Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/20/22

Area Forecast Discussion
National Weather Service Bismarck ND
924 PM CDT Tue Jul 19 2022 .UPDATE... Issued at 923 PM CDT Tue Jul 19 2022 Only change for this evening was to extend POPs for a few more hours, though the past few scans has shown the showers are now starting to dissipate. UPDATE Issued at 841 PM CDT Tue Jul 19 2022 Allowed the wind advisory to expire last top of the hour at 8 pm CDT. Winds continue to decrease. No other updates. UPDATE Issued at 642 PM CDT Tue Jul 19 2022 Gusty winds continue across western and central North Dakota early this evening, especially for southwest and south central areas of the state. Winds will remain gusty through 01Z (8 PM CDT) based on latest BUFKIT soundings, and latest obs don`t show any signs of letting up, so will extend the wind advisory for another hour. Expected a rapid decrease then in wind speeds between 01 and 02Z (8-9PM CDT) as the mixed layer decreases as the sun begins to set. Will also maintain to low POPs over my east through early this evening. && .SHORT TERM...(This evening through Wednesday) Issued at 332 PM CDT Tue Jul 19 2022 An upper level low located over northeastern North Dakota continues to progress eastward into Minnesota. Convection associated with the upper low continues to form, but is not expected to be severe due to a lack of instability. Showers are thunderstorms are expected to linger across north central and northeastern North Dakota through the afternoon. A tight pressure gradient from the upper low and subsidence on the backside of the low has mixed advisory level winds to the surface. High winds are expected to continue across the southern portion of North Dakota through the evening. Skies will begin to clear west to east as the low exits the region. This will lead to optimal radiational cooling and pleasant overnight low temperatures in the upper 50s to lower 60s. Northwesterly flow becomes the dominant synoptic feature as an embedded short wave is expected to makes it`s way through the state tomorrow afternoon. In addition, afternoon mixing is going to promote breezy conditions across the state. Instability increase tomorrow afternoon as temperatures warm into lower 90s as a weak low level thermal ridge builds over central South Dakota. MU CAPE values near 1500j/kg with little to no CIN and +30kts of effective shear could support an isolated strong to severe thunderstorm. Some of the CAMs have convection initiating over central North Dakota moving east of the CWA tomorrow evening. However, some of the global models and the HRRR has little to no convection. The big question for tomorrows convection is if the forcing mechanism (short wave trough) is strong enough to initiate storms. .LONG TERM...(Wednesday night through Tuesday) Issued at 332 PM CDT Tue Jul 19 2022 Temperatures stay elevated across the region as a strong upper level high sits over the Four Corners. This will lead to upper level ridging over the Northern Rockies and northwest meridional flow over the Northern Plains. Although, a low level thermal ridge will build over the central plains increasing temperatures throughout the plains. Temperatures are forecast to hoover in the upper 80s to lower 90s for the central and southern part of the state through the work week. Northwesterly flow and warm temperatures will mix breezy winds to the surface during the afternoon hours throughout the week. Precipiation chances increase this weekend as an upper level low is forecast to move through the Pacific Northwest dampening the upper level ridge. The weekend system will decrease temperatures into the upper 70s to lower 80s making it a pleasant weekend. The pattern remains active in the extended as the region transitions to a zonal pattern with another upper low expected next week. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 642 PM CDT Tue Jul 19 2022 Some low VFR/MVFR cigs remain possible early this evening for KJMS. Otherwise the sky will trend SKC with VFR flight conditions through Wednesday morning. An increase in clouds and a chance of showers and isolated thunderstorms are then expected over the east Wed afternoon, mainly impacting KJMS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...NH SHORT TERM...Johnson LONG TERM...Johnson AVIATION...NH
Area Forecast Discussion
National Weather Service Birmingham AL
827 PM CDT Tue Jul 19 2022 .UPDATE... Evening Update. && .SHORT TERM... /Updated at 827 PM CDT Tue Jul 19 2022/ Rest of tonight. No severe is expected for the rest of tonight as we slowly lose the heat of the day. However, there may be a few showers and a storm or two at times as bits of energy continue to traverse the upper shortwave that extends from E TN and back into GA and AL. No major changes were made to the lows for tonight, in the lower to mid 70s as our airmass moderates. Some cloud cover is expected to remain behind the convection tonight as well. 08 Previous short-term discussion: /Updated at 129 PM CDT Tue Jul 19 2022/ Through This Afternoon. An upper-level trough axis continues to shift east across the area with more of a westerly flow pattern in the lower levels. This is yielding another complex forecast in which the better large scale ascent is shifting into Georgia, yet waves of energy aloft continue to produce scattered showers and thunderstorms. Thermal boundaries ,leftover by early morning activity, are likely to contribute to focused areas of additional scattered convection this afternoon with highest PoPs generally near and east of I-65. Also watching seabreeze activity across south AL which is generating a northward advancing outflow boundary. This boundary will also serve as a focus area for vertical growth across our southeast counties. Dewpoints in the lower 70s and temperatures in the 90s is resulting in MLCAPE of 2500-3000 J/kg. DCAPE is also ranging from 1000-1200 J/kg, according to RAP mesoanalysis, so any locally robust updrafts that develop this afternoon could pose a risk of damaging wind gusts and/or a few isolated instances of large hail in the strongest storms. Tonight Through Wednesday. Some lingering convection may continue overnight with PoPs decreasing throughout the day tomorrow as the trough shifts further east, and drier tropospheric moisture moves in from the west. Best chances for isolated to scattered activity will focus across our far eastern counties. With the expectation of more sun and less rain, expect warmer temperatures and highs in the mid 90s, especially west. Dewpoints will remain about the same, in the lower to mid 70s. This will result in a few hours where heat indices may rise to or just below 105 degrees, so a Heat Advisory will be in effect tomorrow afternoon for much of our western counties. 86 .LONG TERM... /Updated at 238 PM CDT Tue Jul 19 2022/ The previous forecast reasoning holds well with the forecast this afternoon. It appears we may need a Heat Advisory for Thursday as heat indices west of I-65 are in the 105-107 degree range and lower east. Will evaluate another cycle and possibly add a day. The forecast highs drop on Friday along with the heat indices. This will not last beyond one day as the heat and humidity return Saturday and beyond. Severe weather remains a threat on Thursday and will keep the wording and mentions the same. The moisture content in combination with the enhanced updrafts, added mention of locally heavy rain. Otherwise, rain chances continue each afternoon with the highest pops Thursday and Friday. 75 Previous long-term discussion: /Updated at 315 AM CDT Tue Jul 19 2022/ Thursday. A strengthening low-level ridge is expected to build into the Gulf of Mexico, generally extending from the Western Atlantic on Thursday morning. This will coincide with a residual mid-level disturbance departing to our south with mid- to upper-level ridging building from our West. Southerly to southwesterly low-level flow will continue across the Deep South as a shortwave trough/frontal system moves south toward the Tennessee Valley. Higher theta-e content will establish across the forecast area ahead of the advancing surface trough/front by Thursday afternoon. The combination of heat and humidity will likely tip the scales into Heat Advisory criteria, particularly for areas along and west of I-65. The moist, unstable boundary layer will also support strong to severe thunderstorms Thursday afternoon and evening. With dewpoints in the low to mid 70s and temperatures in the 90s ahead of the advancing front, MLCAPE will exceed 3,000 J/kg at times. Forecast soundings suggest lower mid-tropospheric RH values, as well as decent mid-level lapse rates (~6.5 C/km). This will foster high values of DCAPE whilst PWs remain elevated (1.8-2.1"). Despite eff. bulk shear <20 kts, robust convection could develop with the threat of wet microbursts early in the convective cycle, generally before cold pool aggregation occurs later in the evening. Some of the strongest updrafts could support marginally severe hail as well. Nonetheless, the severe weather threat will be added to the HWO in tandem with the ongoing/aforementioned heat. Outlying convective scenarios could also lead to locally heavy rainfall, but confidence is too low for HWO mentioning at this time. Friday through Monday. By Friday morning the surface front should have pressed farther south. This will move more favorable moisture content/forcing for afternoon convection south of I-20; it`s here where best PoPs remain forecast. (It`s possible PoPs north of I-20 will need to be decreased at some point.) We`ll need to keep an eye on convective parameters for Friday as well. Either way, low-level ridging further strengthens across the region on Friday, and mid- to upper-level ridging becomes more prominent in the Southeast as well, especially by Saturday as the persistent ridge out West flattens out. This led to a decrease in PoPs and an increase in diurnal temperatures. Low-amplitude ridging could persist in the region through the end of the period with at or above average temperatures. High temperatures in this timeframe are currently forecast to be in the mid to upper 90s with 500 mb heights increasing to ~595 decameters by the weekend. This could get us into an extended period of Heat Advisory criteria Saturday through Monday, and this will be added into the HWO. 40/Sizemore && .AVIATION... 00Z TAF Discussion. There are a few lingering showers/storms along/S of the I85 corridor that may affect MGM/TOI for the next 2-3 hrs. Otherwise, precipitation chances should lower for the remainder of the night after sunset. Another bit of energy associated with the upper shortwave may yield some convection for ASN/ANB by mid/late Wed afternoon, but overall chances are lower on Wed as the overall upper shortwave weakens and pushes EWD. 08 && .FIRE WEATHER... Southwesterly surface and transport winds at 5-10 mph will continue with additional showers and thunderstorms possible through this evening. Temperatures are forecast to increase tomorrow, though with a decrease in overall afternoon convection as the disturbance aloft moves to our southeast. Heat index values likely increase to over 100 degrees during the afternoon. Minimum RH values should remain above ~45%. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 72 93 74 94 71 / 30 30 20 60 50 Anniston 74 94 74 93 73 / 30 30 20 60 50 Birmingham 75 95 77 94 73 / 20 20 20 60 50 Tuscaloosa 76 96 77 96 74 / 10 10 20 50 50 Calera 75 94 76 93 74 / 20 20 20 60 50 Auburn 74 92 75 91 73 / 30 30 20 60 50 Montgomery 76 97 77 97 75 / 30 20 10 60 50 Troy 74 95 75 94 74 / 30 20 10 60 40 && .BMX WATCHES/WARNINGS/ADVISORIES... Heat Advisory from 11 AM to 9 PM CDT Wednesday for the following counties: Bibb...Blount...Fayette...Greene...Hale...Jefferson... Lamar...Marengo...Marion...Perry...Pickens...Sumter... Tuscaloosa...Walker...Winston. && $$
Area Forecast Discussion
National Weather Service Denver/Boulder CO
846 PM MDT Tue Jul 19 2022 .UPDATE... Issued at 843 PM MDT Tue Jul 19 2022 A few decaying thunderstorms over the Front Range at this hour will gradually fizzle out as the evening wears on. After another very warm day (Boulder tied its daily record of 100 F today), temperatures will cool more than previous nights, with lows dropping below 70 degrees for the metro area and closer to 60 F in the plains. No significant changes were made to the forecast this evening, as it looks to be on track. Look to renewed scattered showers and thunderstorms tomorrow after that, similar to Tuesday, will be focused over the southern half of the Front Range, and along/south of I-70. && .SHORT TERM...(This evening through Wednesday) Issued at 303 PM MDT Tue Jul 19 2022 Not much moisture in sight according to the mid level water vapor imagery on GOES-16 as weak showers continue across the Palmer Divide. Tonight, high based showers will dissipate across the region and partly cloudy skies will remain. Temperatures will be slightly cooler overnight compared the yesterday with most of the eastern plains and urban corridor drops to the lower to mid 60s. For the mountains and valleys, temperatures will dip into the mid 40s to lower 50s. Upper level ridge pattern continue through Wednesday afternoon. Heights continue to increase across the GFS/ECMWF as the 500mb high pressure system sits over the Four Corners. Near the surface, a stationary front develops which will drive moisture to the mountains and valleys early Wednesday afternoon. Although, 700mb levels from the HRRR and NAM trend dry with relative humidity percentages near 15-20%. 700mb winds remain fairly weak through Wednesday afternoon near 10-15kts will inhibit thunderstorm flow for the mountains and valleys which may also limit development due to weak shear. In this case, it is likely these thunderstorms will struggle to sustain across the Front Range thus PoPs were slightly decreased across the plains. The flash flood threat for all burn areas remains limited. .LONG TERM...(Wednesday night through Tuesday) Issued at 303 PM MDT Tue Jul 19 2022 Thursday, the upper level ridge shifts eastward resulting in height rises and temperatures warming aloft. Highs will be a couple degrees warmer than Wednesday with highs in the mid to upper 90s for the lower elevations and 60s to 80s for the high country. The airmass will be slightly drier with model soundings exhibiting well-mixed profile with large temperature-dewpoint spreads at the surface in the afternoon. Elevated to near-critical conditions are possible over spotty areas of the plains (See Fire Weather section). With marginal amounts of instability, there will be a low chance for afternoon showers/thunderstorm; however, they are expected to be lower in coverage. The better chances will be over the higher elevations and south of I-70. Friday, a weak trough pushes into the Pacific NW with the ridge aloft building further over Colorado. In response, 700mb temperatures likely rise into the 18-20C range supporting the hottest day of the period. Ensemble guidance shows a good chance for triple digits over the eastern plains and a healthy percentage of members around/near 100 for Denver as well. A Heat Advisory is not out of the question for the northeast corner and possibly the plains. Moisture increases gradually into western Colorado with PW values still around normal northeast Colorado. With marginal amounts of instability, there will be a chance for scattered showers/storms, with better chances over the high terrain and isolated chances for the plains. Confidence in the details of the pattern decrease for the weekend and into early next week. Model solutions vary on the details of a weak shortwave trough moving over the top of the ridge this weekend. Ensemble guidance displays general agreement in the ridge flattening and the return of above-normal moisture by Sunday which will increase shower/storm coverage. Early next week, there is variance in the details of another shortwave while a ridge builds in from the west. Ensemble guidance also hints at a generally "cooler" pattern with highs in the lower 90s (as opposed to upper 90s and low 100s) Sunday through early next week. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 532 PM MDT Tue Jul 19 2022 SCT TS continue to move E with a chance of -TSRA persisting in vcnty of KDEN through ~02Z. TS outflow winds may produce brief gusts 30-35 kts...otherwise anticipate prevailing SW/drainage flow most of the evening and into overnight hrs. SFC boundary looks to arrive 07-09Z with transition to NE winds for area terminals. Expect speeds to become light and somewhat variable Wed AM, although leaning to general N/NW winds albeit under 10 kt. Renewed chance of SHRA or TS Wed PM, mainly 20-00Z, with breezy outflow winds once again. VFR conditions expected to prevail through the TAF period. && .FIRE WEATHER... Issued at 303 PM MDT Tue Jul 19 2022 Thursday, model soundings show well-mixed afternoon profiles with plenty of dry air at the surface to support a dry environment. Min relative humidity values drop into the low to mid teens with the lower values over the plains. This is collocated with peak gusts up to 20-25 mph. This will lead to spotty elevated to near critical conditions for the plains. Confidence isn`t high in the potential for critical fire weather conditions due to the limited coverage and duration although, northern Weld County will see a slightly higher chance. Fire weather conditions may be elevated over portions of the plains Friday afternoon. Moisture increases for the weekend reducing threat for fire weather. && .HYDROLOGY... Issued at 303 PM MDT Tue Jul 19 2022 Scattered showers and thunderstorm coverage remain south of I- 70 and near the Palmer Divide. This storms will produce limited rainfall and wind gusts up to 45 mph. The threat of flash flood through tonight remains limited. Wednesday, there is increasing coverage from thunderstorms and PWATs increase to 0.60-0.80 inches across the region. Therefore, all burn areas will continue in a limited threat for flash flooding. Lower precipitable water values and limited instability will keep coverage of showers and thunderstorms lower Thursday and Friday. This will keep the burn area flash flood threat limited/low. Moisture increases over the weekend resulting in an increased threat for flash flooding over the burn areas. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Rodriguez SHORT TERM...AD LONG TERM...Mensch AVIATION...Rodriguez FIRE WEATHER...Mensch HYDROLOGY...Mensch/AD
Area Forecast Discussion
National Weather Service Burlington VT
946 PM EDT Tue Jul 19 2022 .SYNOPSIS... Isolated thunderstorms will move across Northern New York this evening, these storms may produce strong gusty winds. Heat and humidity will be with us through the next several days, peaking on Wednesday and Thursday when heat index values will reach into the low 90s in many locations. A heat advisory is in effect for the Saint Lawrence and Champlain valleys from noon to 8 pm. Widespread showers and thunderstorms will sweep eastward on Thursday, followed by more chances of showers and thunderstorms over the weekend. && .NEAR TERM /THROUGH WEDNESDAY NIGHT/... As of 943 PM EDT Tuesday...Areal coverage acrs the SLV and western dacks has decreased with the loss of sfc heating and developing areas of CIN. However, RAP analysis still shows pockets of instability with additional threat for isolated shower/storm possible thru early Weds, so have kept schc pops going. Also, did some tweaking to the temps, as BTV is still 80F as of 930 PM, while many values are still holding into the 70s. Have bumped temps up a degree or two, especially urban heat islands of the CPV. Rest of fcst in good shape. Previous discussion follows. Will have isolated thunderstorms move into the Saint Lawrence valley and Northern Adirondacks early this evening, dying down after sunset associated with a secondary cold front pushing into the region. This front will not bring a large air mass change though, and overnight low temperatures will remain quite warm with mins mainly ranging through the 60s. Surface and upper level ridges build over our region overnight. Think that we could see some fog develop as the ground is quite situated after recent heavy rainfall. There remains some question though as the winds aloft could preclude fog formation. With surface and upper level ridging remaining over our region, Wednesday will be quite hot with high temperatures ranging through the 80s into the lower 90s. A heat advisory is in effect for the St Lawrence and Champlain valleys from noon to 8 pm. Heat indices will reach the 95 to 100 range in the afternoon. Will have a slight chance for showers Wed afternoon with surface instability in place, but we may be capped. On Wednesday night aforementioned ridges will slide eastward, and next system which will impact our region mainly on Thursday will approach from the Great Lakes region. Will have chance for showers beginning early Thursday morning in our Northern New York zones. Overnight lows will be even more mild than tonight with lows not making it below 70 in parts of the region, with humid conditions continuing as well. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... As of 343 PM EDT Tuesday...Main concern for Thursday is locally strong to severe thunderstorms, especially during the afternoon and early evening hours. Could be a rather widespread convective event, and will continue to monitor trends carefully. Pre-frontal trough combined with mid-level cyclonic flow/height falls with approaching H7-H5 trough will coincide with peak daytime heating based on 12Z NWP guidance suite. Looking at 850mb theta-e ridge in place across VT with 850mb temps generally +18C to +20C. This should contribute to valley highs near 90F. Boundary layer dewpoints near 70F will contribute to very unstable conditions, with SBCAPE 2000-3000 J/kg and deep layer shear of 30-40kts. Should see widespread convective storms in the afternoon with embedded small scale bows and possible supercells given expected conditions. Agree with SPC Day 3 slight risk, and have included enhanced tstm wording for Thursday afternoon. Have also boosted PoPs to 70-80% during the mid-late aftn. Lastly, should see heat index values 90-95F in advance of convective storms. Trailing cold front approaching from sern Ontario should bring lingering showers along the boundary through the evening hours, followed by clearing later Thursday night. May see some patchy fog development in the favored valley areas after midnight, especially in locations seeing heavier rainfall totals. Lows Thursday night generally in the low-mid 60s. && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 343 PM EDT Tuesday...Cold frontal passage Thursday night will bring somewhat lower humidity levels for Friday and Saturday (dewpoints in the lower 60s). That said, only modest change expected in temperatures with highs 85-90F both Friday and Saturday. Zonal mid-level flow and overall lack of forcing should keep Friday dry, but trend toward slightly cyclonic mid- level flow on Saturday may allow for a few afternoon thunderstorms, especially across the northern half of the forecast area. Included 20-30% PoPs for the afternoon and early evening hours on Saturday. A stronger shortwave trough brings the potential for scattered showers and thunderstorms headed into Sunday afternoon (PoPs 30-40%), with highs in the lower 80s. Following this shortwave trough, may see a trend toward more seasonable temperatures and lower humidity levels headed into Monday-Tuesday next week. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... Through 00Z Thursday...A few decaying thunderstorms are traversing the Adirondacks, and activity should dissipate over the coming hour and with winds quickly trending light and variable. Mainly VFR overnight, with some clouds lingering from the convection, but otherwise, mainly high clouds. There should be enough clearing that some fog should develop, and with recent widespread rain, think we should see some fog even beyond the climatologically favored spots and have mention of it at KSLK, KMSS, KEFK, and KMPV between about 07Z and 12Z. Thereafter, winds increasing to about 5 knots. Cumulus should develop with bases about 5000 to 7000 ft agl after 15Z. Outlook... Wednesday: VFR. NO SIG WX. Wednesday Night: VFR. Chance SHRA, Chance TSRA. Thursday: VFR. Likely SHRA, Chance TSRA. Thursday Night: VFR. Slight chance SHRA. Friday: VFR. Slight chance SHRA, Slight chance TSRA. Friday Night: VFR. Slight chance SHRA, Slight chance TSRA. Saturday: VFR. Slight chance SHRA, Slight chance TSRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...Heat Advisory from noon to 8 PM EDT Wednesday for VTZ001-002- 005-009-011. NY...Heat Advisory from noon to 8 PM EDT Wednesday for NYZ026>028- 035-087. && $$ SYNOPSIS...Neiles NEAR TERM...Neiles/Taber SHORT TERM...Banacos LONG TERM...Banacos AVIATION...Neiles
Area Forecast Discussion
National Weather Service Grand Rapids MI
1121 PM EDT Tue Jul 19 2022 LATEST UPDATE... Update .UPDATE... Issued at 1122 PM EDT Tue Jul 19 2022 I am still thinking the severe storm risk through sunrise is minimal at best. The short story for why is that we are in the right exit region of the polar jet core that is driving this current storm system. As a result, the low level jet speed max is over the upper peninsula of Michigan overnight. That puts our entire CWA in the speed divergence region of the low level jet which in not a good place for severe storms. There is also very dry air above 500 mb which creates a poor environment for storms to develop. There is, however, a chance for rain showers due to the moist air between 850 and 500 mb near and just ahead of the surface cold front. There is decent surface convergence with the front itself and there is some upper divergence over the front between 500 and 300 mb. That will continue until the front gets to the western shore of Lake Michigan towards morning. This results in a line of rain showers, which is shown by both the 00z HRRR and the 00z HREF over central and eastern WI after midnight. That line of showers moves into western lower Michigan just before 8 am Wednesday morning. As I write this, there are developing stronger storms over extreme northwest WI and the extreme western section of the Michigan upper peninsula. Overnight,where SPC has their slight risk, there is the greatest instability. It is that area, if any, that would receive severe storms tonight. The biggest threats being large hail and damaging winds. My spin is there will be a building line of convection ahead of the cold front, that there is already, but that the convection will build father south after midnight. However, due to the dry air above 500 mb, the storms will not be able to grow. That would then limit the convection to just rain showers. There could be enough instability north of Little Sable point for a few thunderstorms. South of Little Sable Point, rain showers are more likely, with locally heavy rain showers possible. The 12 hour QPF from the HRRR has consistently shown less than 0.10 inches south of Muskegon. In fact the 6 hour HREF probability- match mean (PPM) shows nothing over .10 inches through 8 am, south of Traverse City. The ensemble max shows the .10 north of Muskegon as per the HRRR. So the bottom line is, expect isolated thunderstorms with numerous light rain showers west of US-131 and north of Little Sable Point between midnight and sunrise. Between Holland and Muskegon expect scattered light rain showers between 3 am and 8 am. Wednesday, during the day, we see the troposphere fold eastward associated with the upper low moving across Michigan. This effectively pushes the better deep lift east of our area so the stronger storms will be well east of our CWA. && .DISCUSSION...(This evening through next Tuesday) Issued at 216 PM EDT Tue Jul 19 2022 ...Risk for some thunderstorms tonight... Models are generally showing a low level jet moving in from the west after midnight. This feature draws in moisture from the southwest which leads to elevated instability. The region north of a Muskegon to Grand Rapids line has the best potential for storms as they will be closer to the nose of the low level jet and also see the most instability. In addition the arrival of a stronger mid level wave leads to height falls. The best height fall occur north of the CWA. If thunderstorms can get going...damaging winds would be the main risk given the stronger wind fields advertised by the guidance. Deep layer shear is shown to be over 35 knots for northern parts of the CWA...especially after midnight. SPC has this area in a marginal risk for severe thunderstorms. ...Gusty winds for Wednesday Afternoon... The mixing height deepens considerably Wednesday afternoon. At the same time...models are strengthening the winds at the top of this mixed layer. Based on Bufkit overviews...most models show inland areas mixing into the 30 knot range of winds. These winds are also supported by the ensemble guidance. These winds may be enough to generate isolated power outages. The incoming 12z ECMWF is showing gusts around Mount Pleasant and Lansing topping 40 mph by 19z Wed. If this trend of stronger winds continues...we may indeed see some inland wind gusts values approaching advisory criteria for a few hours. The mixing height diurnally decreases in the evening which will support diminishing winds. ...A marginal risk for severe thunderstorms near Lansing and Jackson Wednesday afternoon... A cold front will push eastward through the region late Wednesday morning into the early afternoon hours. It is possible that enough warm and moist air advection could occur to support a few storms to get going. Locations well inland stand the best chance to see isolated/scattered storms. It is worth noting that most models don`t generate convection Wednesday afternoon until the front clears Lansing and Jackson. The NAM and NAM 3km models generally show much higher surface dewpoints compared to the other models Wednesday afternoon...which leads to considerably greater instability. The deep layer shear is supportive for organized if storms do get going...they will need to be monitored closely. ...Thunderstorms possible over the weekend... Models are showing the mid to upper level flow becoming zonal with the thermal gradient tightening up. A stronger upper level jet develops over the Great Lakes Region Saturday into Sunday with some upper level divergence noted. At the same time a 30 to 40 knot low level jet noses into MI...mainly Saturday night...which advects in increasing moisture. All this leads to instability and an increased risk for thunderstorms...perhaps widespread. We will continue the trend of increasing POPs for this period. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 808 PM EDT Tue Jul 19 2022 Overall I am thinking solid VFR through Wednesday. While it is true the surface storm moving through Michigan Wednesday is unseasonable strong (991 mb low) and that will mean strong winds both surface and aloft, the system is seriously moisture staved. It would seem we could see some showers (maybe a thunderstorm) move through the western TAF sites in the 10z to 14z time frame with the cold front, those showers are expected to dissipate once they get east of US-131. Thunderstorms are expected to develop but more likely east of I-75 (Detroit area)late in the day. The biggest impact this system will have on aviation in southwest Michigan is the strong winds. Once the cold front comes through expect winds should sustain 15 to 20 knots with some gusts near 35 knots. && .MARINE... Issued at 216 PM EDT Tue Jul 19 2022 The south to southwest winds will continue to increase this evening into tonight generating higher waves. Areas to the north of Holland will likely see wave heights above 4 feet with values over 6 feet possible Wednesday morning. The hazardous conditions will persist through Wednesday but gradually improve Wednesday night. We will maintain the current swim and boating headlines as a result. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Beach Hazards Statement from 2 AM EDT Wednesday through Wednesday evening for MIZ056-064-071. Beach Hazards Statement through Wednesday evening for MIZ037-043- 050. LM...Small Craft Advisory until 8 PM EDT Wednesday for LMZ847>849. Small Craft Advisory from 2 AM to 8 PM EDT Wednesday for LMZ844>846. && $$ UPDATE...WDM DISCUSSION...MJS AVIATION...WDM MARINE...MJS
Area Forecast Discussion
National Weather Service Huntsville AL
758 PM CDT Tue Jul 19 2022 ...New NEAR TERM... .NEAR TERM... (Tonight) Issued at 758 PM CDT Tue Jul 19 2022 Convective cells continue to develop across north GA but have yet to rematerialize over north AL of middle TN as earlier clouds and morning convection stabilized the atmosphere. Convective instability was rather strong just to our west over the mid South with MLCAPE values 3000-4000 J/kg. This is also where moisture transport is beginning to increase in west TN and north MS. This should continue to increase overnight as the west-southwest LLJ accelerates to 25-35kt. HRRR and the 12Z ARW indicated convection will develop later this evening and overnight in the moisture transport axis over western and middle TN, then drop southeast into southern middle TN and northeast AL. With this in mind, will keep a chance category PoP across southern middle TN and northeast AL. && .SHORT TERM... (Wednesday through Friday) Issued at 312 PM CDT Tue Jul 19 2022 Cloud cover and isolated to scattered showers and thunderstorms should linger near this weakening boundary through the morning hours. This will hopefully keep highs from reaching the 97 to 99 degree range in NW Alabama, given the forecast 925 mb temperatures in some guidance. Still expect highs to climb into the 95 to 97 degree range near and west of the I-65 corridor though. With moisture pooling along that boundary in the morning to early afternoon hours, expect the combination of humidity and air temperatures to push heat index values into the 105 to 109 degree range. Therefore, the Heat Advisory was continued from 11 AM through 6 PM on Wednesday. If temperatures reach the 98 or 99 degree range tomorrow, a excessive heat warning may be needed for portions of northwestern Alabama. Highs don`t look too different on Thursday, as models show more cloud cover ahead of an along a new weakening frontal boundary that moves southward from southern middle Tennessee into northern Alabama. Isolated to scattered showers or storms could occur along it, but not sure forcing will be very good and timing wouldn`t favor a lot of activity given lack of shear. Most guidance pushes this front to near or south of the Tennessee River by noon or so on Thursday. How much redevelopment/coverage will occur along the front into northern Alabama is questionable given the movement of the front. However, some isolated to scattered convection could refire in the afternoon into the early evening hours. Given forecast instability, a stronger storm producing damaging winds cannot be ruled out, but is very uncertain. In addition, pooling of moisture ahead of the front and continued 925 mb temperatures near the front in the 27 C to 29 C degree range could again produce heat index conditions reaching 105 and 109 degrees. However, if highs are cooler than expected due to cloud cover, this may change. A return of much drier air is expected on Friday behind the front. Isolated to widely scattered convection cannot be ruled out south of the Tennessee River. Air temperatures will not be much lower though, still reaching the 95 to 97 degree range near and west of the I-65 corridor. && .LONG TERM... (Friday night through Tuesday) Issued at 312 PM CDT Tue Jul 19 2022 Friday night we expect lows only to drop into the upper 60s to lower 70s under clear skies. Highs in the lower to mid 90s will continue into early next week. The center of the upper ridge will remain more to our west and east through that time, with a weakness in the ridge remaining over the area. This will push heat index values at least close to 105 degrees through that period. && .AVIATION... (00Z TAFS) Issued at 520 PM CDT Tue Jul 19 2022 VFR flight weather conditions are expected during the period with the exception of conditions in and near TSRA. Isolated to scattered TSRA are possible this evening and overnight in southern middle TN and northeast AL, mainly northeast of KHSV. Within these areas, temporary IFR or MVFR conditions are possible. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...Heat Advisory from 11 AM to 6 PM CDT Wednesday for ALZ001>009- 016. TN...Heat Advisory from 11 AM to 6 PM CDT Wednesday for TNZ076-096- 097. && $$ NEAR TERM...17 SHORT TERM....KTW LONG TERM....KTW AVIATION...17
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1048 PM CDT Tue Jul 19 2022 .SHORT TERM... (Through Late Wednesday Night) Issued at 250 PM CDT Tue Jul 19 2022 Latest deterministic and ensemble model guidance keeps upper level ridge axis to our west with trough to our east in the short term. So we will remain in weak northwest flow aloft with a vigorous upper level shortwave over the Northern Plains sliding east southeast through the Great Lakes Region over the next 24 to 36 hours. This will drag an associated cold front through the forecast area. The main energy and moisture will stay well north of the region so it will be a dry frontal passage. Therefore on Wednesday there will be a wide range of temperatures across the region with highs ranging from the upper 80s north to between 100 and 103 across the far south. Dewpoints will remain in the mid 60s to mid 70s through midday tomorrow. Then latest NAM, GFS and RAP forecast soundings are still indicating decent mixing to at least 850mb across central Missouri, as well as the Ozarks during the afternoon hours, so expect the higher dewpoints in this area will lower into the low to mid 60s. However with highs in the mid 90s to near 103, will still see heat index values between 100 and 109 degrees. The highest heat index values will be over Reynolds, Iron and Madison counties topping out between 105 and 109 degrees. So have issued a Heat Advisory for these 3 counties for Wednesday afternoon/early evening. As for low temperatures through the short term, it will remain rather mild tonight with lows in the upper 60s to upper 70s. Then on back side of the cold front, lows Wednesday night will be near normal in the mid 60s to low 70s. Byrd .LONG TERM... (Thursday through Next Tuesday) Issued at 250 PM CDT Tue Jul 19 2022 Even though a surface ridge will build in over the region early on Thursday, little to no CAA associated with it. Therefore highs will still be above normal Thursday. Beyond Thursday, latest WPC cluster analysis continues to indicate good agreement among the ensembles with the upper level ridge building eastward through the weekend. This will usher in a strong southwesterly flow across the region with well above normal temperatures. Some deterministic and ensembles are hinting that the upper ridge will flatten later in the weekend, allowing the first in a possible series of upper level shortwaves to slide east through the Great Lakes region. This would drag a cold front down into Missouri and Illinois with increasing chances of showers and storms, especially by Monday and Tuesday. With the stronger upper level ridge overhead Friday and Saturday, highs will top out between 95 and 105 both days. This extreme heat combined with dewpoints in the 60s to low 70s could create heat index values in excess of 105 at a number of locations, so will need to keep an eye on this trend for possible heat headlines. Still some question as to temperatures and heat index values on Sunday depending on where the front will be. Byrd && .AVIATION... (For the 06z TAFs through 06z Wednesday Night) Issued at 1039 PM CDT Tue Jul 19 2022 VFR conditions will persist through the period. Few/scattered high clouds will pass overhead in the first few hours of the TAF period, which is remnant of a convective feature out of the central plains late Monday night into early Tuesday morning. There is also a brief, but subtle wind shift out of the southeast ahead of this. Given winds are well under 10 knots at most locations, this will have relatively little impact as surface flow quickly returns out of the south. A cold front is currently positioned over interior sections of Iowa and entering northwest Missouri. Other than the veering surface flow, the front will pass through relatively quiet. Maples && .PRELIMINARY POINT TEMPS/POPS... Saint Louis 78 97 72 97 / 0 0 0 0 Quincy 72 88 67 92 / 0 0 0 0 Columbia 74 96 69 100 / 0 0 0 0 Jefferson City 75 98 70 101 / 0 0 0 0 Salem 74 95 69 92 / 0 0 0 0 Farmington 74 100 69 96 / 0 0 0 0 && .LSX WATCHES/WARNINGS/ADVISORIES... MO...IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Marquette MI
736 PM EDT Tue Jul 19 2022 .UPDATE... Issued at 736 PM EDT TUE JUL 19 2022 Convection upstream of Upper Michigan this evening has largely been held in check thanks to some capping in the lower-levels. Rapid refresh models continue to cut back on both timing and coverage through the evening hours, with 22Z HRRR still suggesting some iso tsra across wern Gogebic around 00Z, which seems a little excited given latest sat trends; however, there is some vertical growth beginning to show along a line from Superior to just west of Minong (which lines up somewhat with HRRR if these blips continue to grow). With diurnal heating ending, sfc-based threat of thunderstorms are beginning to look less likely with sfc front back across the MN/WI border. Model soundings do suggest some elevated MUCAPE to work with as temps aloft cool with low pressure moving overhead. That could still bring a marginal hail threat as effective shear remains on the lower end. && .SHORT TERM...(This evening through Wednesday) Issued at 347 PM EDT TUE JUL 19 2022 Severe weather that produced large hail last night tappered off this morning in association with the warm front of an approaching low. A few showers and storms did linger through the day as temperatures mainly reached the 70s, and currently, some showers are moving through eastern Upper Michigan. As a cold front moves in from the west tonight, some hail and strong winds will again be possible. Overnight, 0-6 km bulk shear of around 30 knots and ML CAPE of 1000 to 1500 J/kg is expected. .LONG TERM...(Tonight through Tuesday) Issued at 327 PM EDT TUE JUL 19 2022 Persistent clouds, strong capping, and limited low level forcing have kept convection at bay today. There still appears to be a window for at least a broken line of convection along the surface front as it pushes east this evening. While frontal convergence is unimpressive...cooling aloft as the upper low approaches may be enough to fire some thunderstorms from the Arrowhead of MN into western Lake Superior. If storms fire, there`s still enough wind shear for a few stronger storms. Most hi res guidance shows storms dying off pretty quickly after sunset so confidence isn`t very high as to how far east storms will get. The further south you go the rain chances will be less. Upper low will move right across the U.P. on Wednesday. Expect a few scattered showers to linger through the day over inland areas but they should be mainly light. Drier air moves in later in the day as ridging pushes east. Northwest winds could gust up to 25 knots behind the front over Lake Superior Wednesday night into early Thursday...expect a moderate to high swim risk to exist for Alger County beaches east of Munising overnight Wednesday through about midday Thursday. Beyond Wednesday, it looks like generally tranquil and seasonable weather for late week through the weekend. Weak shortwaves passing just south of the area late Friday and again Saturday afternoon may trigger a couple of showers south, but most will remain dry. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 722 PM EDT TUE JUL 19 2022 An area of low pressure moving across northern MN into Ontario this evening will drag a cold front across Upper Michigan tonight through tomorrow. This will bring gusty southerly winds tonight, that will gradually diminish and veer to the SW tonight and WNW by tomorrow. VFR conditions should prevail through much of the period; however, there is a chance for some MVFR cigs late tonight through tomorrow morning due to abundant low-level moisture. CMX could see some marine fog advect across the terminal tomorrow morning, but confidence is too low to include in TAF at this time. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 327 PM EDT TUE JUL 19 2022 Gusty south winds over the eastern Lake tonight will turn westerly on Wednesday behind a cold front. Expect west and northwesterly winds gusting up to 25 knots from late Wednesday afternoon through the morning hours on Thursday. Beyond that, expect winds less than 20 knots across the Lake through the weekend. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Beach Hazards Statement until 10 PM EDT this evening for MIZ014. Lake Superior... None. Lake Michigan... None. && $$ UPDATE...JAW SHORT TERM...KT LONG TERM...MZ AVIATION...JAW MARINE...MZ