July, almost 2 SDs above normal). In our favor is the decreasing thunderstorm cover overnight, however any thunderstorms (even in modest instability) could easily support torrential high rainfall rates (>5"/hr instantaneous rates). Best rain chances during Thursday night into Friday morning will be associated with the coverage on heavy rain on the Midcoast. Other models keep Elsa further offshore pulling portions of the forecast area under subsidence. This would limit rainfall amounts for much of southern and eastern Maine. Event total rainfall will be dependent on convection development on Thursday/Thursday night, and then the ultimate track of Elsa for Friday. Will favor highs amounts in NH/NW ME on Thursday/Thursday night given better dynamics with the upper level jet, and for Friday having the highest QPF along the coast. Will follow HPC and WPC guidance at this stage favoring their Elsa track. Any slight shift in Elsa`s track could increase or decrease rainfall totals. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Ekster/Schroeter SHORT TERM...Schroeter LONG TERM...Cannon
Area Forecast Discussion
National Weather Service Wilmington NC
1126 PM EDT Wed Jul 7 2021 .SYNOPSIS... Tropical Storm Elsa is expected to weaken to a depression as it moves through central South and North Carolina on Thursday. Breezy winds, locally heavy rain, and even isolated tornadoes may occur. Typical summer weather is expected behind Elsa for the weekend with scattered showers and thunderstorms and humid conditions continuing into early next week. && .UPDATE... All Tropical Storm Watches in effect across the coastal ILM CWA have been upgraded to Tropical Storm Warnings. See the various Tropical Statements issued by the ILM and NHC offices. The POPs and cloudiness across the ILM CWA have been updated to account for the flare up of convection on the Southeast Side of Elsa as it lifts northeastward overnight into daylight Thu. Min temps have been upped by 2 to 4 degrees to account for the moisture laden tropical air invading the ILM CWA once the mid- upper s/w ridge axis lifts entirely north of the FA early on during the pre-dawn Thu hrs. QPF overnight has been also upped to account for a slight earlier arrival of the pcpn. && .NEAR TERM /THROUGH THURSDAY NIGHT/... Isolated storms will continue to push inland along what`s left of the enhanced sea breeze this evening and should push north of the area by tonight. The slow storm motion may lead to a few areas of heavy rainfall with a low chance of localized flooding. Rain starts to spread northward this evening with the approach of Tropical Storm (and eventual Tropical Depression) Elsa. Outerbands should start to impact the area tonight and SPC has outlined areas of coastal SC in a Slight Risk for the risk of isolated tornadoes. Per their discussion (and we agree), the outerbands should start lifting northward and there is some uncertainty on how these will interact with the Gulf Stream and the associated instability overnight. The severe threat is likely to continue into Thursday morning with the outerbands moving onshore along the SC and NC coastline. In these areas, we could see the potential for brief tornadic cells, although current parameters suggest any tornadoes would be weak and brief. Elsa`s track continues to push further inland and the latest forecast has it as a Tropical Depression as it pushes just west of the area. We have maintained a Tropical Storm Warning along our SC counties and coastal waters along with a Tropical Storm Watch in our NC coastal areas and coastal waters. The thinking here is that the storm will produce bands of convection over the waters and bring a few isolated wind gusts to tropical storm strength or above. Gusty winds are also possible along the I-95 corridor. Conditions begin to improve late Thursday into Thursday evening as any lingering showers move through the area with little to no additional QPF. Skies clear Thursday night with overnight lows in the lower 70s. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... Elsa should be well north of the area Friday, but a tropical and very humid airmass will linger across the Carolinas. SBCAPE in excess of 2000 J/kg, the seabreeze boundary, and the approach of a weak shortwave during the afternoon should yield scattered showers and t-storms with 40-50 percent coverage. There shouldn`t be a significant severe weather potential with bulk shear around 10 knots, but depending on how much rain falls Thursday with Elsa there could be an isolated lingering flooding potential. Friday`s highs are expected to reach the lower 90s inland with upper 80s on the beaches. Saturday`s forecast remains a bit unclear with large model-to- model variation in moisture depth behind Friday`s shortwave. While I`ll continue with persistence and show a 30-40 percent chance of mainly afternoon showers and t-storms, this may need to be trended downward if the 12z NAM`s idea of precipitable water plunging below 1.5 inches gains more widespread model support. Saturday`s high should again reach the lower 90s inland with upper 80s on the beaches. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... The GFS, ECMWF, and Canadian all agree on the evolution of a retrograding upper ridge off the Mid Atlantic coast early next week. Drier and warmer air aloft within the ridge may reduce the number of showers and t-storms around, especially near the coast on Monday and Tuesday. An upper trough over the southern Great Lakes would normally be expected to move eastward and increase rain chances, but the ridge appears to remain strong enough to prevent any influence from the trough east of the Appalachians. Otherwise the only story next week will be typical mid-July heat with highs in the 90s and heat indices near 100 degrees each day. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... Short/wave ridging will lift north of Southeast NC this evening. This will allow tropical moisture to invade Northeast SC and Southeast NC during the pre-dawn Thu hrs and continuing well into daylight Thu. Expect deteriorating flight rules, with MVFR/IFR conditions likely dominating the terminals during the pre-dawn Thu hrs, 1st the SC terminals then the NC ones by daybreak Thu via latest HRRR model. Have included a 6hr PROB30 group during daylight Thu for all terminals due to the thunder and wind gust to 40+ kt threats as Elsa accelerates northeastward, remaining west of all terminals. Extended Outlook...Residual MVFR/IFR in the wake of Elsa Thursday evening but should improve to just diurnally driven convection Friday through the upcoming weekend and into early next week. With less coverage late in the period due to the expansion of the mid/upper level ridging from off the Atlantic. && .MARINE... Through Thursday Night... With Elsa passing west of the waters during Thursday southerly flow will increase and is expected to be gusty at times especially near any bands of convection that pivot by. Elsa will lift farther away from the waters by Thursday afternoon, which will allow the winds to veer to a southwesterly direction. The fetch will likely lead to seas of 6 to 7 ft by Thursday afternoon. Isolated to widely scattered showers are expected this morning, then a pause in storms this afternoon. The coverage of storms is expected to increase across the waters late tonight, and Thursday in conjunction with Elsa moving across the Carolinas. As Elsa exits the region on Thursday night, winds will gradually decrease along with significant sea height. Friday through Monday... With Elsa moving well north of the area by Friday, the main influences on our winds will become Bermuda High Pressure well offshore and lower pressures across the Mid Atlantic states. Southwesterly winds are expected to continue over the weekend into early next week. Seas should average 4-5 feet Friday in a 5-6 second southerly wind wave. By Monday seas should fall to 3-4 feet, balanced between an 8 second southeast swell and 4 second wind chop. A typical summertime pattern for showers and thunderstorms is expected to develop with most marine storm activity expected to develop at night, shifting inland during the days. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...Tropical Storm Warning for SCZ054-056. High Rip Current Risk through Thursday evening for SCZ054-056. Beach Hazards Statement from 6 AM EDT Thursday through Thursday evening for SCZ054-056. NC...Tropical Storm Warning for NCZ105>110. High Rip Current Risk through Thursday evening for NCZ106-108- 110. Beach Hazards Statement from 6 AM EDT Thursday through Thursday evening for NCZ106-108. MARINE...Tropical Storm Warning for AMZ250-252-254-256. && $$ SYNOPSIS...TRA UPDATE...DCH NEAR TERM...21 SHORT TERM...TRA LONG TERM...TRA AVIATION...DCH MARINE...TRA/21
Area Forecast Discussion
National Weather Service Jackson MS
952 PM CDT Wed Jul 7 2021 .UPDATE... Updated for evening discussion. && .DISCUSSION... Scattered showers and thunderstorms have come to an end over much of the forecast area this evening. A warm and humid night expected again tonight, with partly to mostly cloudy skies. Have made some very minor adjustments to temperatures on the east side of I-55 corridor to account for more cloud cover. Other than that, forecast is on track overall and no major updates are anticipated at this time. Prior discussion below: Tonight and Thursday: Scattered showers and storms will likely continue into tonight, with coverage diminishing after late evening. Lows tonight drop into the lower 70s F with some upper 60s F to near 70 F minimums likely over eastern MS along and north of the I-20 corridor. A broad trough axis, responsible in part for sending Elsa well east of us, will help keep rain chances a bit higher than seasonal with most places seeing showers and storms at some point this evening through Thursday. With the trough being in a slightly less favorable/more easterly position Thursday, rain chances may be slightly lower than we saw Wednesday with upper heights slightly rising. This should result in a warmer day, with much of the area reaching near or just above 90 F. /86/ Thursday night through Tuesday: Thursday wl still have a moist airmass in place with lower 70F dew points and a PWAT around two inches. Our CWA will also be in the weak spot between a 591dam ridge from the west and a 591dam ridge across the northeast Gulf. The convection of the day should see a distinct diurnal trend and dissipate early in the evening. Friday a 1020mb surface ridge will be along the Gulf coast. This will help maintain our low level moisture and daytime heating will set off another round of scattered to numerous storms. Saturday the mid level ridge from the west will become more dominant over our region and result in less coverage of convection. Sunday models remain in good agreement that the mid level ridge to our west will weaken while a northern stream shortwave trough dives over the Plains. This shortwave trough is expected to close off a low over the mid Mississippi valley and help drive a cold front into our western zones by evening. Rain chances will increase Sunday ahead of the cold front. A few strong storms along with heavy rainfall will be likely in our western zones Sunday afternoon and evening. Monday the closed low will be lifting northeast toward the Great Lakes region while upper level troughing lingers over our CWA. The cold front looks to stall across the CWA and become the focus for convection Monday into Tuesday. Morning lows will be near normal through the period but afternoon highs will be held cooler than normal over through much of the period. /22/ && .AVIATION... 00Z TAF discussion: Problematic forecast with widespread convection at the end of day reinforcing llvl moisture and potential for low cigs/vis restrictions. HRRR a little spotty with the IFR conditions through the overnight, and may end up oscillating early on before deteriorating after 04Z. Persistence supports an MVFR/IFR overnight. Back to scattered showers tomorrow afternoon with a little less coverage expected per the latest model runs. && .PRELIMINARY POINT TEMPS/POPS... Jackson 72 90 73 86 / 25 58 21 56 Meridian 69 88 70 87 / 42 65 23 61 Vicksburg 72 90 73 87 / 25 50 21 50 Hattiesburg 72 89 73 85 / 33 52 22 65 Natchez 71 88 71 83 / 27 49 23 58 Greenville 72 91 71 88 / 23 44 18 37 Greenwood 71 91 71 90 / 24 53 21 44 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ HJS
Area Forecast Discussion
National Weather Service Marquette MI
733 PM EDT Wed Jul 7 2021 .SHORT TERM...(This evening through Thursday) Issued at 418 PM EDT WED JUL 7 2021 WV imagery and RAP analysis indicated a broad mid/upper level trough into the western Great Lakes. A trailing shortwave trough approaching Upper Michigan and Lake Superior and 700-300 qvector conv supported some lingering isold/sct -shra over the east half of Upper Michigan. However, the main frontal boundary, baroclinic zone and associated fgen remained well to the south. Otherwise, Vis satellite loop showed clouds over most of the rest of the area except the Keweenaw. Tonight, expect the rest of the showers to only gradually diminish as the mid level trough amplifies but the moisture and stronger forcing slides to the east. Clearing over the northwest half and favorable radiational cooling overnight will allow temps to drop off into the lower 40s over the inland west half while clouds maintain temps in the lower south and east. Thursday, decreasing clouds over the east half will result in mostly sunny skies across west and central Upper Michigan. 850 mb temps in the 8C to 10C range will support highs from the mid 60s north to the lower 70s south. .LONG TERM...(Thursday night through Wednesday) Issued at 209 PM EDT WED JUL 7 2021 The long term period starts off cool and tranquil with a warming trend this weekend into next week. Diurnal shower/thunderstorm chances increase early next week as temperatures warm above seasonal normals. Synoptic scale precipitation chances increase by the middle to end of next week, but the heaviest precipitation may stay to our south. A prolonged period of above normal temperatures appears likely for mid-July with cooler air masses staying well to our north/northwest. Northwesterly flow aloft will be in place at 00Z Friday as a shortwave trough tracks east away from the area. A cool and very dry air mass will be in place across the CWA as a fairly weak 1016 mb surface ridge builds over the area. This cool and dry air mass lingers over the CWA within east/northeasterly low level flow through this weekend. A diurnal shower or two is possible near Lake Michigan on Sunday afternoon, but most of the area will have a gorgeous weekend with abundant sunshine, max temperatures around 80F, and low humidity. Forecaster confidence decreases on Monday as a pair of disturbances approach the area. A weak surface low in the mid-MS valley begins lifting north/northeast on Monday as a low-amplitude trough tracks across the Canadian Prairies. The track of this surface low will be dictated by the strength of the Canadian trough and a blocking ridge along the East Coast. If the surface low tracks near our CWA then some light stratiform rain will be possible across the east. Even if this wave misses our area southwesterly low level flow ahead of the Canadian trough advects a warmer and more moist air mass into the area. Increasing moisture results in diurnal precipitation chances on Monday/Tuesday with perhaps more widespread precipitation on Wednesday/Thursday. Otherwise, above normal temperatures are expected next week. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 733 PM EDT WED JUL 7 2021 VFR conditions will continue thru this fcst period at KIWD/KCMX/KSAW. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 418 PM EDT WED JUL 7 2021 Winds to around 15-20 knots over the west end and south will gradually diminish as high pressure moves in the gradient weakens. Light winds, generally blo 15 knots, are expected through the weekend. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...EK AVIATION...Rolfson MARINE...JLB