Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/23/22

Area Forecast Discussion
National Weather Service La Crosse WI
651 PM CDT Fri Jul 22 2022 .DISCUSSION...(Tonight through Friday) Issued at 200 PM CDT Fri Jul 22 2022 Key Messages: - A few storms possible in the south tonight - Significant severe weather event possible Saturday - More rain chances Tuesday night/Wednesday - Cooler temps for next week * TONIGHT: a few storms possible, mostly south Water vapor satellite imagery shows shortwave pulse in western Minnesota with attendant frontal boundary draped into northwest Iowa and eastern Nebraska. The warm sector theta e lobe containing mid 60F surface dewpoints continues advecting southeast this afternoon, nearly zonally draped over our warning area tonight. Convection today will be limited by a 850 mb capping warm nose (~25C), indicated in the 12Z RAOBs (DVN/MPX). High res ensembles hint at scattered possibilities, with little consensus. Therefore, have not added PoPs, but will monitor for pop up diurnally driven convection similar to yesterday. The nocturnal low level jet ramps up to 30-40 kts tonight advecting near 2" precipitable water values into the zonally-CWA-bisecting boundary. High resolution ensemble paintball plots place increased reflectivities along the nose of the low level jet, with SREF mean soundings indicating elevated convection. HREF mean MUCAPE near 2000 J/kg grazes our southern periphery with warm cloud depth reaching 13,000 ft. Sufficient speed shear within the hail growth zone will keep hail as a threat, as well as heavy rain and strong winds. Storms expected to be progressive at this time, limiting heavy rain threat. Have increased PoPs along our southern periphery. * SATURDAY: Severe Weather Threat Severe threat increases for Saturday afternoon as multi level synoptic forcing collocates through the Northern Plains. An excited upper level jet streak containing multiple waves collocated with positive mid level vorticity advection and increased low level moisture transport within another increased theta e lobe places severe weather threat across all of our forecast area. Surface dewpoints within this positive theta e lobe will eek into the mid 70s, on another nearly zonal axis near Interstate 90. Have increased surface dewpoint temperatures slightly above National Blend to align closer to 50th percentile among model guidance. With this increase, max heat indices flirt with triple digits in our southern counties. However, with limited temporal window (~1hr), will not issue headlines at this time. An initial surface boundary will advect southeast out of central Minnesota during the afternoon with convection expected to pop up along this line. Timing will be dependent upon upstream development and progression of storms out of the Dakotas in the morning associated with synoptic forcing. HRRR model guidance suggest discrete cells initiating into western Wisconsin ahead of this SE MN line hinged on a warm boundary/ meso triple point, morphing with the upstream line as it passes through the forecast area into central Wisconsin. All types of severe weather are possible with ample shear values at all levels, including a mesoscale convective system. Primary threats continue to be strong winds, large hail, and locally heavy rain. CSU GEFS-based machine learning probabilities for tornado/wind/hail encircle the entire forecast area, and have increased for both strong winds and tornado potential compared to yesterday. Given the inverted V high resolution model soundings, microburst winds will be a concern. Clockwise turning hodographs in the 0-4km layer contain ample SRH, however with higher LFCs and well mixed model soundings, difficulty becoming surface based leaves tornadoes as secondary threat. However, along aforementioned dewpoint/CAPE surface boundary spin up possibilities could be increased. The upper level trough sags through the area into the overnight hours, bringing a final round of precipitation. Forecast busters/dependencies that should be mentioned: A slight low level cap for select SREF members and deterministic models does NOT appear to be an overall limiting factor at this time given more than ample instability. Convection firing off the Dakota border Saturday morning will be more of a factor. While model guidance suggests ideal collocation of synoptic parameters in our area, an outrunning cold pool or dislocation of synoptic forcing will change behavior of convection. * TUE NIGHT/WED: another shot for rain GFS and EC in fairly good agreement with driving an upper level shortwave trough/sfc cold front across the upper mississippi river valley Tue night/Wed morning. Some differences in timing, but good support from the models` ensembles members. Timing could limit instability (about 1k J/kg of MUCAPE) while deeper layer shear could lie westward, into the cooler air. Some moisture return per 850 mb moisture transport with 4 km warm cloud depths/1.75" PWs to fuel storms (and some locally heavy rain potential). Severe risk looks low at this time, based on model trends for timing. Will run with NBM for rain chances. * NEXT WEEK: trending cooler After the steamy day Saturday, cooler air will start to filter into the region, with another push of cooler air post the weather system Wed morning. EC ensembles have been trending cool for the past several days with 75% of its members at or below normal through Friday. Roughly only 5 degrees or so, so not significant cold (upper 70s/lower 80s for highs). Tue likely the warmer of the upcoming days, ahead of the next rain maker. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 651 PM CDT Fri Jul 22 2022 A scattered to broken 4 to 6K deck of clouds will continue through 23.02z along and just north of Interstate 90. After these clouds dissipate with the loss of diurnal heating, there may be a scattered 10 to 15K deck from storms moving east across northeast Iowa and southwest Wisconsin overnight. On Saturday afternoon, a line or lines of thunderstorms will move southeast across the area. Some of these storms could become severe with damaging winds (up to 60 knots), large hail, and maybe even a few tornadoes. Currently went closer to the NAM Nest timing of storm arrival around 23.19z at KRST and 23.20z at KLSE. However, the confidence in the timing of these storms is not as high earlier. This is due the HRRR being about 2 to 3 hours earlier. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ DISCUSSION...JAR/RIECK AVIATION...Boyne
Area Forecast Discussion
National Weather Service Bismarck ND
1022 PM CDT Fri Jul 22 2022 .UPDATE... Issued at 1014 PM CDT Fri Jul 22 2022 Severe thunderstorms continue to push eastward through McHenry, Pierce, and Rolette counties. The southern storm has been rotating a lot, feeding on the 400 meters squared per second squared. Has not produced a tornado but did get a report of a funnel cloud earlier with a rotating wall cloud. We have maintained the mention of golf ball sized hail because of the strong meso with 70 mph winds in the warning. The severe storms are almost out of our area but some storms behind these in Bottineau County. We are watching these to become severe as well. Early Saturday morning with the low-level jet kicking in, another round of storms is expected across the central and south. Timing for these are around 07z, but the CAMS dont all agree on the timing. We keep updating PoPs to reflect the current radar trends. UPDATE Issued at 640 PM CDT Fri Jul 22 2022 Currently monitoring the International border as a storm as fired along the cold front just north of the border. This storm should slide into our area later tonight, as well as more storms developing. Hand analysis at 21z showed a moisture pool north of Highway 2 between a warm front in the central and the cold front in Canada. This is where we are watching for storm development when this cold front slides south into North Dakota. The shear vector is out of the west, so storms will slide mostly east along the fronts. Cumulus clouds are also along the warm front in central North Dakota, not sure if storms can fire along this being it is already warm there. There is another storm just across the border in South Dakota that is non-severe. Looks like the storm has slip and the left mover is moving into our area, possibly too much shear there for organized severe storms. We will also be monitoring this area close as well. SPC has a 60% chance for a Severe Thunderstorm Watch in the north. We have updated PoPs as the previous forecast had storms moving in sooner than what is actually occurring. && .SHORT TERM...(This evening through Saturday) Issued at 218 PM CDT Fri Jul 22 2022 Main forecast challenges are convective potential, initially over the north this evening and then shifting to southern ND later tonight. Water vapor imagery continues to show shortwave trough over eastern Washington/northern Idaho, pushing eastward across the broad upper level ridge. As this feature approaches the Northern Plains, surface low will strengthen in the vicinity of northwest ND with a strengthening frontal zone also. Latest surface analysis showed surface low over eastern Montana, with pressure falls extending into western ND. Latest SPC mesoanalysis data show 1000-1500 J/kg of MLCAPE and 40kt effective bulk shear centered over northwestern ND. Satellite imagery also shows cumulus spreading into southwest ND with some light radar returns. Added some low pops across our southwest to account for this during the remainder of the afternoon. The area in northern ND will serve as a focus for potential convection by late afternoon/early evening. Several CAMs depict strong/severe convection crossing from Canada into far northwest ND and traveling east/southeastward. HREF updraft helicity probability output also favors this region, which is covered by the marginal area in the SPC Day 1 outlook. HRRR guidance is less aggressive, likely due to stronger capping per forecast soundings over northwest ND. HRRR brings some strong storms into the northeast CWA later this evening, around 02Z. The second area of concern is our south central and southeast CWA late tonight, which is supported by a low level jet intersecting the southward moving frontal zone. RAP guidance indicates around 2000 J/Kg of MUCAPE over far south central and southeast ND coincident with 40-50 kts of 0-6km shear. Pops in the forecast account for these trends, with increasing pops across the north from west to east, with slightly lower pops southwest, in a less favorable environment. By late night, highest pops (up to likely) are in place over the southeast. After any remaining convection departs the region Saturday morning expect decreasing clouds, northerly surface winds and cooler temps with highs from the mid 70s north to low 80s south. .LONG TERM...(Saturday night through Friday) Issued at 218 PM CDT Fri Jul 22 2022 Surface high builds southward across North Dakota Saturday night, with mostly clear skies and light winds. With an upper low over Hudson Bay, flow aloft over our region remains northwesterly initially. By Monday night, an upper level trough approaches from the northwest and exits the region on Tuesday. This brings the next chance of precipitation, followed by mostly dry weather with temps running near to below normal as northwest flow is reestablished. Overall, the pattern looks relatively quiet with neither CIPS Severe Analogs or CSU MLP guidance suggesting any significant severe weather concerns in the extended period. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 1025 PM CDT Fri Jul 22 2022 VFR conditions through the period. There is a chance for strong to severe thunderstorms in the central and south around 07z. Winds will mostly be out of the north, gusting up to 20kts Saturday afternoon. Wind shear is possible at KBIS and KJMS Saturday morning. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Smith SHORT TERM...JNS LONG TERM...JNS AVIATION...Smith
Area Forecast Discussion
National Weather Service Boston/Norton MA
946 PM EDT Fri Jul 22 2022 .SYNOPSIS... Continued hot with moderate levels of humidity this weekend. Heat is oppressive on Saturday and Sunday. Perhaps into Monday, but less certain as a cold front brings showers and thunderstorms. Dry and more seasonable weather, with lower humidity, is expected Tuesday and Wednesday. Another frontal system brings a chance of showers and thunderstorms on Thursday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 945 PM update... Small area of convection across eastern NY to NE PA moving eastward ahead of a mid level shortwave. As this shortwave moves east, there is a low risk a brief shower could spill into SNE, but expect much of this activity to weaken as the boundary layer stabilizes. Stratus and fog along and E of ACK may back in across Cape Cod and Buzzards Bay overnight. Previous discussion... 420 pm update... Monitoring developing convection just off to our west in association with an approaching shortwave. Although surface temperatures are in the upper 80s to some mid 90s, lapse rates are not all that impressive and MLCAPE values are generally less than 500 J/kg. There is also a good amount of dry air per mid-level water vapor, so it is not a very supportive environment for anything more than isolated and not very deep convection. Latest CAMS are basically "meh" with regard to much happening into the evening. Doing some timing of what is currently on radar, we should see isolated showers into the CT River Valley about 5pm, but not expecting them to make their way much further east. So will keep with the generally 20% PoPs in the forecast for far western areas. A couple of the hi-res models, namely the HRRR and RAP indicate that later tonight an area of elevated instability and moisture will traverse across the region and bring the potential for isolated showers. Have added in a 15- 20% PoP for basically northern CT across RI and to SE MA for this possibility. If there is any shower activity, no significant rainfall is expected. Otherwise kept with the guidance blend for overnight lows which will range from the mid-60s across those "colder" higher elevations to around 70F most everywhere...except lower 70s in the urban areas. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... 420 pm update... No big changes to the Saturday forecast. Pretty much sunny and hot with moderate levels of humidity. Zonal flow aloft with a flat ridge and continued southwest low level flow. 925mb temperatures will be a smidge warmer than today, generally in the 23-25C range. That easily supports highs in the 92-95F range at lower elevations. With plenty of sunshine again, and the ground on the dry side due to the lack of rain, hedged toward the warmer guidance and went a little above the 75th percentile from the NBM and have most of the region in the 93- 98F range. Should see another day with decent boundary layer mixing, which will act to keep dewpoints in the more tolerable low 60s range. So although it will be hot, the apparent temperatures (heat index) will be pretty much equal to the air temperature. May again be a sea breeze along the east coastal areas, but if it does happen it probably won`t make much of an inland push of more than a mile or so. General southwest flow will mean the "cooler" temperatures will be along the south coast, Cape and Islands, but they should still top out around 90F in many areas -- just as we saw today. Quiet but very warm weather for Saturday night. Given we should be warmer on Saturday, overnight lows will also be a little higher so most everyone will stay at or above 70F. That means in the center of the bigger cities (Hartford, Providence and Boston), overnight lows will only be in the mid to upper 70s. Therein exists issues for those most at risk to heat related problems. The current Heat Advisory for tomorrow looks spot on, and no changes were made. Do the best you can to stay cool and hydrated with water. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Highlights * Heat Advisories continue through Sunday. Heat peaks on Sunday with some spots flirting with 100 degree temps. A few showers/storms may leak into the interior Sunday afternoon/evening. * Still hot and humid on Monday, but will see the shot for more widespread showers/storms as a cold front moves through into Monday night. Not out of the question there could be a few stronger storms. * Drier and cooler on Tuesday and Wednesday. Another shot for showers/storms on Thursday. Sunday... Remain under cyclonic flow through this period. A shortwave will lift from the central Great Lakes through the eastern Great Lakes during the day into northern New England/Quebec by the evening. Expecting it to be dry and quiet for the vast majority of the region through this period. Continued the trend of increasing temps and lowering dew points as there should be strong mixing within the boundary layer per GFS/NAM Bufkit soundings. Will see a roughly 20- 35 kt SW low level jet lift into the region. At 850 hPa temps will be in the 19-22 degree Celsius range, but do have some concerns that the mid level cloudiness could keep some spots from really maximizing temps. Due to this have gone with the 75th percentile of guidance for highs. The latest and previous EPS guidance indicates low/moderately high probabilities of temps AOA 100 degrees for the CT and Merrimack Valley. This is however not the cause with the GEFS/GEPS guidance. For now with the 75th percentile temps are approaching 100 in these spots, but much of the region away from the south coast should have no problem getting into the 90s. Given the deep mixing anticipated have lowered dew points to the 25th percentile of guidance. For most this brings dew points into the 60s during the peak of the heat, which results in heat indices peaking in the mid to upper 90s for most. There may be a few spots getting into the 100-102 range, so am holding off on an Excessive Heat Watch at this point. Will be something we need to keep a close eye on, but have a catch twenty two here because if temps warm further due to deeper mixing the dew points also would be drier. Regardless if folks are heading outdoors they will want to stay hydrated. Not out of the realm of possibilities an Excessive Heat Watch/Warning is needed in a future update. Think that the risk for low 70 degree dew points is highest along the immediate south coast due to the persistent SW flow, but temps will be a bit cooler. Have generally stuck with the NBM for precipitation chances across southern New England during the afternoon/evening. Think that the risk for some scattered showers/storms is greatest across the interior where activity from NY leaks in. May be more difficult further to the south/east due as it is more removed from the forcing. At this point do not think there is a severe risk as the 30- 40+ kt deep layer shear is more centered over NY/northern New England. Will have roughly a few hundred to 1000 J/kg of MLCAPE with adiabatic low level lapse rates and poor mid level lapse rates. Think that the deep mixing and lower dew points will taper down how widespread the activity is. Will have a better shot on Monday as the front is moving in. Monday into early Tuesday... Still under cyclonic flow through this period. Will have a slightly more amplified shortwave dig from Ontario late on Sunday into Quebec/northern New England by late Monday. This lifts northward late on Monday. At the surface a cold front will slide into and through much of southern New England. This will bring us our next shot for more widespread showers/storms. Stuck with the NBM through much of this period, but tapered back chances especially earlier in the day. Will be well enough removed from the forcing that most other than far NW MA may be dry during the morning. Depending on the amount of cloudiness this could lead to MLCAPE values increasing to 1000-1500 J/kg along with increasing deep layer shear in the 0-6 km layer. By the afternoon should see values in the 30-50 kt range with low level lapse rates of 6-8 degrees Celsius and poor mid level lapse rates. Given the parameter space do not think it is out of the question there could be strong to severe storms. Am a bit skeptical due to the upper forcing being well removed and destabilization is a bit of a question. Will point out that both the CSU Machine Learning and CIPS Severe Analogs highlight a severe risk for our area. Still a bit early to do a deep dive into the specific, but definitely something to keep an eye on. Given the persistent SW flow will have PWATs increasing to 1.75-2.25 inches and warm cloud layer depths of 3.5-4.5 km, so could have some heavy downpours at times. Fortunately most of the region needs the rain and the things look progressive. Not completely out of the question we see another day where Heat Advisories are needed. Given the SW flow will have dew points in the low to mid 70s for most. Much of the region will have temps well into the 80s with some low 90 degree readings in the CT/Merrimack Valley. Right now think risk is highest for the CT/Merrimack Valley where Heat Index Values are in the 95-100 range, but given the cloudiness am not confident enough on the temps to extend the Heat Advisory into Monday. May be needed in future updates. Tuesday through Thursday... Have stuck with the NBM through this period as the emphasis in the extended was placed on the prior periods. Ridge axis builds into the Great Lakes on Tuesday and eastern Great Lakes/New England Wednesday. Next shortwave/trough lifts in heading into Thursday. High pressure builds over the region Tuesday and Wednesday. Frontal system brings the shot for more showers/storms on Thursday. In wake of the cold front will see much more seasonable temps and comfortable humidity levels on Tuesday/Wednesday. Humidity levels climb up on Thursday, but temps remain seasonable with the shot for showers/storms. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Tonight...High confidence. VFR across the vast majority of the region. Cannot completely rule out an isolated shower across CT/RI and perhaps SE MA. Have kept VCSH in at PVD/FMH/HYA, but confidence in coverage of shower activity is lower than average. At the moment HRRR is only piece of guidance showing this. Main concern is the Cape/Islands as stratus and fog spread in. Should lower to IFR/LIFR limits for most with the lowest at ACK. Light WSW/SW winds. Saturday...High confidence. VFR across southern New England. Moderate confidence in sea breeze developing at BOS given it occurred today under similar conditions. Guidance is somewhat conflicted in winds remaining AOA 10 kts below 2 kft. Window appears to be in the 15-19Z timeframe before flow strengthens. Elsewhere WSW winds at 5-10 kts. Saturday night...High confidence. VFR across much of southern New England. Will see low clouds/stratus likely in IFR/LIFR limits spreading into the Cape/Islands due to SW flow. Light SW/S winds. KBOS...High confidence overnight. Moderate confidence on sea breeze between 15-19Z. KBDL...High confidence in TAF. Outlook /Sunday through Wednesday/... Sunday: VFR. Breezy. Slight chance SHRA, isolated TSRA. Sunday Night: VFR. Breezy. Chance SHRA, slight chance TSRA. Monday: Mainly VFR, with local MVFR possible. Windy with local gusts up to 30 kt. SHRA likely, chance TSRA. Monday Night: VFR. Breezy. Chance SHRA, slight chance TSRA. Tuesday through Wednesday: VFR. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. 410 pm update... high confidence in the forecast. Fairly persistent weather pattern with a Bermuda high pressure system off the Atlantic Coast producing southwest flow across the coastal waters. The high will remain in place over the weekend. This large area of high pressure is generating some 8 to 10 second swell from the south that will slowly diminish on Saturday, however the resulting wave heights are reaching marginal Small Craft Advisory thresholds mainly across the more exposed southern waters. Outlook /Sunday through Wednesday/... Sunday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Sunday Night: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Slight chance of rain showers, isolated thunderstorms. Monday: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Rain showers likely, chance of thunderstorms. Monday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Rain showers likely, chance of thunderstorms. Tuesday: Winds less than 25 kt. Local rough seas. Slight chance of rain showers, isolated thunderstorms. Tuesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Wednesday: Winds less than 25 kt. Seas locally approaching 5 ft. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Heat Advisory from 11 AM Saturday to 8 PM EDT Sunday for CTZ002>004. MA...Heat Advisory from 11 AM Saturday to 8 PM EDT Sunday for MAZ005>007-011-013>022. Heat Advisory from 10 AM to 8 PM EDT Sunday for MAZ002>004- 008>010-012-026. Air Quality Alert from 11 AM to 11 PM EDT Saturday for MAZ007- 020>022. RI...Heat Advisory from 11 AM Saturday to 8 PM EDT Sunday for RIZ001>007. Air Quality Alert from 11 AM to 11 PM EDT Saturday for RIZ006- 007. Air Quality Alert until 11 PM EDT this evening for RIZ006>008. MARINE...Small Craft Advisory until 2 AM EDT Saturday for ANZ235-237. Small Craft Advisory until 8 AM EDT Saturday for ANZ254>256. && $$ SYNOPSIS...BL/Nash NEAR TERM...KJC/Nash SHORT TERM...Nash LONG TERM...BL AVIATION...BL/Nash MARINE...BL/Nash
Area Forecast Discussion
National Weather Service Caribou ME
940 PM EDT Fri Jul 22 2022 .SYNOPSIS... Weak high pressure builds into the region through tonight. A cold front approaches from the west on Sunday then slowly crosses the area Sunday night and Monday. High pressure then builds over the region into the middle of next week. && .NEAR TERM /THROUGH SATURDAY NIGHT/... 9:38 PM Update...Stray spotty thunderstorms have been crossing the St. Lawrence Valley west of Western Aroostook County. Added a slight chance of a stray thundershower in far western Aroostook County through mid evening. Otherwise, adjusted temps mostly to lower temps in cooler central valleys through mid evening. A large upper level trof to the north will continue to pull in a weak high pressure surface ridge into the region tonight. Vorticity models indicate a vort max moving across the north through the night, and recent high res QPF models show a SW flow over the waters and W flow on land. This will bring some convective showers across the north and help develop a marine layer offshore. Can’t rule out a possible isolated thunderstorm in the north in the evening due to high CAPE and steep lapse rates, though the RAP has much higher values, while the HRRR is significantly lower. Patchy fog is expected in this area with the moist soil and low winds. For the south, high dewpoints and SW flow with the marine layer, could push fog onshore. In addition, some isolated showers are expected to develop along the coast. Not much change is expected for Saturday morning and early afternoon. 925-850mb temps show a pocket of warm air along Downeast and the Central Highlands. With the low level jet increasing WSW winds, this warm airmass will move north, warming temps into the upper 80s. By the afternoon, high-res models and vorticity models show a shortwave moving into the area, bringing rain showers and instability. The 12Z runs indicate the system is slowing down and not progressing as far south as previously forecasted. Decided to pull showers and thunderstorms out of Downeast, and increase chances in the North Woods. In addition to the showers, the low level jet will increase, bringing breezy SW winds, especially in the north. && .SHORT TERM /SUNDAY THROUGH MONDAY/... An upper level shortwave will move through the area Saturday evening. The timing is a bit late in the day for stronger storms, but isolated to scattered thunderstorms are certainly possible for northern zones. DCAPEs and inverted Vs could be a concern if storms arrive earlier. Shear looks more than sufficient. Did keep thunderstorms in the forecast until midnight. The big story for Sunday will be the heat index with values above 90 for most of the area except the coast. The heat index may also prompt advisories for southern Piscataquis and Penobscot counties. Once again, an upper level shortwave rotating around a vertically stacked low near James Bay will arrive in the evening. Northern zones are most likely to be affected. The late arrival mitigates concerns over strong winds with thunderstorms, but given the strong bulk shear and expected SBCAPE, an earlier arrival could result in severe storms. Instead, the very moist dew points in the mid to upper 60s, PWs increasing towards 2 inches, a strong LLJ and potential for training cells draws attention to the potential for heavy rainfall. At this point, it`s hard to pin down the location more than the potential. Most guidance points towards northern zones in the evening, and then possibly shifting south later in the night. On Monday, the PW max shifts east of the area, but destabilization is expected ahead of a strong cold front. SBCAPE and shear both look robust and maintain mention of thunderstorms through Monday afternoon. Severe storms are a possibility. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... The cold front brings drier air and high pressure Monday night into Wednesday night. Temperatures will become more seasonable. The next frontal system appears most likely to arrive later Thursday and have ramped up PoPs for Thursday night. Drier air returns Friday. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: Mainly VFR for tonight and Saturday morning. For tonight, WSW winds decreasing to light winds before midnight. By Saturday, MVFR/IFR in rain showers and thunderstorms in the afternoon for north terminals. SW winds increase to 5-15 kts with gusts up to 25 kts. SHORT TERM: Saturday night...VFR outside of evening thunderstorms north of GNR and HUL and a chance of fog at coastal locations such as Machias and Eastport. Light winds. Sunday...VFR until late afternoon when thunderstorms are expected north of GNR and HUL. Sunday night and Monday...Chance of thunderstorms. Coastal fog possible for sites from BHB towards Eastport. LLWS possible Sunday night. Monday night into Wednesday...VFR && .MARINE... NEAR TERM: Winds and seas will remain below SCA conditions tonight and Saturday. Visibilities will be low tonight in patchy marine layer fog. SHORT TERM: Fog will remain in the forecast for Sunday into Monday evening. In spite of the stability, winds may approach SCA criteria Sunday night. Wave heights are a better bet to eventually reach the 5 ft SCA criteria Sunday night into Tuesday morning. Expect just one significant wave group from the south with a period in the 7 to 8 second range. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Beach Hazards Statement from 8 AM EDT Saturday through Saturday evening for MEZ029. MARINE...None. && $$ Near Term...Bloomer/LaFlash Short Term...MCW Long Term...MCW Aviation...Bloomer/LaFlash/MCW Marine...Bloomer/LaFlash/MCW
Area Forecast Discussion
National Weather Service State College PA
1043 PM EDT Fri Jul 22 2022 .SYNOPSIS... Hot and humid conditions will prevail through the weekend. Record-challenging high temperatures and oppressive heat index values may occur Sunday afternoon across the lower terrain and valleys of Central and Southern PA. Isolated strong thunderstorms are possible during the afternoon and evening Saturday and Sunday. Looking ahead to next week, the highest probability of rain is in the Sunday night into Monday timeframe and Wednesday into Thursday. && .NEAR TERM /UNTIL 8 AM SATURDAY MORNING/... Skies were clear to partly cloudy across the region this evening. Temps ranged from the comfortable upper 60s across the highest terrain of the north and west to the 70s in many other locations. Readings were still in the 80-85F ranged across the far SE part of the CWA. Expect to see varying amounts of mainly thin cirrus streaming east over some patchy low clouds and light valley fog overnight. Lingering light SW winds will diminish to near calm for the overnight hours and min temps will range from near 60F across the northwest to around 70F in the southeast or between +3F and +10F above normal. && .SHORT TERM /8 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... Rising heights (by about 60 decameters) are progged by model guidance Saturday, leading to a slightly hotter and generally dry day. However, a weak and compact shortwave approaching from the Grt Lks could support a few tstorms in the afternoon and evening, with the highest POPs across the NW Mtns and Laurel highlands per the signal in several model suites, including the HRRR, RAP NAM and GFS. The guidance is split however, with some of it (such as the GFS) carrying a MCS SEWD and only nipping our SW zones. Other hi-res guidance indicates a mid-level trough with a few-svrl Deg C of cooling and better 0-3 km shear on the order of 20-30 kts. Can see SPC extending the DY2 MRGL area a bit further east and over the western 1/3 to 1/2 of our forecast area Sat afternoon and early evening. Max temps will trend ~ +2-5F warmer on Saturday vs. today (Friday): -mid to upper 80s in the northern/western mtns -upper 80s to low 90s in the south central ridge/valley region -low to mid 90s across the middle to lower Susquehanna Valley && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... Increasingly warm and muggy conditions are expected Saturday night and Sunday, when ensemble mean 850mb temps surge to around 20C ahead of an approaching cold front. We expect this to support near record highs from the upper 80s over the Alleghenies to the mid and upper 90s over the Lower Susquehanna Valley. The combination of heat and rising dewpoints is expected to produce heat indices topping 100F over the Lower Susquehanna River Valley. Deep mixing will result in gusty winds (25 to 35mph) mixing down to the surface as well, so Sunday will be hot and blustery. The forecast for Sunday afternoon is an interesting one owing to competing factors. Deep mixing will likely allow lower dewpoints to mix down to the surface, and would generally cause temperatures to rise a bit above expectation. Meanwhile, some guidance indicates there could be some convective cloud debris drifting across Central PA Sunday morning, which would serve to temper temperatures. In summary, this type of set up has the potential to lead to overperforming temperatures, but morning clouds may limit the potential. Meanwhile, dewpoints will probably dip a few degrees below expectation. As a result, maximum heat index values are a bit uncertain at this point along with the placement of potential future Heat Advisories. Sunday night will be the warmest night of the stretch by a good margin. Lows will only drop a little bit below 80 degrees in the Lower Susquehanna Valley with 70s on tap for all but the far northwest. Overnight warmth is often more hazardous than afternoon heat, so take precautions as necessary. A cold front will drift southward across central Pa during the day on Monday. Model trends continue to slow the pace of this system a little bit. The slower pace of this cold front will have two primary effects on Monday`s forecast: (1) warmer high temperatures in the Lower Susquehanna, with potentially a 7th day in a row with Tmax>90F, and (2) increased potential for afternoon thunderstorms across the central mountains and southern Pennsylvania. Fair and less humid conditions with seasonable temperatures appear likely Monday night through at least part of Wednesday associated with high pressure building southeast from the Grt Lks. However, there remains enough uncertainty with regard to position of stalled front south of Pa to maintain low POPs over the southern counties. The aforementioned boundary will likely lift back north as a warm front by midweek accompanied by an increasing chance of convection by late Wednesday or Thursday. There is rather strong model agreement for the passage of a potent/fairly amplified northern stream trough moving east from the upper Great Lakes later next week. Increasing upper diffluence, deep-layer shear and sharp height falls to follow point twd a few rounds of convection and a decent probability for some localized SVR TSRA centered on Thursday afternoon and evening (though a late Wed night/early Thursday morning MCS can`t be ruled out across the western half of the state. A few day period of refreshingly cooler/less humid air is likely to close out next week and will continue at least through Saturday. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Convection just about wrapped up across central PA, giving way to low-mid clouds as VFR conditions prevail with diminishing winds through the night. Southwest winds will increase toward 10 knots late Saturday morning/early afternoon with the best threat of a shower or storm being across western PA. High density altitude will be a concern through the weekend with the building heat. Outlook... Sun-Wed...CFRONT slowly drops acrs PA, sct/nmrs TS/SHRA with best chances Monday. && .CLIMATE... As the heat wave continues, especially across the Middle and Lower Susquehanna Valley, record-challenging temperatures are expected on Sunday July 24th. Here are the current records: RECORD HIGH TEMPERATURES FOR JULY 24TH Altoona (AOO) 95F* (2016) Bradford (BFD) 87F* (2001) Harrisburg (MDT) 96F* (1965, 1999, 2001) State College (STCP1) 100F (1934) Williamsport (IPT) 96F* (2001) RECORD LOW TEMPERATURES FOR JULY 25TH (Sunday night) Harrisburg (MDT) 77F* (1965) *indicates forecast high/low Sunday and Sunday night would tie or break the current record && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert/Steinbugl NEAR TERM...Lambert/Steinbugl SHORT TERM...Lambert/Steinbugl LONG TERM...Lambert/Fitzgerald/Banghoff AVIATION...Guseman/Steinbugl CLIMATE...Lambert
Area Forecast Discussion
National Weather Service Grand Rapids MI
952 PM EDT Fri Jul 22 2022 LATEST UPDATE... Update .UPDATE... Issued at 952 PM EDT Fri Jul 22 2022 No big changes needed to the going forecast this evening. We have bumped up rain chcs a bit over the SW portion of the area, as the latest near term models/CAMs indicate better coverage of showers/storms later tonight. We have a few spotty showers developing this evening over Srn Lake Michigan and IL/IN. These are indicative of the nose of the low level jet starting to strengthen and approach the area from the SW. We expect more of this scattered nature of showers, and eventually a few storms embedded. MU CAPEs are currently on the order of 500-1000 J/kg per the SPC Mesoanalyst page. These values are forecast to as high as about 2,000 J/kg late tonight after a few hours of warm and moist advection with the low level jet takes place. The latest few runs of the HRRR show that there will be almost a line of showers and storms come in after 08-09z tonight. This looks to be the case as the short wave helping to drive the low level jet comes into the 2,000 J/kg of MU CAPE. The best concentration will be toward the MI/IN border where even better instability will be present. As far as severe weather is concerned, forecast soundings indicate there will be limited shear availble with the low level jet coming in, and then relatively weak winds in the mid levels. This should keep things from becoming too strong. We can not rule out some decent hail however as mid level lapse rates around around 7.5C/km, and there is decent CAPE in the mid levels and -10 to -30C layer. As mentioned before, there are some decent DCAPE values with good low level lapse rates, and dry mid level air present. There will be a sfc inversion that will help to act as a buffer to sfc based winds. && .DISCUSSION...(This evening through next Friday) Issued at 217 PM EDT Fri Jul 22 2022 ...Potential for showers and thunderstorms tonight... A weak low level trough moves into the northern zones this evening and generates some low level convergence. There may be enough lift there to generate a few showers. Overall little or no instability will be present in that region at that for now we will only feature showers. As we go through the night though...instability builds and another low level wave moves in...this time a little further south. There is some uncertainty as to how much shower and thunderstorm coverage develops...but several high res models are showing scattered to numerous showers and thunderstorms. The main period for thunderstorms will be after midnight. This is when MU CAPE values top 1000 J/kg. With deep layer bulk shear values of around 35 knots and DCAPE values over 1000 J/kg...some organized storms with gusty winds appear possible...mainly to the south of a Muskegon to Jackson line. ...One or more rounds of strong to severe storms possible Saturday night into Sunday morning... A strong mid to upper level wave tracks eastward through the Canadian Prairies and into Ontario during this period. This leads to strengthening wind fields in zonal flow across the Upper Plains and into the Great Lakes region. At the same time a southwesterly low level jet builds into the region...advecting in a very unstable airmass. This combination of increasing deep layer shear and very unstable airmass in place will support strong to severe thunderstorms for our CWA. Guidance has been showing a 700 mb trough arriving around 06z Sunday...which looks to be about when the main risk for severe weather arrives. With pwat values shown to top 1.75 inches...locally heavy rainfall may occur. There are some indications that the initial line of storms may lay out a boundary off to the southwest of the main complex. If this happens we could see several hours of training cells which would increase the flood risk. There is a trend for the associated cold front to hang up over the CWA Sunday and not resume a southeast push until later in the morning or early in the afternoon. Based on this the showers and thunderstorms could still be numerous to start the day with some potential for organized convection during the day. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 752 PM EDT Fri Jul 22 2022 We have one, and possibly two periods of concern for impacts in this 24 hour forecast period, focused around storms. The first one will be later tonight, and the possible second one will be right toward, or just after this forecast period. We are starting out mostly clear this evening, with winds coming down off of being a little gusty this afternoon. Most of the night will remain VFR with no impacts, until about 07z or so. After 07z, we will see conditions become more favorable for shower and storm development. At first, showers will be scattered about, with an isolated storm possible. The latest short term data is indicating that more widespread showers and storms will affect the terminals after about 09z. This even could be a line of showers and storms. This will likely bring MVFR to IFR conditions for 3-4 hours. KMKG may be on the nrn fringe, and not see as bad of conditions as other sites further South. The showers and storms should move out from West to East from 11-14z or so. Skies should clear out for most of the rest of the day, until late in the period. We will be watching severe storms expected to be in Wisconsin tomorrow afternoon/evening, that will move toward the area as early as mid-evening. This is a bit uncertain yet, and has the best chance of affecting KMKG and KGRR before 00z Sun. Have handled this with a VCTS for now. This will be fine tuned with subsequent TAF issuances. && .MARINE... Issued at 217 PM EDT Fri Jul 22 2022 The pressure gradient tightens up across northern Lake MI as a wave of low pressure tracks through. This will lead to increasing winds over the nearshore water for those locations. Big Sable Point will see the strongest winds in our nearshore waters this evening as this feature passes through. With a risk for gusts over 20 knots...we will continue the small craft advisory. Late tonight a risk for several hours of gusty winds exists for much of the central and southern zones as an area of showers and thunderstorms pushes off to the east. Several models are showing gusts topping 20 knots which could lead to hazardous conditions. We will maintain the small craft advisory for these locations for later tonight into Saturday. If the winds do should the waves. Moderate swim risks are possible to start the day on Saturday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...Small Craft Advisory until 11 PM EDT this evening for LMZ849. Small Craft Advisory from 4 AM to 2 PM EDT Saturday for LMZ844>847. && $$ UPDATE...NJJ DISCUSSION...MJS AVIATION...NJJ MARINE...MJS
Area Forecast Discussion
National Weather Service Lincoln IL
905 PM CDT Fri Jul 22 2022 .SYNOPSIS... Issued at 341 PM CDT Fri Jul 22 2022 Clusters of thunderstorms are expected to develop across Iowa into northern Illinois late tonight...with some of the storms potentially reaching as far south as the I-72 corridor. After any early morning storms come to an end, oppressive heat and humidity will be noted on Saturday as highs reach the lower to middle 90s and heat index readings climb well above 100 degrees. && .UPDATE... Issued at 905 PM CDT Fri Jul 22 2022 Skies are mostly clear across the area with relatively light winds. Newest CAM runs still showing showers and storms reaching into the northern parts of the CWA overnight. Current forecast has a good handle on that, so will not be making any adjustments to the pops and wx forecast. Dewpoints have increased over the area this evening, so think overnight lows may not drop as far as forecasted. So, only adjustment made tonight will be to raise overnight lows along and north of I-74 by 1-2 degrees. Update will be sent shortly. && .SHORT TERM...(This evening through Saturday) ISSUED AT 341 PM CDT Fri Jul 22 2022 20z/3pm surface analysis shows a nearly stationary frontal boundary extending from central Iowa E/SE into the Ohio River Valley. As a 30-35kt 850mb jet develops from Kansas northeastward into Iowa after dark, scattered thunderstorms are expected to develop along the boundary across northern Iowa. These cells will track E/SE and will largely remain north of the KILX CWA tonight. Only a couple of CAMs suggest convection may develop/track as far south as I-72 well after midnight. Given the clear northerly trend, have cut PoPs significantly from previous forecast package, but may not have gone far enough as central Illinois could remain completely dry overnight if the consistent HRRR verifies. Nonetheless think chance PoPs north of I-72 are still prudent late tonight into Saturday morning. After early morning showers depart, SW winds gusting 15-20mph will transport higher dewpoint air back into the area. Given air temperatures expected to reach the lower to middle 90s and dewpoints climbing above 70, afternoon heat index values will reach 105 to 110 degrees across the board. The exception may be across the far NE along/north of a Bloomington to Danville line where effects from early morning convection to the north may still be felt. Since confidence for oppressively hot and humid conditions has grown, decided to expand the Heat Advisory to include the entire CWA. .LONG TERM...(Saturday night through Friday) ISSUED AT 341 PM CDT Fri Jul 22 2022 The next significant chance for convection will develop late Saturday night into Sunday as a cold front settles southward into the region. With SBCAPEs exceeding 3000J/kg and 0-6km bulk shear increasing to 30-35kt, scattered strong to severe thunderstorms will be possible along/ahead of the front Sunday afternoon and evening. The front will drop southward and stall near the Ohio River Sunday night into Monday. Several weak waves of low pressure tracking along the boundary will produce elevated convection north of the front through Tuesday. Exactly how far north of the baroclinic zone the showers/thunder will extend remains in question...but it appears the southern half of the CWA will continue to see rain chances through Tuesday. Areas along/north of I-72 will likely be dry. The next significant short-wave trough and accompanying cold front will arrive by the middle of the week, once again ramping up rain chances for Wednesday and Thursday. After that, a deep upper trough is progged to dig over the Upper Midwest and Great Lakes, finally pushing the boundary well south of Illinois by Friday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 645 PM CDT Fri Jul 22 2022 Believe VFR conditions will prevail at all TAF sites next 24hrs. Skies should be mostly clear at all sites this evening with maybe a little bit of cirrus. Around midnight, the cirrus will thicken in advance of a weather complex expected to move just north of I-74 overnight. Will keep VCTS at PIA and BMI for about 4-5hrs in the early AM and then just have VCSH at CMI for a few hours. SPI and DEC should remain dry. The precip will move through quickly and scattered cirrus will cover the sites and the rest of central IL tomorrow afternoon. Winds will be south to southwest through the period with speeds under 10kts tonight and tomorrow morning. Speeds will increase during the afternoon with gusts around 20kts. && .ILX WATCHES/WARNINGS/ADVISORIES... Heat Advisory from noon to 8 PM CDT Saturday for ILZ027>031- 036>038-040>057-061>063-066>068-071>073. && $$ UPDATE...Auten SYNOPSIS...Barnes SHORT TERM...Barnes LONG TERM...Barnes AVIATION...Auten
Area Forecast Discussion
National Weather Service Indianapolis IN
1128 PM EDT Fri Jul 22 2022 ...Updated Aviation Discussion... .Forecast Update... Issued at 956 PM EDT Fri Jul 22 2022 Surface analysis this evening shows strong high pressure in place over the southeastern United States. This was resulting in a continued warm and humid southerly gulf surface flow of air into Central Indiana. Dew points remained in the middle to upper 60s. Aloft, water vapor imagery showed mainly NW flow in place. A weak disturbance was found over nrn IL and southern WI, producing isolated thunderstorms. Forecast soundings and time heights show a dry column overnight. HRRR suggests convective development in the next 1-2 hours over IA, with propagation expected toward Central Indiana late tonight and early on Saturday morning. Confidence remains low for this development as GOES16 shows dry and subsidence in place over IA and only a few passing CU clouds. Across IL, the isolated storms should remain well north of our forecast area. Thus expect a dry night overnight. For collaboration purposes, have kept minimal pops overnight across the northern parts of the forecast area, but again confidence in that remains quite low. Given the dew points creeping higher with the lack of mixing, trended overnight lows toward the lower 70s, not much change from the previous forecast. && .Short Term...(This evening through Saturday night) Issued at 304 PM EDT Fri Jul 22 2022 Hot and dry weather continues today with only a few passing clouds as of this afternoon. Satellite water vapor shows that moisture has been increasing through the atmosphere today and will continue to do so ahead of an advancing upper short wave. This wave will bring forcing to the area and a chance of PoPs moving in from the north starting early tomorrow morning. CAMs are trending towards a later start to the chance of showers and storms for our area as compared to previous runs. The later start time seems more probable given the amount of dry air and subsidence there is to overcome. Precipitation will continue to be possible for the northern to northeastern half of the forecast area into tomorrow afternoon as the short wave progresses eastward. Some uncertainty with this system comes with how the associated surface low will track... models agree that it will generally go from northern Illinois towards central Ohio but some solutions have it staying more over northern Indiana while others show a track closer to central Indiana. While a subtle difference, where and how far south into the CWA precipitation reaches will be dependent on the path the low takes. Given this, limiting PoPs to chance for now. Tomorrow is expected to be a little hotter than we`ve seen the last few days due to WAA as surface flow will be out of the south to southwest. There will also be moisture advection allowing for more humid and uncomfortable conditions. For now, not anticipating the need for a heat advisory tomorrow but it would not be out of the realm of possibility that counties in south central Indiana could need it later on. Cloud coverage will increase through the period but should the clouds stay on the thinner side across the south or the dew points get higher tomorrow than anticipated, the likelihood that heat indices get above 105 degrees for that area will be higher. Winds are expected to gust to around 15 to 20 mph through the day tomorrow which should allow for at least some relief for the heat and humidity. There will be a brief period from Saturday evening to late Saturday night with no chance of precipitation but the next chance comes at the tail end of the short term as a stronger system starts to impact the area. && .Long Term...(Sunday through Friday) Issued at 304 PM EDT Fri Jul 22 2022 Highlights: * Daily rain chances for periods of the extended * Gradual temperature decrease as a boundary moves through next week. Sunday: Sunday will be the only day under the influence of a mid level ridge, as weak WAA helps build heights aloft. The main impact will be oppressive heat over the region. This in combination with a subtle moisture return, observed by dew points in the low 70s, will result in heat index values above 100 across all of central Indiana including some region in the upper 100s. Confidence is increasing in high heat, as peak diurnal warming looks uninhibited; however, will hold off on headlines for now as prior day upstream confection could impact conditions Sunday morning One of a few weekend MCSs over the Great Lakes will approach central Indiana Sunday morning, but the emergence of broad subsidence in the right exit region of the upper level jet should hinder its progression, keeping rainfall and associated cloud cover to the north. Near the surface, a remnant boundary from the aforementioned MCS will linger over the region, and providing a source of lift for convection in the evening as the LLJ strengthens, and the EML inversion decreases. There is still many uncertainties on where this boundary will be located Sunday evening, thus PoPs have been kept below 40. Dynamically, there looks to be nothing keeping convection from organizing, especially as shear increases along the LLJ. This could lead to severe weather, and will need be monitored in the coming days. Monday through Wednesday Multiple rain/thunderstorm chances will be the main focus for early next week. A succession of vorticity maximums will be advected into the region, spurring weak shortwaves through the Ohio Valley. Near the surface, a quasi-stationary front should be generally over the region, providing some organized forcing for convection. Ensemble members are widely spread on convective initiation timing/location, and therefor the forecast is for low chance PoPs through this period. As the forecast nears, confidence should increase, providing more detail on where rain is expected. With multiple chances of precip, and Pwats above 1.5" throughout the period, flooding could be of concern in locations that receive multiple rounds of rain. Temperatures should decrease slightly with cloud cover increasing within prior day upstream convective cirrus and present day altocu. Still the overall airmass will be rather warm; highs in the upper 80s, along with dewpoints near 70. Thursday and Friday: By the end of the week, a shift in the pattern is expected. Ensembles are fairly aligned on a more dominant trough providing elongated CVA, pushing the overall pattern to the E. A cool push of NW flow behind this through should progress the boundary southward, providing relief from the hot conditions for a short stretch. This also should be a fairly dry period with weak lapse rates below 5km and no synoptic scale forcing for ascent. && .Aviation...(06Z TAF Issuance) Issued at 1127 PM EDT Fri Jul 22 2022 Impacts: * VFR Conditions are expected this TAF period. * Very Low Confidence for an Isolated Thunderstorm after 10Z in the vicinity of LAF. Discussion: Little overall change since the previous discussion. High pressure southeast of Central Indiana will remain the dominate feature in Indiana/s weather overnight. Skies were mostly clear across Central Indiana. Models suggest thunderstorm development over southern WI/NRN IL overnight...but the coverage of this has been minimal. Propagation of this feature should remain well north of the TAF sites, should storms become more widespread. Confidence for additional TSRA development overnight remains low as models appear to have timing and positioning difficulties and minimal development remains present. Best chances for development remains well north of Central Indiana along a boundary stretching from Central IA...across NRN IL to northern Indiana. On Saturday...a dry column is shown again within the forecast soundings along with convective temperatures in the upper 90s. Thus another mostly sunny, hot summer day with VFR conditions and southerly winds due to the strong surface high to the southeast. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ Update...Puma Short Term...KH Long Term...Updike Aviation...Puma
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1103 PM CDT Fri Jul 22 2022 .UPDATE... Issued at 924 PM CDT Fri Jul 22 2022 This afternoon`s forecast seems to be on track this evening. With ample instability in the area, convection was able to initiate this afternoon in southeastern and east-central Missouri. As anticipated, this activity died as it lost solar heating. Tonight, a lobe of vorticity moving into the northern Midwest will help spark convection over Iowa. A cluster of thunderstorms is expected to form and move along an instability gradient southeast through Illinois. This track should keep activity just northeast of the CWA as reflected in the 00z CAM guidance. Slight chance PoPs have been kept in our northernmost counties to account for any showers or thunderstorms that may skirt the periphery of the CWA. Jaja && .SHORT TERM... (Through Sunday) Issued at 303 PM CDT Fri Jul 22 2022 Dangerous heat is still expected over the area through early Sunday evening. Made no changes to going advisories. Temperatures are climbing quickly this afternoon under full July sunshine across the area with 2 pm readings including 100 degrees at Jefferson City and Columbia amd 98 at Chesterfield. Most other locations in the CWA are in the 90s or soon will be. Latest surface analysis is complicated, with two fronts, one extending from western Iowa through northern Missouri into southern Illinois and another extending from southern Missouri into the Mid South. The combination of soil conditions and moisture convergence along the fronts is causing dewpoints to vary greatly across the area which in combination with the temperatures, is causing heat indices to also vary. HREF as well as the NAM/GFS is showing the center of the upper high moving east into the Mid South by Sunday. Temperatures at 850mb will increase into the 24-27C range which is consistent with going highs in the 97-104 range on Saturday. It still looks like a front will move south into the northern part of the CWA on Sunday as shortwave trough moves through the Upper Midwest. While this may bring some relief to the north part of the CWA, forecast guidance still supports highs in the upper 90s to 103 south of the front on Sunday. The combination of the heat and dewpoints will support heat indices in the 105-110 range both days. Will keep a slight chance of thunderstorms over the eastern Ozarks late this afternoon into this evening as CAMS and HREF guidance still suggests that there will be some development over this area. Cumulus field has yet to develop and RAP soundings show a cap, so any thunderstorms should be isolated. Will continue with a slight chance for showers and thunderstorms late tonight as a weak shortwave moves just north of the CWA. Better coverage of showers and thunderstorms will occur with the front Saturday night and Sunday night as a front moves south into the area. Britt .LONG TERM... (Sunday Night through Next Friday) Issued at 303 PM CDT Fri Jul 22 2022 Ensemble means support the GFS and ECMWF solutions that the upper high will be suppressed south into the southeastern CONUS by the middle of next week. This will occur at the same time that a shortwave trough will move across the Midwest on Tuesday, followed by a deeper trough that will drop south into the Great Lakes on Thursday. This pattern will keep a chance of showers and thunderstorms in the forecast Monday through Thursday as a quasi- stationary front will remain somewhere across Missouri and Illinois. By the end next week, the front may be pushed south of the area in response to the front deepening over the Great Lakes. Temperatures are not expected to be as warm next week with the front in the area and the chance of rain. There will be some variability in the temperatures and this is reflected well in the NBM and GEFS guidance plumes which show a notable spread for summer next week. Britt && .AVIATION... (For the 06z TAFs through 06z Saturday Night) Issued at 1103 PM CDT Fri Jul 22 2022 The period should remain dry and VFR for every terminal except KSUS. Fog is currently impacting this site with visibility down to 6SM. As humidity increases overnight, visibility is expected to drop to 4SM before rising again after about 09z. LLWS is possible Saturday morning near sunrise for KUIN, but it is too marginal to mention in the TAFs at this time. Otherwise, winds are expected to change to southwesterly by Saturday and increase in speed, becoming gusty everywhere except KSUS and KCPS in the afternoon. These gusts should die as the sun sets. Jaja && .LSX WATCHES/WARNINGS/ADVISORIES... MO...IL...&& $$ WFO LSX
Area Forecast Discussion
National Weather Service Nashville TN
837 PM CDT Fri Jul 22 2022 ...New UPDATE... .UPDATE... Issued at 822 PM CDT Fri Jul 22 2022 The very widely scattered late afternoon convection that Popped up across the south is done for the night. Updated the grids to remove the small chance of pops that were added previously. With the strengthening 500 mb ridge Clarksville was able to reach 102 this afternoon...John Tune 100...and Dickson COOP site 101. BNA only reached 98. With the ridge getting even stronger tomorrow it should be a few degrees warmer. Of a slight note...CONShort and HRRR both show some late afternoon convection possible tomorrow. Don/t really expect this to play into the high temperature forecast too much...however if a shower were to fall over an observing site this could keep the temperature a degree or two cooler. && .SHORT TERM... (This afternoon through Sunday) Issued at 204 PM CDT Fri Jul 22 2022 It`s quite toasty outside today thanks to a strengthening H5 ridge overhead, which has kept cloud formation minimal. Ample sunshine and mixing has allowed temperatures to reach the upper 80s to around 90 on the Plateau, low to mid 90s east of I-65, and mid 90s to around 100 west of I-65. In fact, Clarksville just hit 100 degrees as of last check, which is the 7th day this year it`s been in the 100s there. It`s possible Nashville could reach 100 as well, but mixing has not been as strong as in our northwest counties so it may come up just short. Upper ridge strengthens a bit more tomorrow so anticipating highs a degree or two higher than today, with Nashville likely hitting the century mark and Clarksville getting even higher than that. Hotter temps plus an increase in dewpoints gives heat indicies ranging from 102 to 108 west of the Plateau tomorrow afternoon, so went ahead and issued a heat advisory accordingly. HRRR suggests an isolated shower or storm could pop up tomorrow afternoon, but chance seems too low to add a pop into the forecast. Ridge remains in place on Sunday as well with an additional increase in low level moisture, so another heat advisory is likely. However, most guidance indicates isolated showers and storms will pop up over at least our southern and eastern counties during the afternoon, which would throw a wrench in some areas reaching heat advisory criteria - and I held off on an advisory for now. && .LONG TERM... (Monday through next Friday) Issued at 204 PM CDT Fri Jul 22 2022 Pattern change begins for us on Monday as the H5 ridge begins to get squashed to the south, thanks to the polar jet stream shifting down into the Midwest and Great Lakes. This will push a weak boundary southward towards the midstate Monday into Tuesday. Moisture pooling ahead of the boundary with bring PWATs up to over the 2 inch mark, especially over our north, and anticipate some scattered showers and storms to pop up both days with highest pops over the north and lowest south. NBM precip chances seem a bit on the high side and have undercut them slightly. Forecast soundings show moderate MLCAPE, ample DCAPE, and weak shear, so a few strong storms with wet microbursts are possible both days. Cloud cover and precip will knock highs down several degrees Monday and Tuesday, but it`s possible guidance is overdoing this "cooldown" due to the strength of the upper ridge, and I went a little above NBM numbers. Upper ridge shifts further southward from Wednesday onward with the aforementioned boundary shifting closer to or into Middle Tennessee. This will keep fairly high daily pops going the rest of the forecast period. However, it will remain toasty with plenty of humidity and highs staying well above normal. && .AVIATION... (00Z TAFS) Issued at 621 PM CDT Fri Jul 22 2022 VFR conditions are expected to prevail for the taf period. There is a chance CSV/MQY/CKV could see a brief period of IFR/MVFR fog near dawn. An isolated shower or storm could impact a terminal late Saturday afternoon, but chances are too small to include the mention of VCTS. Winds will generally be out of the south at 5 kts or less. && .PRELIMINARY POINT TEMPS/POPS... Nashville 74 100 77 99 / 0 10 0 10 Clarksville 72 101 76 100 / 0 0 0 10 Crossville 68 91 70 90 / 0 10 10 10 Columbia 72 98 74 98 / 20 10 10 10 Cookeville 71 95 73 94 / 0 0 10 10 Jamestown 68 92 71 89 / 0 0 0 10 Lawrenceburg 72 97 73 96 / 20 10 10 10 Murfreesboro 72 99 75 98 / 20 10 10 10 Waverly 72 101 75 99 / 0 0 0 10 && .OHX WATCHES/WARNINGS/ADVISORIES... Heat Advisory from 11 AM to 7 PM CDT Saturday for Bedford-Cannon- Cheatham-Clay-Coffee-Davidson-De Kalb-Dickson-Giles-Hickman- Houston-Humphreys-Jackson-Lawrence-Lewis-Macon-Marshall-Maury- Montgomery-Overton-Perry-Putnam-Robertson-Rutherford-Smith- Stewart-Sumner-Trousdale-Warren-Wayne-White-Williamson-Wilson. && $$ UPDATE.......12 SHORT TERM...Shamburger LONG TERM....Shamburger AVIATION.....Reagan
Area Forecast Discussion
National Weather Service Paducah KY
620 PM CDT Fri Jul 22 2022 .UPDATE... Updated aviation section for 00z taf issuance && .SHORT TERM...(Tonight through Sunday night) Issued at 252 PM CDT Fri Jul 22 2022 The upper ridge will continue to build over the Quad State region through Saturday and linger through Sunday. Sunday night a storm system moving through Ontario and the Great Lakes will attempt to suppress the ridge a bit. At the surface, southwest winds will be the rule through Sunday and then a cold front will attempt to move southward into the region Sunday night. There will be no changes to the Heat Advisory for the weekend. Dewpoints are once again climbing into the middle 70s over southeast Missouri and southern Illinois, well above what any guidance expected. This is good for the somewhat marginal Advisory today, but could be a sign of more intense heat over the weekend, if the same trend holds. The GFS and ECMWF ensembles are not indicating significant moist anomalies in the low-levels as we saw on Wednesday and earlier in July, so confidence is not great in the mid to upper 70 dewpoints developing again Saturday or Sunday. However, with the cold front approaching on Sunday it would make some sense for dewpoints to pool over our region. We stuck very close to the NBM temperatures and dewpoints through Sunday night, which generally represents the worst case heat and humidity. This puts heat indices across the entire region comfortably into Heat Advisory territory Saturday and even takes the KCGI to KMDH corridor over 110 on Sunday. We certainly cannot rule out an upgrade for portions of the region Saturday or especially Sunday. However, for now there will be no changes to the heat headlines. The 18Z HRRR has backed off on the potential for some showers or storms to move southeast into southeast Missouri and southern Illinois this evening. However, prior runs and a few other members of the 12Z HREF did push a few convective elements into our area. Decided to keep the slight chance PoPs and even lingered them a bit longer into the evening and deeper into the area. The consensus of guidance keeps the cold front and any associated convection north of the Quad State Sunday afternoon, but later Sunday night the front or convective outflow will likely reach at least the I-64 corridor, so we have 20-40% PoPs from south to north across the region mainly overnight. The flow will remain weak, so severe storms are not anticipated. Locally heavy rainfall and lightning will be the primary threats. .LONG TERM...(Monday through Friday) Issued at 252 PM CDT Fri Jul 22 2022 The medium range models continue to indicate that as two main lobes of energy aloft near the Canadian border move through the pattern during the extended forecast period, mid level height falls will impress themselves on the flat ridge that has taken up residence over the southern half of the CONUS. One such wave will affect the PAH forecast area on Mon as a surface frontal boundary sinks southward, stalls Mon night, and begins to move northward on Tue. The front is expected to be the main lifting mechanism for shower and tstm development in the moist and unstable airmass across our region Mon, first in the northern half of the region, then will move progressively farther south through Mon night. An impulse in the mid level flow on Tue should keep shower and tstm activity fairly common at least through midday, possibly waning during the afternoon hours as the front moves north and clears our region. Overall, the best PoPs with this system will be in the eastern parts of the region and the least PoPs will be in southeastern MO where the frontal boundary will be more diffuse. After a bit of a lull Tue night and Wed, with isolated to scattered PoPs, limited tstm coverage, and limited QPF, the next system in the form of a mid level wave and another surface front will ramp up the chances of pcpn again for late in the week. Model consensus suggested at least 50% PoPs starting in the northernmost tier of counties late Wed night and spreading areawide on Thu, especially in the afternoon. Tstm coverage should taper off Thu night, followed by an overall diminishment of showers and tstms Fri as the surface wind shift to the north will be well underway. At this time, we are not seeing a signal for the surface dewpoints to get out of the lower 70s. Therefore, while peak temps are expected to be somewhat cooler in the extended, with the exception of Wed, heat indices may creep up above 100 degrees in the southern half of the region Mon through Thu afternoons (especially true in parts of southeastern MO where temps will tend to be the warmest). Wed may yield heat indices of 105+ mainly in the western half of the region. Lows should remain in the lower 70s, except perhaps upper 60s in the northern third of the region. && .AVIATION... Issued at 620 PM CDT Fri Jul 22 2022 No cigs or vsby restrictions are forecast. However, there is a chance of some mvfr vsbys in haze or fog late at night. This is what occurred last night, but slightly stronger winds tonight should tend to limit fog or haze. A few diurnal cumulus clouds with bases above 4k feet agl are expected from midday into late afternoon. Winds will be southwest, up to 10 kt in the afternoon hours and nearly calm late at night. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...Heat Advisory until 8 PM CDT Sunday for ILZ075-080-081-084-085- 088-089-092-093. Heat Advisory from 11 AM Saturday to 8 PM CDT Sunday for ILZ076>078-082-083-086-087-090-091-094. MO...Heat Advisory until 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 until 8 PM CDT Sunday for KYZ004. Heat Advisory from 11 AM Saturday to 8 PM CDT Sunday for KYZ001>003-005>022. && $$ SHORT TERM...DRS LONG TERM...DB AVIATION...MY
Area Forecast Discussion
National Weather Service Portland OR
243 PM PDT Fri Jul 22 2022 .SYNOPSIS...Aside from patchy drizzle along the coast, expect mild and dry conditions through this weekend. An extended stretch of hot weather will grip the region next week. && .DISCUSSION...Through next Friday...Tonight, the OTH-GEG pressure difference is forecast by the NAM, GFS, and RAP to remain +7mb to +9mb, though it`s also forecast to weaken throughout the night. This will again support a marine push, though all guidance is pointing to a shallower layer compared with last night. A slight chance for drizzle has been added along parts of the coast tonight, given (1) forecast soundings are suggesting negative omega coinciding with a shallow layer of instability within the ~1.5-2kft layer and (2) it`s only a slight chance, which means the probability it won`t occur is 4 times higher than the likelihood it will. Given the stratus is expected to be less deep tomorrow morning, surface heating will burn it off a little sooner allowing for more efficient boundary layer warming. Highs will therefore rebound a little into the upper 70s to low 80s inland Saturday (warmest in the southern Valley), but with a weak upper trough passing to our north across Washington 500hPa heights remain in the mid 580s dam across NW Oregon and SW Washington. Heights begins to gradually rise Sunday, but the area remains in the saddle point between two upper level ridges - one to our northwest and another to our southeast - until Tuesday when those two features connect and the mean of the ensemble guidance brings 500hPa heights to above 5920m. By late Wednesday, more than 20 (40%) of the EPS`s members and more than 40% of the CMCE`s members bring 500hPa heights to more than 594dam (2 sigma above the climatology for this time of year) to areas south of Salem in our CWA, which supports the notion that Wednesday and Thursday will be the hottest days in the forecast. However, the GEFS remains much cooler overall, and less than 10% of its members suggest such an anomalously deep atmospheric column in NW Oregon. Still, the mean in the ensemble yields surface high temperatures in the mid 90s through Saturday, which adds to our confidence in a prolonged, area-wide stretch of temperatures 10+ degrees above climatology. NBM`s spread has decreased slightly over the past 24 hours. Now, it yields less than a 10% probability for high temperatures less than 90F at PDX Wednesday through Friday, but greater than a 30% chance for highs over 100F on each of the same days. It will be difficult to get temperatures more than a degree or two above 100F anywhere in our CWA any day next week given the surface pattern, which is characterized by a thermally induced trough extending northward across the Willamette Valley and into south Washington, favors onshore flow. It seems reasonable that the likelihood for triple digits will increase throughout the week as this onshore flow promotes increasing dewpoints and thus increasing nocturnal low temperatures, which would serve as a better spring board off of which solar heating will warm the surface each day. This lack of overnight cooling, which will be most pronounced in urbanized areas due to the urban heat island effect, will be most problematic for those without AC who are counting on relief to come in the early morning hours. Record overnight lows are in the upper 60s for this time of year, and our forecast features mid 60s for most locations, with considerable uncertainty; the NBM gives around a 30% for 70+ degree lows on both Thursday and Friday mornings. Though no particular day stands out as extreme in terms of heat, it`s going to be a prolonged stretch of hot weather, so we want to emphasize the need for folks to be careful. Stay in an air- conditioned place as much as possible, drink plenty of water, check on your neighbors, and look after your pets and little ones. Never leave a child, disabled person, or pet in a hot vehicle. One thing of note: The deterministic GFS, in its 06z and 12z runs, suggests a dynamic shortwave to impact the Pacific Northwest Thursday night, which could theoretically spark some convection over the Cascades, where NBM (during the same time period) has a 7% chance for thunder. Though it would be imprudent to trust a specific deterministic model in the long-range when it is so well outnumbered by other members of the ensemble suite which suggest a different outcome (i.e., no thunder and no QPF), we will be paying attention to both the GFS and other ensemble guidance as it pertains to convective potential during the extended period as new iterations of guidance come in. -Bumgardner && .AVIATION...00Z TAFs: At 20Z visible satellite imagery showed the marine stratus and stratocumulus gradually thinning. MVFR conditions continue along the coast and will likely persist through Saturday morning. High-resolution model data suggests the south Washington and north Oregon coastal areas will likely remain MVFR through the 18Z Saturday. There is a chance that cigs could briefly rise just above MVFR thresholds late this afternoon through mid-evening. Cigs 030-040 to continue over much of the interior lowlands through early Friday evening. Coverage area diminishes through the remainder of the evening. However, expect areas of marine stratus to return after 06Z Saturday, especially along the Columbia River. The marine layer Saturday morning should not be as deep or extensive compared to this morning. Areas of MVFR to persist through about 19Z, mainly along the Columbia River and the lower slopes of the south Washington and north Oregon Cascade foothills. For detailed Pac NW aviation weather information, go online to: KPDX AND APPROACHES...Low-end VFR at the terminal and vicinity as of 20Z. Local stratus break-out program suggests dissipation to SCT clouds will not occur until around 23Z. VFR to prevail from 00Z Saturday through about 10Z. Expect MVFR cigs to return late Friday night and persist until 18Z Saturday. Weishaar && .MARINE...Surface high pressure will be the dominant feature over the waters for the next several days. This will result in a typical northwest to north wind pattern through early next week. The thermally-induced surface trough over the north California and south Oregon waters will strengthen Saturday afternoon and then expand a little more north Saturday night through Sunday. Model guidance suggests 20-25 kt boundary layer wind speeds over the waters south of Cascade Head beginning mid to late Saturday afternoon. These speeds eventually spread into the northern outer waters by 00Z Sunday. Will issue various small craft advisories with this package, primarily for wind. Advisory conditions can be expected to persist through 07Z Sunday for the southern inner waters and to 12Z Sunday for all outer waters. Wind speeds gradually start to diminish late Sunday night and fall below advisory thresholds Monday. Will likely need another round of small craft advisories Sunday afternoon through Monday morning, especially for the outer waters. Overall general wind speeds fall to 10 kt or lower late Monday night or Tuesday morning and remain there through late in the week. Seas will be primarily wind-driven with a fresh swell component. Guidance shows wave heights generally in the 4 to 6 ft range at least through early next week. There is a high probability that seas will reach 7 ft over the south zones Saturday afternoon through Monday. Forecast wave periods of 7 to 8 seconds will result in steep and choppy conditions. Even though wind speeds are expected to fall below advisory criteria late Sunday night or Monday, seas of 6-8 ft at 6-8 seconds will create dangerous conditions for smaller craft necessitating the need for continued or new advisories. Weishaar For information about upcoming marine zone changes, go online to: && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory from 8 PM this evening to 5 AM PDT Saturday for coastal waters from Cascade Head OR to Florence OR out 60 nm. Small Craft Advisory from 2 PM Saturday to midnight PDT Saturday night for Coastal waters from Cascade Head to Florence OR out 10 nm. Small Craft Advisory from 5 PM Saturday to 5 AM PDT Sunday for Waters from Cape Shoalwater WA to Cascade Head OR from 10 to 60 nm. Small Craft Advisory from 2 PM Saturday to 5 AM PDT Sunday for Waters from Cascade Head to Florence OR from 10 to 60 nm. && $$ Interact with us via social media:
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
757 PM EDT Fri Jul 22 2022 .UPDATE... Issued at 757 PM EDT Fri Jul 22 2022 Southeast flow today led to thunderstorms building towards the west coast through the afternoon, with a few strong storms developing along sea breeze and outflow boundaries. One report was received of severe winds in Pinellas County as well as a few small hail reports during the afternoon. A line of thunderstorms is still moving northwest through the Nature Coast and Tampa Bay area along the sea breeze collision, and a few isolated storms are lingering inland south of the Interstate 4 corridor. HRRR is showing some lingering convection possible through around midnight, then mostly rain free conditions will hold through the morning. No significant forecast changes are planned for the evening update. && .AVIATION... (00Z TAFS) Issued at 757 PM EDT Fri Jul 22 2022 Thunderstorms will clear out during the next couple of hours, with VFR conditions holding through Saturday morning. Another round of thunderstorms are expected by mid to late Saturday afternoon, with periods of reduced flight categories possible at area terminals. && .MARINE... Issued at 211 PM EDT Fri Jul 22 2022 Southeast flow will continue for the next few days with a turn onshore with the sea breeze in the afternoon. No headlines are expected, though winds and seas will be higher in thunderstorms, which are expected over the waters later in the afternoon/evening. && .FIRE WEATHER... Issued at 211 PM EDT Fri Jul 22 2022 No fire weather concerns as relative humidity values will remain above critical levels. Scattered to numerous showers and thunderstorms are expected each day. No significant fog is expected. && .PRELIMINARY POINT TEMPS/POPS... TPA 79 95 79 94 / 50 60 20 60 FMY 77 94 77 94 / 50 70 20 60 GIF 77 96 76 94 / 40 50 10 60 SRQ 75 93 75 93 / 50 60 20 60 BKV 73 94 73 94 / 30 50 20 60 SPG 79 93 79 92 / 50 60 20 60 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ UPDATE/AVIATION...Fleming MARINE/FIRE WEATHER....Carlisle