Aikyam-Lab/Synoptic-Bench huggingface dataset:
Weak cold front continued to make slow progress southward and at mid afternoon was nearing the I-80 corridor but stalling soon. Dewpoints to the north were in the lower 50s but to the south of the front they were in the lower 70s. Then the main show is later in the afternoon and evening as a digging trough provides large scale ascent. This combined with an approaching strong cold front, strong sfc-3km shear, SBCAPE to around 4000 J/kg and rich moisture in the warm sector. Key messages: 1) Much cooler and very comfortable humidity early in the week. Sunday night: Strong cold front sweeps through the cwa overnight ending the storms, then ushering cooler/much drier airmass into the area. Lows will range from the mid 50s nw to the lower 60s se.
The new week starts off hot and dry as the persistent ridging continues a westward shift. A break from the heat may come mid- week when a trough tries to nudge the ridge out of our region.
515 PM MDT Sat Jun 19 2021 00Z TAF CYCLE Upper high center has shifted over central AZ where it will remain for the next 24 hrs with steering flow from west to east or northwest to southeast.
Meanwhile, tropical depression Claudette was across the MS/AL area with an upper level low to its west over eastern TX. At the sfc a ridge of high pressure extended from the South Carolina and GA into the southern Appalachians with the sfc center of Claudette over west central AL. Further north and northwest, a sfc frontal/baroclinic zone extends from low pressure over the St Lawrence Valley into the northeast and eastern to southern Great Lakes to the central Plains. An associated cold front will begin to approach the lower OH Valley late in the period.
/Issued 209 PM CDT Sat Jun 19 2021/ An area of high pressure in the desert southwest has weakened some and is now centered over the White Mountains of Arizona. A strengthening upper high over southern Arizona and northern Mexico will cause height rises in the area ahead of an approaching cold front on Sunday. Recent high resolution and deterministic model runs suggest that the cold front should advance as far southeast as a line from Dalhart to Guymon, though the cooler airmass will still hang back in Colorado and Kansas Sunday afternoon.
A few showers are popping up this afternoon ahead of a weak warm front and upper level divergence ahead of the tropical low. For the most part, models keep the low to our south, along with most of the rain, but the south and east may see some isolated to scattered showers and storms this weekend, especially during the afternoon hours.
LLWS expected to develop later tonight for the northeast OK sites as the low-level jet strengthens. /Issued 311 PM CDT Sat Jun 19 2021/ One more hot and humid day is in store Sunday before much cooler.
927 PM EDT Sat Jun 19 2021 A series of upper-level disturbances will pass through the region overnight and Sunday while high pressure builds over the Atlantic.
307 PM MDT Sat Jun 19 2021 A Canadian cold front passes southeastward through the area, today, favoring widespread rainfall from tonight through tomorrow. Behind this front expect north northwesterly winds and some much cooler temperatures.
Sunday, a cold front is expected to move southeast across the area during the morning to early afternoon. A few weak disturbances are expected to move across the High Plains behind the front, which will boost precipitation chances for the late afternoon and evening hours. Temperatures will be slightly cooler tomorrow, thanks to the cold front, with highs in the 80s to lower 90s and lows in the 50s. on the eastern periphery of an upper level ridge over the Rockies and Intermountain West. Flow aloft will back to the west by mid-week as the ridge shifts ESE to the Southern Plains. as an upper level low stalls invof the central Pacific Coast. as heights rise in assoc/w the ridge progressing from the Rockies to the Southern Plains. A cold front brings gusty north winds to both sites by mid morning Sunday.
As a result deep layer ridging begins to build over roughly the southern half of the state with the prevailing flow becoming south to southwest. By midweek the high pressure lifts into northern Fl.
508 PM CDT Sat Jun 19 2021 A mainly dry and short lived period over the next 12 hours as weak subsidence on the back end of Claudette along with upper level ridging over the mid south takes place. Troughing convergence over the SE from Claudette and an extending frontal boundary will lift slowly northward on Sunday AM into the coastal waters.
Sunday, a cold front is expected to move southeast across the area during the morning to early afternoon. A few weak disturbances are expected to move across the High Plains behind the front, which will boost precipitation chances for the late afternoon and evening hours. Temperatures will be slightly cooler tomorrow, thanks to the cold front, with highs in the 80s to lower 90s and lows in the 50s. on the eastern periphery of an upper level ridge over the Rockies and Intermountain West. Flow aloft will back to the west by mid-week as the ridge shifts ESE to the Southern Plains. as an upper level low stalls invof the central Pacific Coast. as heights rise in assoc/w the ridge progressing from the Rockies to the Southern Plains.
/issued 508 PM CDT Sat Jun 19 2021/ A mainly dry and short lived period over the next 12 hours as weak subsidence on the back end of Claudette along with upper level ridging over the mid south takes place. Troughing convergence over the SE from Claudette and an extending frontal boundary will lift slowly northward on Sunday AM into the coastal waters.
It will be mostly sunny and fairly dry by in the afternoon, but the models show isolated coverage developing along the Cheyenne Ridge, Front Range Foothills and Palmer Divide after 21z.
A cold front will cross the area late this afternoon and cause winds to turn northerly. Northerly winds will bring in noticeably cooler and more moist air to the area tonight. The higher amounts are expected in the foothills because of the low-level flow and thermodynamic profile working to produce upslope enhancement there.
Regardless, still expecting to see an increasing low level jet and better forcing as the upper level trough approaches. Low clouds and cooler temperatures can be expected behind the storm system on Sunday. A somewhat amplified upper trof will exist over the eastern CONUS early in the period. At that time a mid-level thermal ridge will again expand across the Northern Plains, with a consequent increase in surface temps, likely going back above normal.
242 PM PDT Sat Jun 19 2021 Widespread triple digit heat expected for the lower elevations into Sunday.
Winds have begun to weaken in the wake of today's cold front, and this trend will continue overnight.
956 PM CDT Sat Jun 19 2021 Latest 18z surface analysis shows ridge of high pressure over Minnesota and northern Iowa. The biggest issue will be how fast does the atmosphere/forecast area recovers from the morning convection--with cloud debris or lingering shower activity--when surface cold front moves across the region during the afternoon and evening. The Sunday afternoon convection should rapidly depart in the evening hours as the cold front sweeps southeastward through the region.
1055 PM EDT Sat Jun 19 2021 Currently - A surface through lower level Atlantic ridge extending westward across South Florida and into the Gulf of Mexico, is responsible for light to gentle east to southeast breezes across the Keys and surrounding waters. Temperatures are slowly falling through the lower 80s under mostly clear to partly cloudy skies. Short Term Update - The surface through lower level ridge will slip a bit further southwards through the overnight period. Expect overnight lows in the lower 80s with dew points remaining stuck in the upper 70s. A ridge across South Florida will shift southwards into the Keys through the overnight.
RAP model data shows that this heavier rain is forming along the nose of the low-level jet and moisture transport maximum, within a low and mid-level theta-e convergence axis, and with precipitable water values around 2 inches. The forecast is generally in good shape with PoPs peaking this evening, then tapering off overnight as the low center moves east.
For Sunday, looking at near to critical fire weather conditions ahead of the cold front for most of Carbon and Albany counties. Meanwhile, the cold front is progged to move through the forecast area late this evening into tomorrow morning. This will bring much cooler temperatures into the area on Sunday.
854 PM EDT Sat Jun 19 2021 High pressure will gradually weaken over the region, allowing for increasing moisture to move into South Florida tonight into tomorrow. High pressure across the region with southeasterly wind flow across the area. As Tropical Storm Claudette moves northeastward across the southeastern CONUS, the ridge across the region will recede northeast as well. High temperatures each afternoon will be in the low to mid 90s with heat indices soaring into the triple digits once again on Sunday.
The Atlantic high pressure ridge axis will begin to dip south of Lake Okeechobee through the day on Sunday, gradually veering the low level flow southerly to south-southwesterly. Afternoon highs will be warm once again with highs in the low 90 with upper 80s along the coast. Overnight lows will once again be in the low to mid 70s. (Modified Previous Discussion) A general south to southwest flow around 10-15 KT will continue as the Atlantic ridge axis oscillates between central and south FL.
Short term guidance is in good agreement depicting the upper level pattern at 12Z Sunday consisting of a 591 dm cut-off ridge over the Desert Southwest/far northwestern Mexico, and broad northwesterly flow across the northern plains southward to the northern edge of the southern plains. Temperatures will rapidly increase into the upper 90s/low 100s ahead of this front, before strong north winds behind the front put a halt to daytime heating and usher in much cooler air.
For the rest of today, a cold front is progged to make its way southeast reaching north central Kansas by early this afternoon. As the cold front marches across the forecast area this afternoon, a weakening cap and increased lift along the boundary will likely lead to convective initiation around 5-7pm. The position of the cold front by late this afternoon will determine which areas will be impacted by storms; at this time it appears the front will be draped from Hiawatha to Council Grove with the best chance for severe storms southeast of this line.
As the tropical remnants depart to the east and our next cold front approaches from the northwest, our low level flow will increase from the west southwest tonight.
If convection forms, it should be high-based within hot/deeply mixed environment ahead of the trough. Temperatures should be similar to previous days, although strengthening and veering flow ahead of the front will support temperatures a couple degrees warmer, particularly over northern Oklahoma. Later in the evening and overnight, amplifying trough across the northern Plains and Midwest will nudge a surface cold front into the area.
(Today and tonight) Our area remains on the eastern periphery of an upper level ridge, which is centered over the Desert Southwest. With some strengthening of the 850mb thermal ridge, highs today are expected to be 2-3 degrees warmer than yesterday.
251 AM EDT Sun Jun 20 2021 Early this morning, vort max wrapping over NE Gulf into upper low associated with Claudette continues to produce widespread showers over the N Nature Coast and isolated thunderstorms in NE Gulf and this activity expected to continue through sunrise into mid morning before moving inland.
Breezy conditions could continue overnight, but with the higher humidity should not create any issues. A cold front will cross the area late this afternoon and cause winds to turn northerly. Northerly winds will bring in noticeably cooler and more moist air to the area tonight. The higher amounts are expected in the foothills because of the low-level flow and thermodynamic profile working to produce upslope enhancement there.
141 AM EDT Sun Jun 20 2021 A weak low pressure trough will remain nearby today.
With drier air in the lower layers of the atmosphere, storms would be even more prone to create gusty downburst winds with less rainfall.
A cold front will cross the state from north to south today, bringing with it much cooler temperatures, gusty northwest winds, and scattered showers/isolated thunderstorms.
Looking at the bigger picture, a potent trough is digging over the Northern Rockies, forcing the western ridge to retreat to the Desert Southwest. Another strong trough is moving across the Central Plains early this morning, but this wave will damp as it lifts ENE into the Great lakes this afternoon. We'll see scattered high clouds this morning but should see a fair amount of sun today which will push temperatures into the low/mid 90s across most of the Mid-South. The main focus for this forecast package turns to the early week cold front.
The initial discrete storms will pose a threat for all hazards, with mid-level steep lapse rates and a moderate-high CAPE profile (3000 to 4000 J/kg) favoring large to very large hail, and the low level wind profile and low cloud bases favoring the chance for tornadoes.
Clouds should help keep temperatures in the 80s for most cities, though if skies clear, some sites could push into the low 90s.
Discrete thunderstorms will begin to develop along the cold front, extending from central Kansas into northern Missouri during the late afternoon and early evening along an axis of significant instability. However, this severe storm threat looks relatively brief as the atmosphere becomes increasingly capped into the late evening and overnight hours, which should lead to a gradual weakening trend as the storms push southeastwards into the Highway 54 corridor.
High pressure will gradually weaken over the region, allowing for increasing moisture to move into South Florida tonight into tomorrow. High pressure across the region with southeasterly wind flow across the area. As Tropical Storm Claudette moves northeastward across the southeastern CONUS, the ridge across the region will recede northeast as well. High temperatures each afternoon will be in the low to mid 90s with heat indices soaring into the triple digits once again on Sunday.
322 AM CDT Sun Jun 20 2021 Key messages: - One last hot and humid day (for this stretch anyway) before a cold front moves through tonight, cooling things down through the middle of the week. - Severe storms are possible late this afternoon and this evening as that cold front moves through the area. A strong cold front is expected to move through the area late this afternoon into this evening. Much cooler temperatures will move into the area behind this front with an area of high pressure settling across the middle of the country.
358 AM CDT Sun Jun 20 2021 The main forecast challenges to start off the week include another round of moisture this evening into tonight and a big swing in temperatures with a cold front passage followed by a building ridge. A strong cold front quickly drops through the forecast area this morning, resulting in a switch to northerly winds and a quick uptick in speeds. As of 09z, the front was crossing the Black Hills and encroaching on the Pine Ridge. Throughout the day, a longwave trough digs into the northern Plains and Upper Midwest. The wave will greatly increase forcing in the mid levels, while some upslope flow at H85 provides some lift in the lower levels.
345 AM CDT Sun Jun 20 2021 A low pressure system centered over eastern SD attm will steadily track eastward into southern MN through mid afternoon. Winds should increase from the northwest at 15 to 25 mph through this afternoon, following cold frontal passage. Cooler, drier, and more stable air will steadily filter into the area from southern Manitoba. Otherwise, daytime high temperatures should range from the middle 60s into the lower 70s across he area. expect clearing skies and light northerly winds, with nighttime temperatures cooling into the lower 40s across the area, and with temperatures dropping into upper 30s along the hiline.
This feature will make its way south this morning into northwest Montana, pushing cooler air ahead of it.
430 AM EDT Sun Jun 20 2021 The axis of a weak western extension to the ridge over the western Atlantic lies across the southern Florida peninsula. An upper trough digging over the southeast U.
1233 AM EDT Sun Jun 20 2021 A cold front will cross the region overnight.
Southerly flow will continue to keep us hot and humid with highs reaching near or into the low 90s this afternoon. Strong southwesterly flow will keep temperatures very warm overnight minimums in the low 70s with mid 70s across more urban areas.
A cold front will push southward across the region today in the wake of this wave with soaring hot temperatures just ahead of the front.
Temperatures seem to be trending well for us to reach our overnight lows in the lower to mid 70s, although a few locations across our far northern zones could see the upper 60s by morning.
This trough should be near a Guymon, OK to Vega, Tx line by late this afternoon. This trough could spark an isolated thunderstorm to two late this afternoon, but it looks like the moisture and lift will be lacking, so we think the better chance of showers and thunderstorms will come tonight with the cold front that moves south across the region.
345 AM CDT Sun Jun 20 2021 A low pressure system centered over eastern SD attm will steadily track eastward into southern MN through mid afternoon. Cooler, drier, and more stable air will steadily filter into the area from southern Manitoba. Otherwise, daytime high temperatures should range from the middle 60s into the lower 70s across he area. expect clearing skies and light northerly winds, with nighttime temperatures cooling into the lower 40s across the area, and with temperatures dropping into upper 30s along the hiline.
By this time the cold front should be moving into our northern zones. After another hot afternoon today, we remain on track for a nice cool down tomorrow as the cold front discussed above sweeps through the South Plains during the morning. Depending on the duration of the post-frontal stratus, some locations may not rise out the 70s, though highs in the lower to middle 80s look more likely for the central and southern zones.
Models indicate low level flow will back overnight in response to a short wave trof digging into the Plains States. This boundary/warm front may trigger a few showers after midnight. An approaching cold front will trigger showers and thunderstorms across western TN and northern MS Monday afternoon. Rain chances will remain high Monday night as a band of showers and thunderstorms moves into north Alabama ahead of an advancing cold front.
Upper ridge begins to build back into the area though Monday afternoon.
Ridging aloft and compensating subsidence in the wake of the tropical depression will combine with solar heating to produce temperatures in the lower 90s in these areas. In our eastern higher elevations, temperatures will be held in the lower to middle 80s by areas of cloud cover. This activity will preclude a cold front stemming down from a fairly deep upper trough. The second "wave" of storms is expected later in the evening/overnight hours, as a line of storms moves along the cold front.
As the tropical remnants depart to the east and our next cold front approaches from the northwest, our low level flow will increase from the west southwest tonight. The cold front and its supporting upper trough will move in from the northwest during the day on Monday. The beginning of the extended looks to be very active, as a potent cold front moves through the area.
407 AM CDT Sun Jun 20 2021 Our much anticipated precipitation will be working its way across the region throughout the day ahead of a strong cold front. Winds behind the cold front will be breezy through the afternoon and into the overnight hours as strong CAA spreads across the area into Monday.
Overall, though, any thunderstorms should remain weak and likely not cause strong wind gusts or large hail, but northerly winds could become gusty at times due to the passage of a secondary cold front.
An upper level Vort max moving through the upper level low over the Southeastern states associated with Tropical Depression Claudette along with good upper level divergence is supporting a large area of showers and isolated storms over the northeast Gulf waters and the northern Nature Coast early this morning, while mainly dry conditions with a large canopy of mid and high level clouds were being observed over the remainder of the forecast area. With morning sounding data showing decent ML Cape (2251 J/Kg) dry mid level air, and cooler temperatures aloft (-8C at 500Mb) as well as steepening surface to 3km lapse rates (7.
Closer to home, weak upper ridging aloft was still holding on acrs the region. As this occurs, a deepening upper trof wl briefly set up ovr the eastern half of the nation.
614 AM CDT Sun Jun 20 2021 The main forecast challenges to start off the week include another round of moisture this evening into tonight and a big swing in temperatures with a cold front passage followed by a building ridge. A strong cold front quickly drops through the forecast area this morning, resulting in a switch to northerly winds and a quick uptick in speeds. As of 09z, the front was crossing the Black Hills and encroaching on the Pine Ridge. Throughout the day, a longwave trough digs into the northern Plains and Upper Midwest. The wave will greatly increase forcing in the mid levels, while some upslope flow at H85 provides some lift in the lower levels. A large upper ridge dominates the synoptic pattern mid to late week for most of the central US.
Southerly flow will continue to keep us hot and humid with highs reaching near or into the low 90s this afternoon. Strong southwesterly flow will keep temperatures very warm overnight minimums in the low 70s with mid 70s across more urban areas. Progressive upper wave will carve out a broad eastern CONUS trof Monday and Monday night, driving an unseasonably strong cold front through the Ohio Valley during the day. Showery weather will follow on Monday night with a post-frontal precip shield ahead of the upper trof axis.
Dry conditions are likely to continue through the entirety of Sunday, but there is a conditional chance of convection as a cold front plods southeast across the area by this afternoon. The cold front will bring in the month's coolest temps so far. Monday morning's temps will be about 10F cooler than this morning's lows and will be sub-normal. Ridging over Rockies helps lift heights over the course of the week.
Showers will end from west to east Monday behind a strong cold front.
This activity will preclude a cold front stemming down from a fairly deep upper trough. The second "wave" of storms is expected later in the evening/overnight hours, as a line of storms moves along the cold front.
The 12z sounding at KEY does highlight a moistened environment in the low- levels, in stark contrast to its 00z counterpart from last night. CIMMS satellite-derived vorticity analysis is depicting we are in the southern periphery of an expansive ridge across much of the Atlantic.
An upper ridge will bring a warming trend today and Monday with temperatures peaking on Monday.
A cold front will cross the state from north to south today, bringing with it much cooler temperatures, gusty northwest winds, and scattered showers/isolated thunderstorms. Temperatures will remain cooler, with highs ranging from the mid 60s to mid 70s. Upper ridging will nudge closer to the region, gradually deamplifying through mid week, promoting a warm up.