Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/22/22

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
630 PM CDT Thu Jul 21 2022 .UPDATE... Issued at 616 PM CDT Thu Jul 21 2022 Updated aviation discussion below. Pops and sky cover have been increased across the northeastern CWA. Two large storms across south central ND should continue moving southeast over the next few hours, potentially impacting the northeast CWA. Still a good amount of CIN in this CWA so the storm should diminish some along their southeast track. && .SHORT TERM...(This Evening through Friday Night) Issued at 250 PM CDT Thu Jul 21 2022 Shortwave activity continues to move through the upper level west to northwest flow. There has been a line of showers moving southeast through North Dakota this afternoon that follows that shortwave trajectory into northeast SD. Some models have some intensification/amplification of the shortwaves across far northeast SD and west central MN this evening. Similar to last night, shear remains high, but CAPE, on the RAP and HREF, at least, is marginal...around 1000 J/kg or less. SPC has a marginal risk this evening for areas south of Pierre. While there is a weak low that is expected to move east across far southern SD this evening, most models show the best forcing remaining south of this forecast area. That said, there will be a weak 25 kt llj that develops ahead of the low after 3z, so can`t completely rule out some thunderstorm development with the jet. Above normal highs are forecast again on Friday as heights rise slightly with a minor amplification/shift of the upper ridge. A low pressure system will move off the Rockies and into SD Friday night. This system may set off some scattered showers and thunderstorms, especially across the north and east. .LONG TERM...(Saturday through Thursday) Issued at 250 PM CDT Thu Jul 21 2022 The long term forecast features lower, near normal temperatures and periodic precipitation chances, as the upper-level flow pattern shifts into predominantly northwest flow. Beginning at 12z Saturday, a ~1004mb sfc and NE/SW-oriented cold front will be positioned across the middle of South Dakota. Aloft, a potent shortwave trough will be digging east-southeast through the region. Models have slowed this system down a bit, which will allow for warmer daytime high temperatures Saturday, especially across south central and northeastern SD and west central MN. Still, the anomalously hot air aloft peaks Saturday morning, with 10 to 15C 700mb temps at 12z (per NAEFS and ECMWF ensemble means), and then quickly cool post-frontal through the afternoon and evening. Good forcing and support aloft will lead to showers and thunderstorms across the eastern CWA Saturday morning (30-60% chance), and activity may linger into the early afternoon ~along and east of the Prairie Coteau as well. Models range quite a bit on how much instability will be present Saturday morning along/ahead of the front, with MUCAPE values generally between 1000-2000 J/kg due to potentially steep mid-level lapse rates and dewpoints in the mid 60s. This, coupled with strong deep-layer shear near/behind the front, will provide a window of opportunity for storms to organize and approach or exceed severe limits. Post-frontal, northerly winds will become breezy with gusts around 30 mph, or stronger across central SD Saturday AM and afternoon. While mostly dry Sunday under high pressure (a weak disturbance may bring showers/storms across south central SD Sunday night), another notable shortwave and associated sfc low and cold front will track through the region from northwest to southeast on Tuesday. Shear and instability may be sufficient for the potential for strong storms with this system as well, though confidence is low at this time. This system will bring a reinforcing shot of cooler air too. The WPC Cluster Page shows all available ensemble members in good agreement about the overall northwest flow pattern across the Northern Plains continuing through the rest of the week, though the ECMWF tries to build in a higher-amplitude upper-ridge across the western US than the GEFS. This suggests that a return to above normal temperatures is on the table during this time. && .AVIATION...(For the 00Z TAFS through 00Z Friday Evening) Issued at 616 PM CDT Thu Jul 21 2022 Terminals KABR,KATY,KPIR,KMBG Prevailing VFR conditions can be expected through the valid TAF period. Thunderstorms over south-central ND should continue moving southeast over the next few hours, potentially impacting the terminals of KABR and KATY. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...SD SHORT TERM...Wise LONG TERM...Lueck AVIATION...SD
Area Forecast Discussion
National Weather Service Columbia SC
848 PM EDT Thu Jul 21 2022 .SYNOPSIS... Scattered storms are again expected on Friday afternoon and evening, with some strong storms possible. By the weekend and into the middle of next week, a typical summer pattern with seasonable temperatures and mainly diurnal showers and thunderstorms are expected each afternoon and evening. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Isolated showers and storms in the southern half of the forecast area early this evening will continue to weaken into tonight. Water vapor imagery indicates some drier air aloft pushing into the forecast area. General upper troughing remains over the area and while recent CAMs runs indicate most of the area will remain dry overnight, around daybreak some showers will be possible along a surface trough in the southeastern portion of the forecast area. Temperatures remain in the low to mid 70s overnight. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... Fairly normal summertime pattern expected to continue across Midlands of South Carolina and CSRA of eastern Georgia. Weak troughing will still be in place across the region on Friday, while height rises towards Saturday will help to weaken the persistent troughing that has been in place for a few days. At the surface, a weak front/boundary will still be in place stretching from eastern NC through northern SC and into Georgia. Along and south of this will be plentiful moisture, with PWs around 2" or greater in the central and southern portions of the area on Friday afternoon. With good heating and surface dewpoints, this should yield good instability values, with the general consensus of 1000-2000 j/kg of CAPE forecast to develop by Friday afternoon. It looks like a weak 700 hPa shortwave is forecast to pass along and north of the surface front, which should help to spark at least scattered showers and thunderstorms during the afternoon and evening hours. Some isolated strong storms are possible, but not expecting widespread strong to severe storms at this time. Additionally, we have seen convection across the region the past two mornings, and I can`t rule that out again given the pattern persistence. Latest HREF does hold on to convection across the region tomorrow morning ahead of the weak surface boundary, so added low-chance PoPs to the grids to account for that. Highs Friday will likely be in the upper 80s across the region, but may get into the 90s if we clear clouds out quickly enough. Rinse and repeat on Saturday, as the boundary only slowly moves out of the region. This should yield another chance at showers and storms, with a few being strong. I think overall chances will be a bit lower on Saturday, with the best chances across the south where the boundary may end up. Highs will again be in the low 90s, with lows in the low 70s both nights. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Seasonal is the word for the long term period, as typical summer weather is expected through next week. Ridging will increasingly build across the region, but underneath that will be a weak inverted trough at 500 hPa and 700 hPa on Sunday afternoon and Monday. PWs will be near normal for this time of year, but less than they have been. Guidance shows values around 1.5"-1.8", which should be enough to yield some showers and isolated storms on Sunday/Monday, but overall coverage looks a bit limited. This actually begins a period of normal to slightly below normal PWs in the models through the end of the period. Even still, ensembles and operational models are in good agreement on the further development of mid-level ridging (500 hPa heights rising to ~594 dm by middle of next week) and a bermuda high to our east. This will lead to seasonal chances of isolated to scattered showers and storms each afternoon, with highs in the low- mid 90s, and overnight lows in the 70s. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... Little convection this evening across the area outside of a couple of showers approaching DNL/AGS. Expectation is that these showers will dissipate before reaching the terminals, although will amend as needed. Otherwise, generally expecting VFR conditions into the overnight hours with scattered mid and high level clouds with diminishing wind below 5 knots overnight. HRRR is again hinting at possible stratus development during the predawn hours through midday arriving from the southwest with some support from the MET guidance while other sources keep VFR conditions. Decided to include a tempo for MVFR cigs after 10z-11z and include prevailing MVFR cigs after 15z with abundant low level moisture in place. Winds will pick up from the southwest around 5 to 8 knots. Scattered convection expected again but confidence not high enough to include mention of storms in the forecast at this time. EXTENDED AVIATION OUTLOOK...Some possibility of patchy late night/early morning fog/stratus late Friday night/early Saturday morning. Less diurnal thunderstorm coverage expected Sat/Sun. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Cleveland OH
1024 PM EDT Thu Jul 21 2022 .SYNOPSIS... A weakening cold front will move across the area from west to east late tonight and Friday morning. After brief high pressure Friday afternoon through early Saturday, a warm front lifts across the area on Saturday. A cold front sinks out of the Great Lakes and moves across the local area Sunday night or Monday, before stalling across the Ohio Valley early next week. && .NEAR TERM /THROUGH FRIDAY NIGHT/... 10:00 PM Update... Raised PoPs to likely in NW Ohio and also moved up the onset of showers and thunderstorms due to the small MCS moving ESE across southern lower Michigan. This feature has produced some damaging winds and localized hail in SW Michigan and is being driven by a mid-level vort max and 30-35 knot low-level jet. Downstream instability is waning in northern Ohio with MUCAPE now falling into the 500-1000 J/Kg range per latest RAP analysis, so expect a weakening trend as this complex enters NW Ohio. But with its forward speed and radar/satellite presence, feel confident that most of NW Ohio will see rain and thunder after 03Z. Gusty winds and heavy downpours will accompany the strongest cores. For the rest of the night, adjusted the PoP forecast to bring showers across the rest of northern Ohio and NW PA about an hour or two faster than the previous forecast, but amounts and coverage will be less compared to NW Ohio. 6:30 PM Update... The forecast remains on track through tonight with no changes made. The weak surface trough has exited SE across PA taking the isolated showers with it. This will leave mostly sunny skies and very warm, although slightly less humid, conditions for the rest of the evening as drier air and some subsidence advect in. The next feature to watch is a weak mid-level shortwave and associated vort max currently crossing Lake Michigan. An 80+ knot upper jet and MUCAPE of 1000-2000 J/Kg are generating a few thunderstorms beneath this feature, so scattered showers/storms should cross northern Ohio tonight as the shortwave continues to progress rapidly through the WNW flow aloft. Current mesoanalysis indicates MUCAPE of 1000 J/Kg across northern Ohio, and this is expected to decrease after sunset, but lift from the entrance region of the aforementioned jet and vort max should still support a few showers and rumbles of thunder. CAMs differ on coverage, but timing consensus moves the majority of this activity through NW and north central Ohio in the 06-09Z timeframe and NE Ohio and NW PA in the 08-12Z timeframe, so kept PoPs as is. It`s possible that an isolated shower could reach NW Ohio as early as 02Z, but most of the activity will be in the aforementioned windows. Original Discussion... A warm, tranquil and somewhat breezy late afternoon and early evening. Enough low-level moisture present near and east of the I-71 corridor for a decent cumulus field this afternoon, and it`s possible there`s a brief sprinkle somewhere from Trumbull to Stark Counties points southeast before 6 PM, but didn`t put in mentionable POPs. Dew points gradually falling through the 60s today with temperatures ranging from the mid 80s to near 90 at the moment. A low amplitude shortwave will zip out of the upper Midwest and through the southern Great Lakes tonight into early Friday. It`s a small, quick-moving system in an otherwise ridgy/dry regime, and generally moves through our area at the diurnal minimum. However, it brings with it a brief shot of large scale ascent beneath the right-entrance quadrant of a small upper-level jet streak, with low-mid level warm/moist advection, a well-defined low-mid level trough axis, and 1000-1500 J/KG of elevated CAPE moving west-east across our area overnight tonight into early Friday. With decent agreement among today`s guidance that isolated to scattered showers/thunder will quickly move across the area with this shortwave late tonight into early Friday, generally raised POPs a bit across the board and hit everyone with 20-50% chances briefly, with chances ramping up into Northwest OH nearing midnight and then exiting our area early Friday. Highest POPs over Lake Erie, northeast OH and into PA, gradually dropping off to the south/southwest. Not expecting any severe or flooding threat late tonight or early Friday, but don`t be surprised if there are some stray rumbles of thunder that wake some people up early in the morning. Lows tonight range from the mid 60s to around 70, warmest in northwest OH and in the urban centers. Lingered some low POPs from into early Friday from northwest PA into east-central Ohio until the trailing surface trough clears, but am expecting dry conditions on Friday after this exits by around midday. If surface convergence lingers longer that may be enough to keep a stray shower or rumble around with some surface-based instability developing with daytime heating, but it would be quite isolated and am not confident so continued with a dry forecast after we clear everything out in the morning. Another warm one for Friday, ranging from the mid 80s in PA to the mid-upper 80s for most of northern Ohio, but into the lower 90s for Toledo. Largely quiet for Friday night with high pressure in control and a dry/stable environment, but can`t rule out the remnants ridge riding convection over the Upper Midwest bringing shower chances to northwest Ohio towards dawn Saturday. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Generally a quiet start to the short term period on Saturday, though the weather will become more active by Sunday. Lingering showers and/or isolated thunder chances may be possible associated with a decaying MCS Saturday morning and early afternoon, though not anticipating anything too significant. Behind this activity, warm air advection will really begin to increase across the region, with substantial capping in place to prevent any additional showers and/or thunderstorms. Above average temperatures in the upper 80s to lower 90s are expected with muggy conditions. On Sunday, an upper trough axis will move east across the Great Lakes, extending a cold front south across the Lower Great Lakes. Latest model guidance is suggesting modest, westerly mid-level flow of around 35 to 40 knots by Sunday afternoon and evening just ahead of the front, resulting in the potential for scattered to perhaps widespread showers and thunderstorms. The severe threat, especially for damaging winds, has increased slightly with this update, given model increases in shear and CAPE, but will be dependent on how unstable the area is able to get, given anticipated cloud cover. Nonetheless, the heavy rain threat remains apparent across the region Sunday evening and overnight, given an anomalously-moist airmass, characterized by PWATs around 2.0 inches, and projected west to southwest storm motions nearly paralleling the front axis. && .LONG TERM /MONDAY THROUGH THURSDAY/... Latest guidance is suggesting that the aforementioned cold front on Sunday evening and overnight will stall just south of the US-30 corridor by Monday and thus we could see additional shower and/or thunderstorm develop along or south of the US-30 corridor in the afternoon and evening hours. On Tuesday, the front will sag slightly further towards the south as weak high pressure builds south across the Great Lakes. Initial thinking is that much of the area will remain fairly dry, though can`t rule out a stray shower and/or thunderstorm in the afternoon and evening. Temperatures will generally be near average in the low to mid 80s on both Monday and Tuesday. By Wednesday into Thursday, the stalled front will begin to lift back north as a warm front, ahead of the next upper trough sweeping east across the Great Lakes region. Average to above average temperatures in the low to mid 80s are expected in addition to a muggy air mass. Still some timing differences on the upper trough and associated cold front, though could see shower and thunderstorm development on both the afternoon and evening hours of Wednesday and Thursday. && .AVIATION /00Z Friday THROUGH Tuesday/... VFR will persist through the TAF cycle, but the one fly in the ointment is a weak cold front crossing the region late tonight which will bring 3 to 5 thousand foot cigs to northern parts of the region closer to Lake Erie and a few showers and possible rumbles of thunder. The best chance to see precipitation is at CLE, YNG, and ERI, but it is also possible at TOL and CAK, just less of a chance so not included in the TAF. Any shower or thundershower would be brief and could lead to brief MVFR before returning to VFR. Dry conditions will quickly return everywhere Friday morning. W to WNW winds will diminish to 5-10 knots this evening and also back to SW tonight ahead of the front before veering W to WNW again Friday morning into the afternoon and slightly increasing to 7-12 knots. Outlook...Non-VFR possible again with isolated to scattered showers and thunderstorms on Saturday and Sunday. && .MARINE... Have allowed most of the Small Craft Advisory to expire, though will hang on to the far east portion of Lake Erie through 8 PM, given westerly winds of around 15 knots. Otherwise, not anticipating any marine headlines through Monday, given flow will be generally south to southwesterly, 10 to 20 knots. Slightly enhanced southwesterly flow of 15 to 20 knots will arrive across the lake on Sunday ahead of a cold front. Winds will shift towards the west, then northwest Sunday night into Monday, but winds will decrease into the 5 to 10 knot range. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...Sullivan NEAR TERM...Garuckas/Sullivan SHORT TERM...Kahn LONG TERM...Kahn AVIATION...Garuckas MARINE...Kahn
Area Forecast Discussion
National Weather Service Des Moines IA
634 PM CDT Thu Jul 21 2022 ...Updated for the 00z Aviation Discussion... .DISCUSSION.../Tonight through Thursday/ Issued at 309 PM CDT Thu Jul 21 2022 Key Messages: -Heat Coming Back, More Intense Friday and Saturday -Thunderstorms Late Tonight and Early Friday -Thunderstorms Saturday, and Multiple Rounds Next Week Discussion: Iowa remains downstream of the H5 ridge axis, keeping middle and upper-level flow northwesterly. There are two areas of surface high pressure, one has moved over the Ohio River Valley, the other is currently pushing southeast out of the Northern Plains. Between the two was some weak convergence that generated a few cumulus clouds in central Iowa this morning with very light rain. There is a weak cold front moving ahead of the surface high pressure system across Iowa. Temperatures are only dropping a few degrees behind it. The main notable difference is the shift to northwesterly winds. However, with the clear skies allowing for insolation during the afternoon, temperatures have still be on rise this afternoon. The overnight southwesterly winds help set the stage for this as well. For the rest of this evening, expect clear skies to continue. A few cumulus clouds may pop up along the cold front, but current GOES-16 visible imagery does not show much in the way of development. There is a subtle short-wave over the Front Range that this evening is expected to start lee cyclogenesis. This will set the stage for a weekend with hot, and potentially wet, weather. Convection is expected to initiate later this afternoon over the High Plains and Central Plains of Nebraska along with this short-wave. This convection will move eastward during the evening and overnight hours as the vorticity maxima ejects eastward. The first question, is if this convection will hold together and congeal into a mature MCS as a LLJ develops across the Missouri River Valley and areas eastward. The deterministic GFS has continued to depict this kind of solution, and keeps the system moving across the entire forecast area. However, members of the GEFS have mixed signals. Several members are showing the initial convection dissipating over eastern Nebraska, but new development occurs in western Iowa with the approach of the short-wave. There will be enhanced Q-vector convergence with this feature, that may provide enough forcing. 12z CAM guidance appears to be in more favor for a redevelopment scenario, rather than having a massive MCS develop. Both of these scenarios leave western Iowa with the best chance for rain showers. Most of this activity will start after 06z tonight. Therefore, the highest POPs are concentrated along and west of Hwy. 71. If the LLJ remains strong enough past 09z, convection may continue going into the mid-morning hours of Friday, and make it to around the Interstate 35 corridor. The general trend in CAM guidance this morning is to dissipate the remnants after 12z as it moves east of Interstate 35. The deterministic GFS is the only solution that keeps higher QPF going later into the early afternoon. As for the severe threat, the low-level inversion will limit any near surface-based parcels. Convection will be rooted above 850 mb being forced by the low-level jet. RAP soundings though are showing steep lapse rates from just below 700mb to around 500mb. Lapse rates are around 8.0 C/km, and effective shear for elevated storms may be around 35 kts. This may support a threat for quarter size hail. A damaging wind gust would not be out of the question, but heavy precipitation loading would likely be needed to punch through the stable boundary layer. If the convection lasts for an extended period of time, most of it should be done after 18z Friday. During the afternoon, the short-wave will pass through, but the surface feature will likely be left behind. Another short-wave develops that may phase and help deepen the surface cyclone. As a result, stronger southwest flow develops ahead of the system, and will provide strong theta-e advection into Iowa. This will will send temperatures back into the 90s across central and southwestern portions of the forecast area. This may not reach the eastern and northeastern portions of the forecast area by the afternoon, which will keep temperatures slightly cooler. Saturday, the second short-wave quickly ejects across the Central Plains. An elongated surface low develops with this, with two local pressure minima. Ahead of this, the warm front surges northward. Yesterday, there was a decent amount of spread with respect to how far north the warm front traveled before stalling. This morning, there is better agreement that the warm front will surge to around Interstate 90 in southern Minnesota. This will put most of our counties in the warm sector of this system. This boundary will eventually stall in the afternoon, with a surface high pressure being forced southward out of Canada due to a strong closed-low system over Hudson Bay. Consensus among individual ensemble members is also higher in this northward placement of the warm front. The shower and thunderstorm potential though is not overly straightforward. While GEFS and other ensemble suites have over 80 percent probability for for accumulating precipitation within 24 hours across most of the forecast area, how many rounds of convection that occurs is not consistent. With the warm front surging overnight, theta-e advection will start early in the morning on Saturday. This push of moisture may allow for stronger isnetropic ascent, and elevated convection may develop on Saturday morning. Therefore in the forecast, have placed widespread slight chances for areas that will enter the warm sector during the morning. If elevated convection does develop, most of this should dissipate by the afternoon. The wind shear does not look overly impressive for any elevated stuff Saturday morning. However, Saturday later in the afternoon this changes. As the H5 short-wave approaches, deep layer shear will be on the rise, and close to the boundary 0-6km values around 50 kts. The ambient warm sector may see 30-40kts about 50 miles south of the boundary. As the high drops south of out Canada, the stalled boundary will also be forced south, and will serve as a cold front across the region. Yesterday, the capping looked very strong across the ambient warm sector, and even in close vicinity to the boundary. Today, guidance has decreased the MLCIN some. while increasing the strength of the convergence. Therefore, the threat for thunderstorms and potential for severe thunderstorms has increased for Saturday evening. This is highlighted by the SWO Day 3 Slight Risk. An Enhanced Risk exists northeast of the forecast area. Most of the severe risk is focused along the boundary, as this is also where surface pressure falls will be strongest throughout the afternoon. While a cap is a potential source of limitation, the bigger one may actually be lingering convection and cloud debris from morning elevated convection. The GFS is hinting at decreased instability in the ambient warm sector, with MLCAPE values only around 1000 J/kg. There is still a ribbon of MLCAPE over 3000 J/kg directly along the boundary. Perhaps if theta-e advection is strong, there may be enough to overcome the lack of insolation should clouds stick around. If deep convection is hindered in the afternoon, the push of the front across the area should be enough for widespread showers late Saturday and continuing overnight into Sunday Morning. Severe threat in this scenario would be low. Aside from the severe convection, heat indices may also become a concern. The strong push of WAA will send temperatures at least into the lower 90s. If the warm sector clears during the afternoon, air temps in the upper 90s are possible in central and southern Iowa. This would send heat indices to near 105. However, morning convection may hinder this. Because of the convection potential, have held off for issuing any heat related headlines today for Saturday. However, be prepared for excessive heat on Saturday afternoon. Extended: Although the flow will be zonal several times, a number of PV anomalies will send multiple vort maximums across the upper Midwest for this upcoming week. At this time, it is hard to pinpoint exact timing of precipitation. Somewhere in Iowa will have a slight chance of rain showers each day Sunday through Wednesday. The severe threat will be better determined at a later time. Temperatures will be average to just slightly warmer. Periods of showers may provide relief from the heat. && .AVIATION.../For the 00Z TAFS through 00Z Friday evening/ Issued at 624 PM CDT Thu Jul 21 2022 VFR expected through the TAF period with locally MVFR possible from thunderstorms. There remains uncertainty regarding the longevity of thunderstorms so left VCTS for short duration in western terminals for early Friday. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION...Krull AVIATION...REV/Jimenez
Area Forecast Discussion
National Weather Service Quad Cities IA IL
616 PM CDT Thu Jul 21 2022 ...AVIATION UPDATE... .UPDATE... Issued at 453 PM CDT Thu Jul 21 2022 While convection along the primary surface cold front continues to struggle, we`ve developed a few shallow convective showers over locations in far eastern Iowa, well west of the cold front. This is where dewpoints have not yet dropped from the 70s, and we`re getting to use some of this CAPE present, though the fast movement and small updrafts are unlikely to result in more than a brief heavy showers. I`ve updated pops for these showers and weak t-storms through 7 PM. ERVIN && .SYNOPSIS... Issued at 300 PM CDT Thu Jul 21 2022 Shortwave is traversing northeast IA, southern WI with a vort max moving into far northwest IL at 2 PM. Day cloud phase satellite depicts more robust cumulus and isolated convection developing far northwest IL into southern WI. A much more subtle shortwave denoted by some mid cloudiness was traversing our southern cwa. At the surface, a cold front extends from near a Dubuque to Fairfield line. Temps across the area at 2 PM were in the upper 80s to lower 90s, with heat index readings in the mid/upper 90s in areas ahead of the front. && .SHORT TERM...(Through Friday) ISSUED AT 300 PM CDT Thu Jul 21 2022 Key Messages: 1) Isolated shower/storm possible northeast late this afternoon. 2) More comfortable humidity tonight. 3) Chance for showers and storms Friday. Discussion Will have the potential to develop isolated/widely scattered convection over the next couple of hours, mainly over our NW Illinois counties, within zone of PVA amidst a moderately unstable and uncapped atmosphere. Water vapor imagery does show a lot of dry air and so this entrainment may lead to some struggle with updrafts, hence any coverage remaining rather sparse. If a storm gets going, can`t rule out some gusty winds with advection of steeper mid level lapse rates, inverted V soundings, and DCAPE 1300+ j/kg. Better potential in terms of convection and any isolated severe threat could remain more north/east of cwa. Further south, a very subtle mid level impulse will continue slide through our far southern counties. This region looks to remain capped and in absence of stronger lift likely will remain dry. After the front moves through, northwest winds will begin to usher in drier dew points (mid 50s to lower 60s upstream into northern and central IA as evidence). This should result in a more comfortable night with lows in the 60s. Satellite and HRRR smoke model indicate potential for some thin haze/smoke layer moving in this evening south/west, but nowhere as thick as what we observed last evening. Late tonight, another wave approaches in west/northwest flow and is likely to spawn some convection in one or more clusters upstream of our area. This activity is likely to slide southeast and weaken but move across portions of the cwa Friday AM with a veering weak nocturnal LLJ and attendant elevated warm air advection. Have kept PoPs in the lower chance category for now due to the anticipated weakening nature, but this will need to be monitored. Some redevelopment may occur Friday PM, particularly north of I-80, in the elevated warm advection ahead of a surface warm front. Confidence remains low on severe weather due to potential AM precip and debris clouds, but if some organization can occur with any storms, then strong wind gusts would be possible. Highs tomorrow likely to range from the mid/upper 80s north to the lower 90s. Heat index readings could reach into the upper 90s to near 100 across far southeast Iowa and northeast Missouri. .LONG TERM...(Friday Night through Thursday) ISSUED AT 300 PM CDT Thu Jul 21 2022 Key Messages: 1. Potential for heat indices on Saturday to be over 100. 2. Several rounds of showers and storms Friday night through Thursday. 3. There is a marginal or level 1 risk for severe storms Friday night. There is a slight or level 2 risk for areas north of Interstate 80 on Saturday afternoon and evening with a marginal risk to the south. Discussion: Models vary through the long term period on the key details of the forecast but there is good agreement in the large scale pattern. The overall 500 mb synoptic pattern through the period will continue ridging over the southwestern US and low pressure across southern Canada placing the area under an active northwest flow aloft. This will allow several shortwave to move across parts of the area through the period. An MCS is forecast to develop Friday night to our northwest with the development of the low level jet and potentially veer into our area overnight. Models disagree on where this feature will track across the Upper Midwest with some models bringing it into our area. Due to this potential, there is a marginal or level 1 risk for severe storms Friday night across the entire area with the potential for hail and damaging winds. Models show increasing precipitable water values overnight in the 1.0 to 1.25 inch rain so there is the potential for heavy rain. Depending on where the MCS tracks Friday night will impact the forecast for Saturday as any morning clouds and storms would impact the temperature forecast. Currently, there is the potential for some clouds to overspread the northern half of the area during the morning into the afternoon. Models show strong warm air and moisture advection through the day with air temperatures warming into the 90s from north to south across the area. Dewpoints will increase into the lower to mid 70s producing heat indices across the area of 100 to 105. This is solidly in heat advisory criteria and a headline may need to be issued in later forecasts to account for the hot and humid conditions across the area on Saturday. These warm temperatures and increasing humidity will provide ample fuel for thunderstorm development ahead of a shortwave trough dropping southeastward across the western edge of the trough. Currently, this shortwave will arrive during peak heating with storm development expected to our northwest. Models show very high CAPE values in the 3000 to 4000 J/KG along with deep layer shear of 30 to 40 knots. Currently storms to our northwest our forecast to congeal into a southeastward propagating line and move across eastern Iowa, northwest Illinois, and far northeast Missouri. The may threats will be hail and damaging winds as well as heavy rainfall with precipitable water values increasing to around 1.75 inches by Saturday night. For these reasons, the storm prediction center has placed a slight or level 2 risk for severe thunderstorms along and north of Interstate 80 with the remainder of the area in a marginal or level 1 risk. Behind this system, the very warm and humid air will be pushed slightly to our south for Sunday through the remainder of the period. The current forecast has high temperatures in the lower to mid 80s through the remainder of the period with low temperatures in the 60s. However, the pattern will remain active with daily chances of showers and storms as shortwave pass across the area each day. There will be dry periods but they are hard to pin down resulting in broad brushed chances through the period. && .AVIATION...(For the 00Z TAFS through 00Z Friday Evening) ISSUED AT 612 PM CDT Thu Jul 21 2022 An isolated shower is possible in northwest Illinois through 7 PM. A period of VFR weather with light northwest winds will be most of tonight, but towards morning, the front that moved by today, will return as a warm front, possibly with a cluster of storms passing through in the 12Z to 16Z window. This remains low confidence, and will retain the Prob30 thunder forecast. Otherwise, a return to VFR south winds will be expected by Noon Friday. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...Ervin SYNOPSIS...McClure SHORT TERM...McClure LONG TERM...Cousins AVIATION...Ervin
Area Forecast Discussion
National Weather Service Grand Rapids MI
1137 PM EDT Thu Jul 21 2022 LATEST UPDATE... Update .UPDATE... Issued at 1135 PM EDT Thu Jul 21 2022 Our convective event is just about cleared Southwest Michigan. The storms causing some power outages in parts of Kent, Allegan, Kalamazoo, Calhoun and Jackson Counties, likely caused by the gusty winds, locally heavy rain, some small hail. Behind the storm skies are clearing and should stay clear overnight. That is due to some ridging both surface and aloft as the shortwave that caused the convection this evening moves out. There is enough winds in the boundary layer to keep any widespread fog from developing. Friday will see the surface ridge axis pass through our area ahead of the next system. Most of the day should be warm and dry. The RAP and HRRR suggest dew points could fall into the 40s by mid afternoon Friday while air temperatures rise into the mid to upper 80s. That results in RH values below 30 percent and given winds will be gusting to 20 mph in the afternoon, that would increase the danger for wild fires. && .DISCUSSION...(This evening through next Thursday) Issued at 257 PM EDT Thu Jul 21 2022 ...Risk for a few thunderstorms this evening... A 850/700 mb trough dropping southeastward through WI is forecast to track through the CWA this evening. Surface based instability values of around 1000 to 1500 J/kg exist out ahead of this feature...especially toward Holland and Kalamazoo. Forecast soundings show an inverted V look to them and DCAPE is over 1000 J/kg. These two parameters/features support strong wind gusts with any stronger cell. Forecast low level convergence favors the area generally south of a Muskegon to Grand Rapids line for the most shower/storm activity. This is where we will feature the highest POPs. ...Additional showers and thunderstorms possible late Friday night... The latest runs of the models appear to focus the main storm activity just southwest of the CWA late Friday night. The low level jet and stronger instability is shown to be aimed in those locations. Still...some deep moisture and weak instability is shown for southwest parts of the CWA which will allow for at least scattered showers and thunderstorms. Close monitoring will be needed going forward as a northward shift of the low level jet and instability could lead to an increase in the storm coverage for the CWA. ...Numerous showers and storms look likely for Saturday night into early Sunday... An unseasonably strong mid to upper level wave will be tracking eastward through the Canadian Prairies and into Ontario. On the south side of this feature...the mid to upper level flow strengthens over the Great Lakes Region. At the same time a strong southwesterly low level jet will be moving into the Great Lakes Region and advecting in abundant moisture. Deep layer shear will be quite strong through the night. As a result of all or more MCS`s look possible in this window with an increased risk for severe weather. In addition with PWAT values forecast to climb up over 1.75 inches locally heavy rain is likely. If the storms repeat over the same area...some flooding may occur. The low level jet and instability gradient shift south and east of the CWA by 18z Sunday so much less in the way of storm coverage is forecast by then. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 749 PM EDT Thu Jul 21 2022 There will be thunderstorms at most of our TAF sites this evening. Due to the dry sub-cloud layer gusty winds are likely with these storms so I put at TEMPO group in the TAF with wind gusts near 30 knots to allow for that. Expect brief IFR visibilities with these storms as they do have intense rain cores. Some hail should be expected with the stronger storms as well as the typical shifting wind field and frequent lighting. The storms should be out of this area by 10 pm or so. The rest of the night should feature skies clearing and winds light from the west or west southwest, mostly under 10 knots. Friday should see VFR conditions all day but another shortwave may bring clouds in late in the day. Winds may become gusty by afternoon as a result of the shortwave moving closer to the area. Any storm would be after 00z but I expect most of those should be south of our TAF sites (we will watch that through). && .MARINE... Issued at 257 PM EDT Thu Jul 21 2022 The pressure gradient tightens up across the northern zones later Friday into Friday night as a wave of low pressure tracks eastward through the northern Great Lakes Region. Southwesterly winds will increase...especially for Little and Big Sable Points by Friday evening. Hazardous conditions for small craft and swimmers may develop. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ UPDATE...WDM DISCUSSION...MJS AVIATION...WDM MARINE...MJS
Area Forecast Discussion
National Weather Service Northern Indiana
748 PM EDT Thu Jul 21 2022 .SYNOPSIS... Issued at 254 PM EDT Thu Jul 21 2022 Warm but less humid conditions will be in store on Friday. Heat and humidity will build for the weekend with peak afternoon heat indices in the mid to upper 90s expected on Saturday. Slight chance of showers and thunderstorms are possible this evening. Periodic chances of showers and storms will follow for Friday night through the beginning of next week. && .UPDATE... Issued at 747 PM EDT Thu Jul 21 2022 Continuing to monitor convection from west of KGRR SW to over S Lk MI back to north of the Chicago metro area. A few of the storms have attempted to organize with one in particular over mid lake (and now dropping ESE towards South Haven) exhibiting transient supercell characteristics, semi deviant in its overall motion at times (E then SE then back to E) and likely produced severe level winds over the lake. Exactly how these storms will continue to unfold is still uncertain, but HRRR still seems closest to reality with current setup so tending to lean somewhat towards it. If it is to be believed, convection should continue to drop SE and may expand somewhat as it runs into at least 1000 to maybe 2000 J/KG of CAPE still in place after dark. While severe threat still likely minimal will monitor trends. As for pops, at this point will clean up a bit to adjust timing, but keeping in slgt chc to chc for now to see if everything holds together or even expands some. && .SHORT TERM...(This Evening through Friday) Issued at 254 PM EDT Thu Jul 21 2022 Breezy conditions today will continue over the next several hours ahead of a short wave originating from the northwest. The breezy conditions continues to create moderate swim risk on Lake Michigan beaches, earlier reports from Warren Dunes and Silver Beach indicated 3 foot waves. This shortwave is moving through a northwest flow aloft and will increase chances for some showers and even a few thunderstorms later this evening. The best chances look to be the more northern portions of our CWA however a few storms cannot be ruled out further south. Any of the storms that develop are not expected to become severe. Main threats would be gusty winds and brief heavy rainfall, and of course dangerous cloud to ground lightning. This shortwave will continue to move east to southeastward through the area by late tonight. Winds will trend lower with the exit of the disturbance. Precipitation amounts will be minimal with the showers, locally heavier amounts would be expected with any thunderstorms however. && .LONG TERM...(Friday Night through Thursday) Issued at 254 PM EDT Thu Jul 21 2022 Temperatures will trend higher over the next couple of days with a westerly to northwesterly flow in place and synoptic heights slightly increasing on the northern periphery of an elongated ridge over the mid south. The hottest day will be on Saturday with highs ranging in the upper 80s to low 90s. Surface moisture will also increase on Saturday with dew points in the upper 60s to lower 70s. This will make Saturday a bit uncomfortable with heat indicies in the mid to upper 90s. Several more disturbances will move through the quasi-zonal flow aloft over the next several days bringing periods of increased chances for showers and thunderstorms. Saturday will have decent surface moisture along with ample surface warming. A disturbance moving through will provide enough instability and lift to bring a decent chance of thunderstorms. Shear may be the limiting factor. Will have to keep an eye on that. SPC currently has our entire area under a marginal risk for severe storms on Saturday. A Hudson Bay trough will push lower heights southward beginning Sunday bringing relief in the form of a cooling trend. Sunday high temperatures will be slightly cooler than Saturday with highs in the mid 80s and low 90s. But on Monday and Tuesday high temperatures will be noticeably cooler with highs in the upper 70s to lower 80s. Precipitation chances look to remain increased with the zonal flow firmly in place continuing to bring western Canadian disturbances through the region. && .AVIATION...(For the 00Z TAFS through 00Z Friday Evening) Issued at 747 PM EDT Thu Jul 21 2022 Focus of TAFs (mainly at KSBN) remains on non-zero threat for isolated convection over the next couple of hours. Been tracking widely sct showers/storms which now extend from south of KMKG to over S LK MI to N of KORD. These will continue to track ESE with a few cells in far SE WI to over the SW part of the lake possibly taking aim on KSBN. Despite how the radar looks, confidence quite low on will it impact the site and if so how strong will it be. Enough signals to introduce a VCSH mention with maintenance of VFR conditions for now. Given the isolated nature any impacts would encompass a very narrow wind which will diminish the later we go. If coverage/intensity expands will amend accordingly. Have left KFWA dry as even lower confidence anything makes it to the site and it it does most likely will be a high based shower. Once this threat has passed, VFR conditions to dominate with a shift to NW winds behind the front. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ UPDATE...Fisher SYNOPSIS...Andersen SHORT TERM...Andersen LONG TERM...Andersen AVIATION...Fisher Visit us at Follow us on Facebook...Twitter...and YouTube at:
Area Forecast Discussion
National Weather Service Lake Charles LA
845 PM CDT Thu Jul 21 2022 .UPDATE... Heat advisory expired at 7 PM this evening as temperatures and heat index values decreased across SE TX. Current temperatures are running a little cooler than expected thanks to increased clouds across the region as well as a few cooling showers earlier today. Despite this, overnight lows are still on track to reach the middle and upper 70s. KLCH radar shows convection has diminished considerably, with just a couple of small isolated showers remaining in the CWA. Expect generally quiet conditions overnight. Convection occurring near the AR/LA border a few hours ago has also decreased, with the more intense activity now propagating toward central MS. Some models suggest that some of this convection, while becoming weaker, could hold together as it moves southward then southwestward toward central LA late tonight. However, 00Z HRRR guidance is downplaying this scenario (waiting on 00Z HiRes as of this writing). At this time, no changes to the forecast are anticipated, other than adjusting hourly temperature and dewpoint grids to reflect obs/trends. 24 && .PREV DISCUSSION... /issued 524 PM CDT Thu Jul 21 2022/ DISCUSSION... For the 07/22/2022 0000 UTC TAF package. AVIATION... Radar showing scattered TSRA over Acadiana region, will keep the VCTS through 01z when they are expected to diminish. Elsewhere, TSRA likely over for the day, thus took out VCTS for AEX, BPT, LFT. Otherwise, South to southwest winds will diminish after sunset, and pick up to near 8-10 kts after 15z Friday. Slightly higher SHRA/TSRA chances over Acadiana region, thus will introduce VCTS for ARA/LFT by 18z. With the higher chances of SHRA/TSRA Friday, VCTS introduced by 15z. 08/DML PREV DISCUSSION... /issued 353 PM CDT Thu Jul 21 2022/ SHORT TERM [Tonight through Saturday]... A bit of an impulse made its way around the upper level ridge and produced cloud cover and shower activity across the northern zones earlier today. This activity has pretty much dissipated, however the left over cloud cover and the late start on max daytime heating has kept heat index readings in check over that area. Scattered showers and thunderstorms are now developing further south with the sea breeze and this activity will continue until sunset and then diminish. Heat Advisory for southeast Texas will also continue until 7 pm local. The lack of convection for those zones along with anomalously high Gulf moisture made for oppressive heat index values between 108 and 112 degrees that will persist in spots away from any cooling showers for another couple of hours. On Friday, the upper level ridge will break down briefly across the forecast area. This will allow a surface boundary to come down to just north of the forecast area from the north, and a mid level inverted trough and moisture surge to move in from the east. The combination of the two should allow for the best chance for showers and thunderstorms this week. Still some question to when the best coverage will be, some hi res guidance showing a MCS feature for the morning, while others should activity waiting to develop until the afternoon. Probably the truth is in between with some activity for the northern zones in the morning and the remainder of the area in the afternoon. The convection and cloud cover on Friday will help keep the heat in check and not seeing any heat index readings near heat advisory criteria. PWAT values on Friday will be in the 2.0 to 2.25 range with mean layer RH from the surface to 50H over 70 percent. So there could be some heavy rainfall with the stronger convection. The area has been dry and could take some rainfall, however, there is a Marginal Risk for Excessive Rainfall on Friday from WPC, mainly if the high rainfall rates fall over urban poor drainage areas some street flooding could occur. On Saturday, the upper level ridge begins to build back to the east and allow for a typical summer time day, with diurnal convection. Rua LONG TERM [Sunday through Thursday]... Upper level ridging will become broadly centered from north Texas across Oklahoma and Arkansas Sunday and Monday. This is expected to keep afternoon convection and cloud cover limited across central Louisiana and interior parts of southeast Texas which will allow afternoon highs to once again flirt with or exceed triple digits. Closer to the coast, scattered, diurnally driven, convection will keep temperatures closer to seasonal normals, but mid 90s will be possible across areas that do not see afternoon storms. An inverted trof will slide from east to west across the northern gulf beginning Tuesday through the middle of the week providing upper level support for more widespread convection especially closer to the coast. The upper ridge north of the region will also begin to push off to the east Wednesday allowing more substantial precip coverage across central Louisiana. This should aid in bringing temperatures back to more seasonal values. Jones MARINE... Typical summertime pattern looks to be in place during the forecast period. A surface high will be centered east of Florida and ridge across the northern Gulf of Mexico and into the coastal waters. This will result in a light to occasionally moderate onshore flow, with mainly low seas. There will be a daily chance of showers and thunderstorms, mainly nearshore in the late morning and afternoon, and offshore late at night into the morning. Rua && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...None. && $$
Area Forecast Discussion
National Weather Service Paducah KY
621 PM CDT Thu Jul 21 2022 .UPDATE... Issued at 620 PM CDT Thu Jul 21 2022 Updated aviation discussion for 00Z TAFs. && .SHORT TERM...(Tonight through Saturday night) Issued at 333 PM CDT Thu Jul 21 2022 Temperatures have underachieved today, but dewpoints have held in the middle 60s over most of the region. The less hot conditions today make the expected warming for Friday a little more extreme, on the order of 10 degrees, which may be a little harder to swallow. The upper ridge is coming back Friday, but the surface ridge will still be cutting north to south right through the middle of the region. This will keep south winds from kicking in much, even in the west, which will hold back the humidity and possibly the temperatures. We stuck close to the NBM for temperatures and went with a mix of the ConsShort and NBM dewpoints. The result yields max afternoon heat indices from 103-106 over most of southeast Missouri and adjacent portions of southern Illinois and west Kentucky. After collaboration with WFO SGF, LSX, and MEG we decided to issue a Heat Advisory for Friday for that area. The HRRR actually develops some widely scattered convection over much of Missouri Friday afternoon and evening, including near our Ozark Foothills region. Given the uncertainty in the temperature and humidity increases in that area, it is hard to believe there will be any tangible convection there. We will keep the forecast dry, but will keep a wary eye on the convective possibilities. The upper ridge will continue to build overhead Saturday and south southwest winds will kick in throughout the area. Confidence is much higher for heat and humidity to return over the entire area, with max afternoon heat indices reaching the 104-111 range. Much of the region will see high temperatures in the upper 90s to lower 100s, with the hottest conditions expected over southeast Missouri. While the humidity will be increasing we are not seeing any evidence that it will as nasty as we experienced yesterday. A Heat Advisory has been issued for the entire area Saturday and with similar conditions forecast for Sunday, we decided to run it through the entire weekend. Low temperatures will trend warmer through the period. Tried to lean a bit to the low side for lows tonight and Friday night, but with south winds and humidity returning Saturday, Saturday night will be quite mild with lows in the mid to upper 70s expected. .LONG TERM...(Sunday through Thursday) Issued at 333 PM CDT Thu Jul 21 2022 The latter half of the weekend will be clear to partly cloudy and sultry under a flat ridge of high pressure aloft, with highs 95 to 103 and heat indices 100 to 110 (110 possible west of the MS River). A heat headline should still be in place for Sun into the early evening. The approach of a surface cold front from the north and its associated shortwave energy aloft will increase the probability of showers and tstms developing progressively farther south in the moist and increasingly unstable airmass Sun night. By Mon, PoPs will increase to 40-50% as the front sinks farther south into the PAH forecast area. The front is expected to stall sometime on Mon and eventually make its way north, but additional ripples in the mid level flow are expected to act on the moist and unstable airmass, keeping healthy PoPs for showers/tstms in the forecast, mostly during the days and evenings. There are some model indications that Wed could offer up a brief reprieve in the scattered activity between shortwaves, but at this time frame, differences exist in the medium range model solutions with timing and evolution of these shortwaves, thus we will keep a 35-45% PoP in for Wed/Wed night. The models suggested, with some timing differences, that a larger mid level shortwave and attendant surface cold front may move into our region on Thu (Day 7) providing a solid chance of showers/tstms. Temps are expected to cool somewhat by Mon with the increased cloud cover and scattered pcpn, with highs in the upper 80s common in southern IL/southwestern IN Mon and Tue, with 90s in southeastern MO and parts of western KY. Wed may possibly provide an uptick in highs, with 90s experienced across the entire region. Heat indices of over 100 are possible. If the forecast holds, Thu could be a bit cooler by a few degrees. && .AVIATION... Issued at 620 PM CDT Thu Jul 21 2022 VFR conditions will persist through Friday. Near calm winds tonight should become predominantly southwest to west at or below 5 knots on Friday. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...Heat Advisory from 11 AM Saturday to 8 PM CDT Sunday for ILZ075>078-081>083-085>087-089>091-094. Heat Advisory from noon Friday to 8 PM CDT Sunday for ILZ080-084- 088-092-093. MO...Heat Advisory from noon Friday to 8 PM CDT Sunday for MOZ076-086- 087-100-107>112-114. IN...Heat Advisory from 11 AM Saturday to 8 PM CDT Sunday for INZ081- 082-085>088. KY...Heat Advisory from 11 AM Saturday to 8 PM CDT Sunday for KYZ001>003-005>022. Heat Advisory from noon Friday to 8 PM CDT Sunday for KYZ004. && $$ UPDATE...RJP SHORT TERM...DRS LONG TERM...DB AVIATION...RJP
Area Forecast Discussion
National Weather Service Pocatello ID
207 PM MDT Thu Jul 21 2022 .SHORT TERM...Tonight and Friday. We continue to watch for the ridge to break down over the next 24 hours. Limited monsoon is still expected to kick off a few thunderstorms across the Albion Mountains and southeast highlands through midnight. We aren`t expecting much other than some sprinkles and gusty winds if something can sustain itself long enough to produce even that. While the potential is almost zero, it is still NOT zero across portions of the central mountains on the northern end of the moisture push. There will at least be some continued cloud buildups. We should see any potential for showers and storms ending overnight. For tomorrow, the low offshore weakens and lifts across the Panhandle. The biggest risk we will see comes from gusty winds and drier air. At the moment, we aren`t seeing enough wind for any type of Lake Wind or Wind Advisory headlines. There should still be enough monsoon moisture for isolated storms along the Montana border and also across the Albion Mountains and southeast highlands. We might see a few storms across the southeast corner produce some light rain and gusty winds. Temperatures will be similar vs today across most of eastern Idaho, although it looks like western locations will be just a couple of degrees cooler. Keyes .LONG TERM...Saturday through Thursday. Saturday looks a bit cooler with any gusty winds confined to the Arco Desert and also the ridgetops of the central mountains. We MAY see a storm or two across the eastern and southeast highlands, but chances are really, REALLY low. Another weak storm crosses the state, with an uptick in wind and also the potential for isolated storms across the southeast corner. Beyond that, we actually will be under northwest flow as high pressure rebuilds to our west. We may see a few storms from time to time around Island Park or along the Wyoming border as storms clip eastern Idaho. Temperatures will only be slightly warmer next vs what we will see over the weekend. Keyes && .AVIATION...For the 18Z TAFS through 18Z Friday. Upper level ridge overhead and will gradually begin to fill in as a FEW/SCT deck across the South Hills and Southeast Highlands this afternoon expanding to the Central Mountains and Eastern Highlands by this afternoon. Convective clouds building in this afternoon will lead to a SCT/BKN deck over the mountainous terrain with showers and thunderstorms along the Utah border region just like yesterday south of the Snake Plain, staying south of KPIH and KBYI. Winds will remain less than 15 kts for all terminals with clear skies returning after sunset. The breakdown of this upper level ridge feature falls tomorrow with stronger afternoon winds being the primary concern. The latest HRRR smoke guidance shows continued smoke impacts aloft from the Moose Fire burning locally in the Salmon-Challis NF, reducing visibility at the surface and especially aloft at times throughout the day. If flying through the Lemhi Range to Salmon visibilities could be reduced to less than 4 miles. Stronger S/SW winds tomorrow will allow for improvements in smoke coverage as smoke remains confined to Lemhi County and along the Montana border north and east. MacKay/Preston && .FIRE WEATHER...We are still expecting a classic ridge breakdown pattern tomorrow across central and eastern Idaho. Ahead of that, we are still looking for isolated dry storms this evening closer to the Utah border in 427 and 413. Little rainfall and gusty winds are possible. We are watching afternoon clouds across the central mountains for any development, but so far nothing is happening. Expect poor overnight humidity recovery across most of our mountain fire zones...except for portions of 411 and 413 near the Wyoming border. Values below 25% are forecast closer to ridgetop across the central mountains and a good chunk of 411, 413 and 427. For tomorrow, with the breakdown of the ridge...we will see stronger winds developing. With humidity values already low and potentially even a bit lower across most areas, we will see widespread critical fire conditions over the central mountains and across zones 425 and 410. We have converted the FIRE WEATHER WATCH to a RED FLAG WARNING from 10am-9pm tomorrow. We will see pockets of critical conditions across the rest of the area. We considered a warning for Zone 427 and 413 but conditions should be isolated enough to preclude that...for now. We will also be watching for some isolated showers and storms tomorrow, mainly along the Utah border in 427 and 413. The potential for wetting rains in those areas is around 15% at best. We could also see a few storms along the Montana border, but the most likely scenario is for storms to remain in Montana. Saturday will be a bit cooler. We will see some gusty winds across 410 and ridgetops. At the moment, gusts will remain low enough to keep things out of Red Flag territory. While chances are at best 10%, a storm could pop up along the Wyoming border and around Bear Lake. A weak low crosses the state Sunday. At the moment, the main risks may again come from the combination of gusty winds and low humidity. Right now, it looks like we stay BELOW threshold for Red Flag Warnings but we will be looking closer at over the weekend. A few storms may fire again closer to the Wyoming border with what monsoon moisture is around. Heading into next week, it looks mostly dry but we will be under northwest flow as high pressure reloads to our south and west. We may see an occasional shot of thunderstorms around Island Park and the Wyoming border. Keyes && .PIH WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from 10 AM to 9 PM MDT Friday for IDZ410-425- 475-476. && $$
Area Forecast Discussion
National Weather Service Tallahassee FL
838 PM EDT Thu Jul 21 2022 .UPDATE... Raised pops this evening and overnight along our western CWA boundary as convection to the north has organized and is moving southward. Questions remain on how strong it will be when it reaches us and how much of this convection actually moves into our area. Latest HRRR has much of the precipitation staying to our west but enough probabilities remain to atleast bump rain chances up a little. No other changes were needed for the tonight. && .PREV DISCUSSION [739 PM EDT]... .NEAR TERM [Through Friday]... The widespread wet pattern that`s been in place across the region is expected to continue at least one more day into Friday as a weak upper level trough lingers over the area. For the rest of this evening, much of the convective activity is expected to reside across our Alabama and Georgia counties where a weak boundary was noted around 3pm this afternoon. As noted by the most recent WPC MPD (mesoscale precipitation discussion), moist southerly flow south of this boundary and weak northerly upper level flow aloft should at least lead to very slow progression of this boundary north through the afternoon. This could lead do a localized threat for flash flooding across our AL/GA counties through the remainder of the afternoon and evening. Additionally, the weak upper level trough helping to aid this convection will slowly drift southeast through the evening as it becomes increasingly elongated. This means convection across the area this evening could linger into the overnight hours, especially if stronger convection upstream of the area across northern AL/GA remains organized into the evening hours as it moves south. However, this largely depends on how the boundary progresses through the overnight hours. By Friday morning, storm coverage should gradually decrease but with the weak boundary still residing to our north, we can`t rule out isolated/scattered storms across our Alabama and Georgia counties in the morning hours around sunrise. With southerly flow expected to remain in place at the surface tomorrow, the best rain chances will again be across AL/GA. With weakening upper level flow, expect the potential for localized flooding again on Friday with a moist airmass in place fueling high rain rates. .SHORT TERM [Friday Night Through Saturday Night]... A boundary across the region Friday night will weaken, however, with it lingering around the area, it will help to keep some convective activity persisting across the region into Friday night. Upper level ridging begins to build into the tri-state area on Saturday and this combined with slightly lower PW values (1.6-1.9 with pockets of 2") will help to keep PoPs a little lower then what we`ve seen lately, more in the 30-50% range. Some activity will continue into Saturday night as a shortwave rounds the upper level ridge. As the ridge builds into the region on Saturday, highs will tick upward a few degrees into the lower 90s with lows in the mid 70s. .LONG TERM [Sunday Through Thursday]... High pressure will continue to build into the region on Sunday with a few perturbations in the flow. PW values will trend upward to 2+ inches and this will lead to more convection across the region on Sunday compared to Saturday. High pressure will elongate west to east north of the CWA next week and bring the deep layer flow more to the east or southeast. The chance for showers and thunderstorms will remain in the forecast each day. Expect highs in the lower to mid 90s with lows in the mid 70s. .AVIATION... [Through 00Z Saturday] Watching a developing area of convection in central Alabama progged to move south with time this evening. Hi res guidance, of varying degrees, does show movement into our CWA later this evening. This area could be severe on arrival, or at the very least, strong winds could accompany the storms at DHN or as far east as ABY. Have tempos for convection later this evening. Through the day Friday, convection will develop along the outflow and perhaps back into southeast Alabama in the afternoon hours. .MARINE... Favorable boating conditions are forecast the next few days outside of thunderstorms. Tranquil seas of less than 2 feet are expected this weekend as initially southwest winds become light and variable under the influence of surface high pressure. Southeast winds at around 10 knots arrive late in the period. .FIRE WEATHER... Fire weather concerns should remain low for the next few days, mostly in part due to the wet pattern we`ve observed lately. Drier conditions with less chance for rain is expected over the weekend along with warmer temperatures. With high pressure expected over the weekend, dispersions will be on the lower side. .HYDROLOGY... Wet weather continues through Friday and as such, a Marginal Risk (level 1 of 4) for excessive rainfall is in place over southeast AL, bordering FL Panhandle counties, and southwest GA tomorrow. Reduced rain chances are forecast this weekend thanks to a more typical summertime pattern returning. Only localized flooding is a concern from strong, efficient-rainmaking thunderstorms. Urban, low-lying, and poor-drainage areas are most susceptible. The latest 7-day QPF amounts are generally 1.5 inches or less. In terms of rivers, Ochlockonee - Havana (US-27) is in action stage, but cresting and expected to fall below by Saturday night. .SPOTTER INFORMATION STATEMENT... Spotter activation is not requested. However, spotters are always encouraged to safely report significant weather conditions when they occur (while following all local, state, and CDC guidelines) by calling the office or tweeting us @NWSTallahassee. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 74 92 73 94 74 / 10 50 10 40 10 Panama City 78 88 77 89 77 / 40 40 10 40 10 Dothan 74 87 72 90 73 / 40 60 20 40 10 Albany 75 90 73 92 74 / 20 60 30 40 20 Valdosta 73 93 73 94 73 / 10 50 20 50 20 Cross City 74 93 74 94 73 / 10 30 20 50 20 Apalachicola 78 88 76 89 77 / 20 20 10 30 10 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...High Rip Current Risk until 2 AM EDT /1 AM CDT/ Friday for Coastal Bay-Coastal Gulf-South Walton. GA...None. AL...None. GM...None. && $$ UPDATE...Scholl NEAR TERM...Dobbs SHORT TERM...Fieux LONG TERM...Fieux AVIATION...Scholl MARINE...Fieux FIRE WEATHER...Dobbs HYDROLOGY...IG3