Aikyam-Lab/Synoptic-Bench huggingface dataset:
218 AM MDT Sat Aug 28 2021 MORNING DISCUSSION: Synoptic Setup: Forecast begins with relatively mild weather and weak trough running down Alberta into central Montana. A weak ridge lies over the pacific coastline with a weak trough over the Gulf of Alaska. Today: as the weak trough exits this afternoon enough lift will be available for some light rain showers and isolated garden variety thunder.
The persistent leeside trough across eastern Colorado will result in the continuation of breezy south winds at 15 to 25 mph. Much of the upcoming week will be fairly quiet as high pressure aloft builds back northeast from New Mexico.
(Today and tonight) Still expect slightly cooler afternoon temperatures today as boundary layer moisture increases a bit from the SE.
Expect today to be similar to, albeit not a carbon copy of, yesterday, with afternoon temperatures a degree or two lower and slightly higher coverage of diurnal showers/thunderstorms in the higher terrain areas. A weak front will sag into the area and along with increasing moisture ahead of now-Hurricane Ida will lead to the higher coverage than on surrounding days.
A Heat Advisory is not needed today with slightly cooler heat index values today.
This is consistent with the indications for a weak upper level ridge overhead as well. Saturday, the weakness in the upper ridge is expected to remain overhead. A weak synoptic trough will still linger from a disturbance north of the Great Lakes region.
1046 PM MDT Fri Aug 27 2021 Longer-wave H5 trough remains in place across western Canada, with smaller waves rotating around this trough across then northern tier of states. The trough passing to the north will bring a weak cold front southward this evening, bringing increased humidity. Since timing is earlier than peak heating, shower activity will again be minimal, and mainly limited to the Bighorn Mountains, closest to the trough. Zonal flow will take over on Sunday as the previous trough moves out of the area.
Expect another warm night tonight across the region as the upper level ridge remains in place. As we round out the weekend the upper ridging continues to weaken overhead as a frontal boundary sags into northern Missouri and northern Kansas and stalls out on Sunday.
346 AM CDT Sat Aug 28 2021 The upper trough continues to slowly progress across the northern and central Rockies while ridging has its hold over the eastern CONUS. Heat indices will be around 100 with afternoon temperatures in the low to mid 90s. The HREF has the highest thunderstorm probabilities focused along and northwest of an Abilene to Hiawatha line, so have focused the highest PoPs in this area overnight.
Issued at CDT Fri Aug 27 2021 Late this afternoon, an upper trough was located across the central Rockies. A downstream upper level ridge axis extended from the southeast US north-northwest into the southern Great Lakes. Saturday through Sunday night, The upper level trough across the central Rockies will lift east-northeast across the northern and central Plains. Highs on Saturday will range from the lower to mid 90s with heat indices around 100 degrees. The H5 trough will lift northeast across the Great Lakes States.
Ida is being steered around the lower tropospheric ridge which extends across the southern states and broadens across the east coast, then east southeastward north of the Bahamas. After several rounds of showers and a few thunderstorms earlier this evening, the resulting broad and largely stratiform running from around the Dry Tortugas, across the Lower Keys to the outer Florida Straits off of the Middle Keys has steadily congealed into showers with a few embedded thunderstorms. Have raised pops in the Lower Keys to categorical and kept a high chance in the Upper Keys. Ida continues to move northwestward through the southeastern Gulf of Mexico and around a Ridge extending from north of the Bahamas to the eastern United States.
The moisture combined with a weak upper trough and daytime heating should yield another round of scattered convection this afternoon and evening.
Otherwise, ingested the most recent several hours of temperature and dewpoint data and interpolated through the overnight hours to lows in the low to mid 70s areawide.
456 AM EDT Sat Aug 28 2021 High pressure will gradually move onshore today off the Carolina coast. This high sets up a blocking pattern for most of north GA. Overnight lows will remain around 70 with cooler temps in the mountains.
Hot and humid conditions will remain, with temps right around normal (mid 80s to low 90s) and dew point temps in the low 70s. After making landfall, Ida will begin to move in a northeastward direction, being directed by a developing upper-level trough. Depending on its interaction with this trough will greatly influence our forecast and where the eventual track of the low pressure goes.
High pressure is in control and VFR conditions are expected through the period at all sites. SR Chattanooga Airport, TN 91 73 90 72 89 / 20 10 20 10 30 Knoxville McGhee Tyson Airport, TN 93 71 92 71 91 / 20 10 20 10 30 Oak Ridge, TN 92 71 91 70 90 / 20 10 20 10 30 Tri Cities Airport, TN 92 66 92 67 91 / 10 0 20 10 30.
Meanwhile a cold front will be surging southeast into northwest Nebraska late this afternoon. Steeper mid-level lapse rates will advect eastward across the area this afternoon which will help contribute to around 2000 J/KG MLCAPE near the trough. Appears there should be enough shear through near the trough to support some organized updrafts with the potential for a few strong to severe storms.
The upper trough continues to slowly progress across the northern and central Rockies while ridging has its hold over the eastern CONUS. Heat indices will be around 100 with afternoon temperatures in the low to mid 90s. The HREF has the highest thunderstorm probabilities focused along and northwest of an Abilene to Hiawatha line, so have focused the highest PoPs in this area overnight.
Upper level ridging along with southerly surface winds and relatively high surface dew points will result in heat index values topping out around 100-102 this afternoon. A much better chance for showers/storms can be expected Sunday afternoon as an upper level trough moves eastward through the Northern Plains and Great Lakes regions flattening the upper level ridge and sending a cold front southeastward into northern MO Sunday afternoon.
/Issued 456 AM EDT Sat Aug 28 2021/ High pressure will gradually move onshore today off the Carolina coast. This high sets up a blocking pattern for most of north GA. Overnight lows will remain around 70 with cooler temps in the mountains.
The attendant cold front may provide enough lift for a few showers and weak thunderstorms during the late morning and early afternoon across the MT-WY border, but any precipitation should be light and isolated in nature. With the lower geopotential heights come cooler temperatures, generally running about 5 to 10 degrees below seasonal normals. The CAA east of the Divide keeps relative humidity fairly high, but locations west of the Divide remain slightly warmer and dry: The combination of breezy and dry conditions over portions of southern Wyoming (including Sweetwater county) is expected to cause critical fire weather conditions, and a Red Flag Warning remains in effect here through sunset. Those in the Upper Green River Basin (including Bondurant, Marbleton, and Pinedale) can expect sub-freezing low temperatures.
410 AM CDT Sat Aug 28 2021 Key Points: - Warm and muggy conditions are expected to continue today into tomorrow as a cold front approaches from the northwest. Synoptically, large area of high pressure is anchored just off the east coast of the US, with a trough of low pressure moving across central Canada and a second phased trough developing across the west Central Plains today.
Meanwhile a cold front will be surging southeast into northwest Nebraska late this afternoon. Steeper mid-level lapse rates will advect eastward across the area this afternoon which will help contribue to around 2000 J/KG MLCAPE near the trough. Appears there should be enough shear through near the trough to support some organized updrafts with the potential for a few strong to severe storms.
Expect VFR conditions across the Rio Grande Valley this morning before showers and thunderstorms develop later this morning into the afternoon across the area as a weak 500mb inverted trough across southwest Texas enhances convection along the seabreeze front. /issued 425 AM CDT Sat Aug 28 2021/ SHORT TERM (Today through Sunday): A weak 500mb low/inverted trough across south Texas will provide scattered showers and isolated thunderstorms across deep south Texas this afternoon as the seabreeze front develops across the coastal sections and moves inland today. Swells from Hurricane Ida will begin to reach the lower Texas coast Sunday and this will provide elevated rip currents as well as high surf at area beaches. minor coastal flooding is possible along the lower Texas coast mainly at high tide.
643 AM CDT Sat Aug 28 2021 Key Points: - Warm and muggy conditions are expected to continue today into tomorrow as a cold front approaches from the northwest. Synoptically, large area of high pressure is anchored just off the east coast of the US, with a trough of low pressure moving across central Canada and a second phased trough developing across the west Central Plains today.
/Issued 317 AM CDT Sat Aug 28 2021/ Thunderstorms will again be possible across the western and central Panhandles this afternoon and this evening and a couple may spread into the northeast CWA later on tonight closer to the upper level dynamics from a passing short wave trough moving across the northern plains. On Sunday a cold front should be across the northwest CWA and this will likely become a focus for additional showers and thunderstorms.
524 AM CDT Sat Aug 28 2021 (Today and tonight) Still expect slightly cooler afternoon temperatures today as boundary layer moisture increases a bit from the SE.
Concur with deterministic output that the upper inverted trough will move slowly westward across the CWA today and combine with copious moisture to generate scattered convection.
Sunday will be a much better day as the upper level trough pulls off into east central Canada/Great Lakes region and surface ridging builds into our area. Cooler air behind today's system will bring highs in the mid 70s to lower 80s, along with more comfortable dew points.
SHORT TERM (Today through Sunday): A weak 500mb low/inverted trough across south Texas will provide scattered showers and isolated thunderstorms across deep south Texas this afternoon as the seabreeze front develops across the coastal sections and moves inland today. Swells from Hurricane Ida will begin to reach the lower Texas coast Sunday and this will provide elevated rip currents as well as high surf at area beaches. minor coastal flooding is possible along the lower Texas coast mainly at high tide.
The overall pattern is defined by a weak upper ridge to our north, producing east to southeast steering flow. HREF neighborhood probabilities focus on two favored areas of development--one being over the higher terrain of Graham/Greenlee Counties and the other south to southwest of Tucson along the International Border.
Upper trough is in the process of advecting across the region, with broad ascent and residual instability resulting in a few convective showers over the central FA, while further west a residual FGEN band in is supporting rain showers. Secondary cold front will quickly push south across the region this afternoon, with a period of breezy NW winds expected, esp on the SD plains.
Surface lee troughing in eastern CO has maintained the southerly winds across southwest KS, and this feature will persist through the day Saturday bringing 15-25 mph winds with gusts of 30-35 mph. Temperatures at 16Z across our area were generally in the low to mid 80s, with a few upper 80s near the KS/OK border. Otherwise, afternoon highs will be 5-10 degrees cooler than Saturday for most of southwest KS, as only the far southeast zones miss out on the refreshing cold front.
Southeast winds were slow to decrease along the Lower Keys, but in the past couple hours have decreased to near 20 knots at Sand Key. The forecast will be dominated by the returning influence of the ridge over the southeast U. While drying in the 850-700 mb is expected to reduce rain chances to slight by Sunday, there are interesting mesoscale perturbations as a lower tropospheric high pressure cell over the southeast Bahamas results in a stretched col feature just to the east of the Keys.
A Heat Advisory is not needed today with slightly cooler heat index values today. The Ozarks region remains on the western periphery of an upper level ridge.
An upper trough will move across northern Wisconsin tonight and Sunday. Ahead of it, the low level jet will ramp up again across west-central wisconsin. The low level jet exits mid day Sunday and there is little other forcing, but there may be some surface convergence to kick off some storms as surface winds shift from southwest to westerly as high pressure builds across the northern plains. Temperatures will be somewhat cooler. This will bring quiet weather, lower humidity, and somewhat cooler temperatures.
(This afternoon through Sunday night) A cumulus field is developing across much of the area and a few of these clouds may intensify into thunderstorms over the next few hours in the higher elevations west of the Pecos River.
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.
Upper low will pull out and continue to prolong rain chances across the southern valley into the overnight.
Early Sunday morning a mid-level trough will pass through the central and northern U.
Currently, at 20Z, a broad area of high pressure is in control over the mid-Atlantic region with a broad ridge into the New England region. A Pacific trough continues to translate into the northern Plains with a cold front stretched across northern NE into MN. With return flow from the Gulf into the area around the Bermuda high over the east coast and a lee trough along the front range of the Rockies, winds have been able to gust up into the 20mph range this afternoon across much of the area. With temperatures in the low to middle 90s across the area, heat index values remain in the upper 90s to around 100 degrees this afternoon. The cold pool strength of the storms appears to be the main question as again shear drops off drastically with southward extent from the upper level trough.
SHORT TERM (Now through Sunday Night): A weak 500mb low/inverted trough over the CWA, ample moisture in place, and the seabreeze will continue to support some convection through early this evening. However, large swells directed towards the lower Texas coast from Ida will provide elevated rip currents, possibly high surf, and minor coastal flooding at high tide Sunday into Sunday night. High pressure over northeast Mexico and subsidence from Ida will result in generally hotter and drier conditions on Sunday.
For high temperatures, will go just a bit cooler given possibility of increased clouds.
Small Craft Advisories will remain in effect through the afternoon from the west end of Seven Mile Bridge westward.
Hurricane Ida is currently moving northwest through the central Gulf and will continue along the western periphery of the ridge, likely making landfall as a major hurricane in south-central or southeastern Louisiana Sunday evening/night.
Currently there is Cu building over the higher elevations with lingering moisture and daytime heating. This will improve through the day but leave high temperatures up to 10 degrees cooler than today. This will help to stabilize much of the plains with the cooler temperatures making it difficult to reach convective highs, however there continues to be a slight chance over portions of Park county and east by the late afternoon with brief rain and gusty winds possible.
At upper levels, there is a weak area of troughing across the Northern Plains. At the sfc, low pressure resides over eastern Colorado to eastern SD. Connecting the lows is a cold front, which will be dragged through Nebraska this afternoon and evening. Subsidence from the high will allow for mostly clear skies and highs in the 80s across the region.
Region will be between weak high pressure to the northeast and IDA to the southwest then west this period.
202 PM CDT Sat Aug 28 2021 High pressure continues to dominate the weather across Middle Tennessee both at the surface and aloft.
Going forward into the day tomorrow, will watch the position of the cold front closely.
250 PM CDT Sat Aug 28 2021 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.
PREVIOUS DISCUSSION: Synoptic Setup: Forecast begins with relatively mild weather and weak trough running down Alberta into central Montana. A weak ridge lies over the pacific coastline with a weak trough over the Gulf of Alaska. Today: as the weak trough exits this afternoon enough lift will be available for some light rain showers and isolated garden variety thunder.
A low amplitude upper ridge crossing the Intermountain NW today will relax flow aloft.
Temperatures Sunday should taper back another degree or two with the increase in clouds and showers, especially cooler in the southwest Panhandle.
Surface lee troughing in eastern CO has maintained the southerly winds across southwest KS, and this feature will persist through the day Saturday bringing 15-25 mph winds with gusts of 30-35 mph. Temperatures at 16Z across our area were generally in the low to mid 80s, with a few upper 80s near the KS/OK border. Otherwise, afternoon highs will be 5-10 degrees cooler than Saturday for most of southwest KS, as only the far southeast zones miss out on the refreshing cold front. Much of the upcoming week will be fairly quiet as high pressure aloft builds back northeast from New Mexico.
245 PM CDT Sat Aug 28 2021 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.
Upper trof will continue to move into the Dakotas through this evening.
1225 PM CDT Sat Aug 28 2021 Key Points: - Warm and muggy conditions are expected to continue today into tomorrow as a cold front approaches from the northwest. Synoptically, large area of high pressure is anchored just off the east coast of the US, with a trough of low pressure moving across central Canada and a second phased trough developing across the west Central Plains today.
As of 3 PM CDT, temperatures across the Mid-South are predominantly in the lower 90s at most locations. GFS QPF appeared overdone for the overnight period, given limited nocturnal instability under the pre-Ida upper level ridging. Expect scattered showers and isolated thunderstorms to develop with surface heating on Sunday, as the upper ridge axis lifts north of the area.
Diegan Chattanooga Airport, TN 73 90 72 89 72 / 10 20 10 30 30 Knoxville McGhee Tyson Airport, TN 71 92 71 91 71 / 10 20 10 30 20 Oak Ridge, TN 71 91 70 90 71 / 10 20 10 30 20 Tri Cities Airport, TN 66 92 67 91 68 / 0 20 10 30 20.
Main upper trough is located over eastern MT/WY, with a lead wave moving east through southwest SD. Increasing deep layer shear with the approaching trough will be largely post-frontal, though will be locally enhanced near the boundaries. Sunday should be a much nicer day all around, with modest northwest flow bringing in cooler and drier air.
Also lowered high temperatures today due to cloud cover, topping out in the low to mid 90s.
The current thinking is that the main area of convection with this low level jet stays north of the CWA. If the low level jet sets up further south. On Sunday the cold front pushes through from the northwest.
643 PM CDT Sat Aug 28 2021 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.
Watch for isolated strong to near severe thunderstorms in and amongst the garden variety pulse storms, with some organized outflow pushing toward the lower deserts.
813 PM MDT Sat Aug 28 2021 Another surge/weak cold front will drop south across northeast Colorado later this evening. Confidence in this is not high, so will keep PoPs on the low side. Highs will be about 5-10F cooler Sunday with lower to mid 80s across northeast Colorado. Currently there is Cu building over the higher elevations with lingering moisture and daytime heating. This will improve through the day but leave high temperatures up to 10 degrees cooler than today. This will help to stabilize much of the plains with the cooler temperatures making it difficult to reach convective highs, however there continues to be a slight chance over portions of Park county and east by the late afternoon with brief rain and gusty winds possible.
/issued 237 PM CDT Sat Aug 28 2021/ SHORT TERM (Now through Sunday Night): A weak 500mb low/inverted trough over the CWA, ample moisture in place, and the seabreeze will continue to support some convection through early this evening. However, large swells directed towards the lower Texas coast from Ida will provide elevated rip currents, possibly high surf, and minor coastal flooding at high tide Sunday into Sunday night. High pressure over northeast Mexico and subsidence from Ida will result in generally hotter and drier conditions on Sunday.
As Ida move further away, Atlantic ridging has filled in. The increasing ridging and some lower level drier air moving in from the east will result in a quieter overnight period. Ridging building behind the far away Hurricane Ida will maintain gentle to moderate east to southeast breezes across Keys waters.
High pressure continues to dominate the weather across Middle Tennessee both at the surface and aloft.
Drier air is forecast to continue to move into east-central Florida through the end of the weekend as high pressure over the western Atlantic edges southwest towards the Florida coast. High temperatures will reach the low-to-mid 90s with the warmest temperatures forecast across the interior. High pressure remains stationed over the western Atlc just off of the mid Atlc states dropping slowly south to off of the Carolinas by late Sun.