Aikyam-Lab/Synoptic-Bench huggingface dataset:
/Issued 306 PM EDT Sat Aug 28 2021/ As Hurricane Ida churns to our southwest in the Gulf, high pressure will be situated over the local forecast area helping to limit pop coverage across portions of far northern and eastern Georgia. Still, with a weak impulse traveling around the periphery of the high, have included chances for showers and thunderstorms across mainly central Georgia for this afternoon and evening. For Sunday, chances for rain will remain fairly limited again as high pressure becomes more centered across the forecast area.
Time-lagged HRRR runs capture that activity -- which is immediately ahead of a middle- and upper-level trough axis that's advancing eastward -- well and served as the basis for near-term PoPs. Current surface analysis places low over western Manitoba, with frontal boundary dropping down into western Minnesota and secondary trough in its wake. Upper level analysis places trough sliding over the northern plains. For the rest of this afternoon into tonight, expect showers with some thunderstorms to continue developing over the area with the upper trough gradually working towards the east. This is where the higher instability is located over our area, though this is a bit marginal. Shower and thunderstorms will come to an end from west to east overnight as the trough moves east, with skies clearing in its wake.
629 PM CDT Sat Aug 28 2021 Scattered showers and weak isolated thunderstorms continue over our CWA, with increasing trends in shower coverage as the main mid/upper trough shifts east. Highest instability is still offset behind a cold front that currently extends from near Roseau southeast of Grand Forks and into southeast ND. Upper low will pull out and continue to prolong rain chances across the southern valley into the overnight.
High pressure will bring quieter conditions to start the week before rain chances return for the latter half of the week. Low pressure was located over southeastern South Dakota early this afternoon with a warm front extending northeastward through central Minnesota into northern Wisconsin and Upper Michigan. Once this complex clears the CWA by mid to late this afternoon, an additional round of showers and storms is expected to develop ahead of an eastward moving cold front currently located from eastern North Dakota into central South Dakota.
During this period, our region quickly goes from being to the north of Ida to being located in the northeast quadrant of the storm and this will increase the low level vertical wind shear locally, thus promoting the development of potentially deep mesoscyclones with tornadoes on Sunday. Of course the higher rainfall amounts will be across coastal Alabama, southeast MS and western portions of inland SW Alabama.
As a weak cold front moves through the region later this morning chances for precipitation will diminish.
VFR conditions expected through the period at all sites as high pressure remains in control. SR Chattanooga Airport, TN 92 72 89 71 79 / 10 10 40 40 80 Knoxville McGhee Tyson Airport, TN 92 71 91 71 84 / 10 10 30 30 60 Oak Ridge, TN 92 70 90 71 81 / 20 10 40 30 60 Tri Cities Airport, TN 92 68 91 68 87 / 20 10 30 20 40.
125 AM MDT Sun Aug 29 2021 An upper trough over the northern plains continues to push eastward, with zonal flow/weak ridging behind.
A cold front is expected to move through the GUY and DHT TAF sites by mid morning switching the winds around to the northwest. Going forward into the day tomorrow, will watch the position of the cold front closely.
Guidance has the vast majority of convection dissipating by 18Z with the surface cold front stalling over the area and becoming more diffuse this afternoon. Also have forecast highs near 90 along I-70 and south with slightly cooler temperatures to the north.
Afternoon highs today will run 7 to 10 degrees higher than Saturday however so it will be a bit warmer, but more seasonal.
316 AM CDT Sun Aug 29 2021 An upper level trough will continue to move east out of the northern Plains into the Great Lakes region today, remaining well north of the area. Highs will warm into the upper 80s to the lower 90s with heat index values as high as the middle 90s. An upper level ridge will build to the west of the region early this week leaving the area in an upper level northwest flow pattern.
with a more easterly flow noted at the lower levels.
Associated cold front will push across the area today. As the cold front crosses the area from west to east rain chances will diminish through the day. The biggest story will be the tightening pressure gradient as the low intensifies just north of Lake Superior. The isallobaric component to the wind and best pressure rises along the cold front will be oriented sw to ne into Ontario along the fcst track of the low. Temperatures today will range from the lower 70s west to the lower 80s east with the later timing of the cold fropa.
442 AM EDT Sun Aug 29 2021 Mean layer ridging centered near the Carolinas is driving Major Hurricane Ida to the northwest towards the Louisiana coastline. At 00Z and 06Z, the KKEY RAOB sampled rising heights at most levels as Ida pulls away from the Keys and ridging builds in from the east. Temperatures across the island chain are in the lower to mid 80s with dewpoints in the mid 70s. Isolated showers have managed to form along maritime cumulus rolls, despite the unfavorable thermodynamics in the lower troposphere.
As of 2 am a weak slow moving surface cold front had moved through GLD and NRN with convection appearing to struggle to develop much farther south than the KS/NE state line at that time. The front begins to lift northward into Nebraska as a warm front. Overall model consensus for temperatures in the low 60s over the higher terrain of the west, to more mild low 70s from Stafford to Coldwater/Medicine Lodge.
352 AM CDT Sun Aug 29 2021 A weak cold front is currently pushing toward the I-35 corridor early this morning putting an end to the active and wet weather pattern of the past 3 to 5 days. Highs will generally be in the lower to upper 70s which is right around average for this time of year.
436 AM EDT Sun Aug 29 2021 CWA remains largely dominated by the upper ridge centered across SC, which should keep the eastern majority of the area dry today.
Lows in the low to mid 70z can be expected areawide, with afternoon highs in the upper 80s to low/mid 90s tomorrow. The cooler high temperatures will be seen in our southeasternmost parishes, where cloud cover and rainfall will resume earliest and persist through the remainder of the afternoon.
The Ozarks remains on the western edge of an upper level ridge and under the influence of southwesterly upper level flow. The dry and warm weather will continue through tonight as a cold front makes its way south across the northern and central plains. For Sunday, southerly surface winds will allow low level moisture to continue to filter into the area as the cold front approaches the region through the morning.
340 AM CDT Sun Aug 29 2021 A cold front from near TAD to just south of GLD is expected to stall out from near a DHT to GUY line by this afternoon. Model soundings show that the low levels become unstable by noon especially along and out in front of these features.
237 AM MDT Sun Aug 29 2021 MORNING DISCUSSION: Synoptic Setup: Forecast begins with relatively mild weather and a weak ridge over the PACNW. A closed low has moved onshore over northern British Columbia.
229 AM MDT Sun Aug 29 2021 A low amplitude ridge will take over behind yesterdays upper trough leading to a dry warming trend to start the work week.
Cooler air will filter into the region today, with highs topping out in the low to mid 80s. Last night's cold front will eventually stall to the south of the forecast area. Another round of showers and storms may develop overnight as the low level jet ramps up along the boundary.
Closer to home high pressure just offshore the southeast U. This moist and unstable airmass will support scattered to numerous showers and storms developing during the afternoon with a deep layered southeast wind flow between the high to the northeast and Ida to the northwest pushing the convection toward the northwest around 15 mph during the afternoon, with the highest rain chances and convective coverage focusing along and to the west of the I-75 corridor during the late afternoon and evening hours, which is in line with the latest HRRR guidance.
427 AM CDT Sun Aug 29 2021 An upper level trough was centered over eastern ND and northwestern MN with upper level ridging over the Mid-Atlantic region. Nocturnal convection was across parts of eastern Nebraska and Iowa early this morning, ahead of the upper level trough and associated cold front. A better chance of rain can be expected on Monday, especially in the afternoon, and particularly across southeast MO and southwest IL along and just ahead of the weakening cold front as it drops southward into central MO and southern IL. High temperatures will be cooler on Monday, mainly due to cloud cover, a better coverage of showers/storms, and weak cold air advection behind the cold front across northeast MO and west central IL.
At the upper levels, the base of a longwave trough will continue to move east of the area this morning. Low amplitude ridging will make nudge way in through the day today, bringing with it a mostly sunny sky and high temperatures mainly in the 70s. A few sites across the southwest and south central could reach into the lower 80s. As a weak wave moves through the flow, the ridge tries to flatten a bit but remains in place on Monday. Otherwise, expect a slightly warmer day on Monday with a partly cloudy to mostly sunny sky.
Otherwise, drier and cooler air will move into the area after frontal passage and with the approaching high pressure system. High temperatures are forecast to range from the mid 70s central/north-central to the low 80s east-central and far northeast. This will lead to much quieter conditions along with near normal temperatures for this time of year as slight troughing and west-northwest flow lingers aloft.
As the low-level moisture returns northward into the area in the form of a warm front, it is unclear where exactly this boundary will set up if the elevated convection lingers. NAM model would suggest that the warm front by late afternoon will reside from near Broken Bow to Valentine. By mid-week upper level high pressure builds across the Southern Plains with a deep trough developing across western Canada into the northern Rockies.
558 AM CDT Sun Aug 29 2021 An upper level trough was centered over eastern ND and northwestern MN with upper level ridging over the Mid-Atlantic region. Nocturnal convection was across parts of eastern Nebraska and Iowa early this morning, ahead of the upper level trough and associated cold front. A better chance of rain can be expected on Monday, especially in the afternoon, and particularly across southeast MO and southwest IL along and just ahead of the weakening cold front as it drops southward into central MO and southern IL. High temperatures will be cooler on Monday, mainly due to cloud cover, a better coverage of showers/storms, and weak cold air advection behind the cold front across northeast MO and west central IL.
412 AM CDT Sun Aug 29 2021 A nearly vertically stacked ridge of high pressure will be bisecting the WFO PAH forecast area from west to west, gradually arcing back into the southeast U. By Monday, enhanced shearing aloft near the base of the faster westerlies to the north, combined with substantially increased moisture advection pulled northward by Ida and a deformation zone near the shear axis of the ridge well to the northwest of Ida over Missouri/Illinois/Indiana will help generate greater coverage of precipitation across the WFO PAH forecast area.
Unfortunately, precipitation chances increase once again on Monday and Monday night as a low level warm front over the Central Plains begins to lift northward closer to our area.
The slim rain chances will decrease further through the middle of the week and temperatures will rise as ridging amplifies over the southern Rockies and High Plains.
With long period swells reaching the far offshore waters of the lower Texas coast this afternoon and the nearshore waters tonight. the risk of rip currents will increase during the afternoon into the evening and a rip current statement for high risk of rip currents will likely be needed tonight into Monday as well as a high surf advisory for the lower Texas coast. A coastal flood statement will likely be needed for the lower Texas coast tonight if a coastal flood advisory is not issued.
A cold front is expected to move through the DHT and GUY TAF sites later this morning. The cold front is not expected to quite get to AMA, so southerly winds will prevail there. /Issued 340 AM CDT Sun Aug 29 2021/ A cold front from near TAD to just south of GLD is expected to stall out from near a DHT to GUY line by this afternoon. Model soundings show that the low levels become unstable by noon especially along and out in front of these features. On Monday, there is a weak short wave trough that moves south southeast across the southern Texas Panhandle in the afternoon.
We should warm up today into the low 90s once again.
With dew points in the low 70s, heat indices are expected to approach the mid 90s. Tonight, slow moving cold front is expected to stall near the Iowa/Missouri border.
408 AM MDT Sun Aug 29 2021 Suppressed ridge over the Four Corners and weak troughing along the PACNW Coast will bring somewhat zonal flow over the next 36 hours.
334 AM PDT Sun Aug 29 2021 Hot and very dry today and Monday turning cooler through the rest of the week. Flat ridge pattern over Northern California will begin to erode as upper trough starts to form off the West Coast this afternoon. Ensembles and clusters indicate that the trough will gradually deepen into mid-week. However, the deepening trough will enhance southwest ridgetop winds and could bring critical fire weather conditions to ongoing wildfires. West to southwest wind gusts of 20 to 35 mph, strongest over the higher elevations with minimum humidity of 8 to 25 percent and moderate to poor overnight recoveries are expected.
The path of the storm conts to work arnd the Wrn periphery of an upper lvl ridge, centered along the SE U.
625 AM CDT Sun Aug 29 2021 A nearly vertically stacked ridge of high pressure will be bisecting the WFO PAH forecast area from west to west, gradually arcing back into the southeast U. By Monday, enhanced shearing aloft near the base of the faster westerlies to the north, combined with substantially increased moisture advection pulled northward by Ida and a deformation zone near the shear axis of the ridge well to the northwest of Ida over Missouri/Illinois/Indiana will help generate greater coverage of precipitation across the WFO PAH forecast area.
342 AM MDT Sun Aug 29 2021 An upper trough over the northern plains continues to push eastward, with zonal flow/weak ridging behind. Chances for storms return early Monday morning across south central SD, with positive theta-e advection via the low-level jet increasing after midnight.
(Today through Monday afternoon) An upper level trough is over the Upper Midwest/Northern Plains. Upper ridging is over much of the southern half of the country with Hurricane Ida about to hit the Louisiana coast. The upper trough to the north will lift northward into Canada later today. Chances of showers and thunderstorms will be across most of the area today, and temperatures are expected to be a degree or two cooler than yesterday.
Upper level ridging will build into the area for the middle to latter part of the week, bringing warmer temperatures and largely dry conditions back into the region.
High pressure continues today with another pleasant day in store for the Northern Rockies.
Look for a warmer afternoon today with dry conditions continuing.
Later in the afternoon, a lee surface cyclone is also expected to spin up over the eastern plains, closer to the CO-KS border, which could spark enough low-level convergence to initiate a thunderstorm capable of some small hail and gusty winds. Thanks to the front and lingering clouds, high temperatures today will be a fair bit cooler than the last several days, with low-mid 80s over the eastern plains and mountains valleys. Low temperatures will be in the high-50s to low-60s over the plains, and low-40s over the higher terrain.
/Issued 436 AM EDT Sun Aug 29 2021/ CWA remains largely dominated by the upper ridge centered across SC, which should keep the eastern majority of the area dry today.
624 AM CDT Sun Aug 29 2021 A weak cold front is currently pushing toward the I-35 corridor early this morning putting an end to the active and wet weather pattern of the past 3 to 5 days. Highs will generally be in the lower to upper 70s which is right around average for this time of year.
1020 AM EDT Sun Aug 29 2021 Deep ridging remains in place over the Carolinas today. Moderate breezes over the far western Straits and offshore Gulf waters west of Key West will diminish this afternoon and tonight as high pressure settles across the Florida Keys.
1120 AM MDT Sun Aug 29 2021 Suppressed ridge over the Four Corners and weak troughing along the PACNW Coast will bring somewhat zonal flow over the next 36 hours.
SREF plumes are forecasting the lower shear and CAPE environment to continue into max heating this afternoon.
Cliff PREVIOUS DISCUSSION: Synoptic Setup: Forecast begins with relatively mild weather and a weak ridge over the PACNW. A closed low has moved onshore over northern British Columbia. Today through Monday: A slow warm up is in store as the ridge to the west moves across Montana.
A nearly vertically stacked ridge of high pressure will be bisecting the WFO PAH forecast area from west to west, gradually arcing back into the southeast U. By Monday, enhanced shearing aloft near the base of the faster westerlies to the north, combined with substantially increased moisture advection pulled northward by Ida and a deformation zone near the shear axis of the ridge well to the northwest of Ida over Missouri/Illinois/Indiana will help generate greater coverage of precipitation across the WFO PAH forecast area.
Lows tonight will be mild in the lower to middle 70s.
A quasi-zonal flow pattern aloft is in place across the CONUS, with just a weak trough near the Great Lakes and a slight ridge across the southeast.
We should see one of the warmer days of late, with highs in the mid 80s to lower 90s in the lower elevations.
1235 PM CDT Sun Aug 29 2021 An upper level trough will continue to move east out of the northern Plains into the Great Lakes region today, remaining well north of the area. Highs will warm into the upper 80s to the lower 90s with heat index values as high as the middle 90s. An upper level ridge will build to the west of the region early this week leaving the area in an upper level northwest flow pattern.
High temperatures will be around 10 degrees warmer than yesterday.
/Issued 754 AM EDT Sun Aug 29 2021/ CWA remains largely dominated by the upper ridge centered across SC, which should keep the eastern majority of the area dry today.
Heat and smoke will continue to be the main issue today and tomorrow for most of the area as high pressure remains. However, that ridge will lose its grip on the West Coast over the next 48 hours allowing for a trough to dig across the Western States.
Temperatures not terribly different Monday, perhaps a degree warmer here or there, and winds again remain light. As high pressure amplifies over the Southern Plains states and expands east filling in behind Ida, we'll see some Gulf moisture return the second of this week.
Cooler and unsettled conditions return for the remainder of the work week. Quiet weather conditions continue into Monday as weak high pressure remains over the region.
1126 AM MDT Sun Aug 29 2021 An upper trough over the northern plains continues to push eastward, with zonal flow/weak ridging behind. Chances for storms return early Monday morning across south central SD, with positive theta-e advection via the low-level jet increasing after midnight.
The low level jet develops showers and thunderstorms over the Edwards Plateau and western Hill Country overnight into early morning.
Tomorrow the ridge over the area starts to break down and southwest flow sets up over the region again.
Slight chances of showers and thunderstorms are possible this afternoon again mainly along the higher terrain areas. Otherwise, VFR through the period at all sites as high pressure is in control. SR Chattanooga Airport, TN 90 72 88 71 78 / 20 10 30 50 90 Knoxville McGhee Tyson Airport, TN 93 71 90 71 80 / 20 10 20 30 90 Oak Ridge, TN 91 70 89 70 78 / 20 10 20 30 90 Tri Cities Airport, TN 91 69 88 68 82 / 10 10 20 10 50.
Conditions will remain dry ahead of the main cold front which can be see in visible satellite imagery working its way across the western half of the CWA. Clear skies and post cold front conditions will allow for temps to fall into the mid to upper 50s inland with areas near and along the lake front staying a bit warmer in the low 60s.
A pretty nice morning, all things considered, is ongoing with temperatures generally in the lower to mid 80s across the area. Upper level ridging will build into the area for the middle to latter part of the week, bringing warmer temperatures and largely dry conditions back into the region.
Slight chances of showers and thunderstorms are possible this afternoon again mainly along the higher terrain areas. Diegan Chattanooga Airport, TN 72 88 71 78 70 / 10 30 50 90 80 Knoxville McGhee Tyson Airport, TN 71 90 71 80 70 / 10 20 30 90 80 Oak Ridge, TN 70 89 70 78 68 / 10 20 30 90 90 Tri Cities Airport, TN 69 88 68 82 68 / 10 20 10 50 80.
As Ida continues to move slowly inland through the forecast, the lower conditions in the rainbands of Ida will spread north along and west of a Wilcox to Santa Rosa county line.
After Monday, the rest of the week looks dry as an upper ridge builds over the area.
12Z MAV/MET was a bit more optimistic, but preferred the earlier run with recent rains, cooler temperatures, and radiational cooling (although it may be delayed as the more broken cu field lingers further into the evening).
304 PM EDT Sun Aug 29 2021 Isolated showers were noted earlier today in the Straits, otherwise it has been a dry, warm day in the Florida Keys with sunshine filtered through the high cirrus spilling southeast and southward from Ida. The trough will amplify somewhat as high pressure rebuilds at a lower latitude east of the Bahamas. Local winds will be more influenced over the induced troughing over the Florida peninsula each afternoon and evening.
213 PM CDT Sun Aug 29 2021 What a welcome change as passing upper trough is finally driving frontal boundary through the area scouring out moisture and ending heavy rain threat. Cooler and drier air advecting in with west winds which should gradually diminish tonight leading to a quiet night overall. West to northwest upper flow remains in place to start the new week as ridging starts to occur over north central CONUS.
1257 PM CDT Sun Aug 29 2021 A weak cold front is currently pushing toward the I-35 corridor early this morning putting an end to the active and wet weather pattern of the past 3 to 5 days. Highs will generally be in the lower to upper 70s which is right around average for this time of year.
252 PM CDT Sun Aug 29 2021 Current surface analysis places high pressure over northern Wyoming into Montana, with low pushing over Ontario, keeping a west to northwest breeze over much of our area. Upper level analysis places trough sliding into the Great Lakes region, with rather zonal flow to our west.