Aikyam-Lab/Synoptic-Bench huggingface dataset:
An associated warm frontal boundary will generate additional showers. Trough across the eastern CONUS deepens, with ridging upstream amplifying, resulting in a dry northwest flow regime. Hot air returns for the latter half of the work week with a slight uptick in humidity but nothing too stifling, with the ridge to the west migrating overhead and flattening resulting in light zonal flow.
Temperatures will be a little warmer today with the break in the clouds allowing for some daytime heating to occur. Afternoon highs will be in the low 90s, with those along the coast getting a break from the heat in the mid/late afternoon, once winds pick up as the sea breeze moves in. The Atlantic ridge axis is positioned across Central FL, and as the sea breeze develops this afternoon, winds will become southeast at 10-15 knots.
At the surface, a cold front associated with the aforementioned wave will stall out from somewhere south of Danville to Quincy. Southwest flow will continue to filter in a warm, moist airmass with high temperatures climbing into the low to middle 90s by the afternoon hours on Sunday. Elevated convection associated with the low looks to spread across Iowa/northern Illinois and points northward to start the day on Sunday, keeping much of our area dry. Strong to severe storms are possible especially north of I-72 where the better shear will be located nearest to the low with all severe hazards possible.
A better chance of showers and thunderstorms will occur on Sunday night as a second, deeper trough moves through the area which will bring the front through Missouri and Illinois. Even with the outflow boundary moving southward today, we will still have the potential to have highs climb back into the low to mid 90s with dewpoints in the low 70s, particular if they pool along the boundary. Then tomorrow, the warm front will lift north of the area, and with south to southwest winds and 850mb temperatures around 20C, we should have highs climb into the mid- upper 90s in the metro area.
525 AM EDT Sat Jun 19 2021 Expect increasing atmospheric moisture this afternoon, with tropical moisture moving into the region tonight through Sunday night, with low pressure tracking east across the region.
Significant theta-e advection along the warm front will help drive it poleward.
623 AM CDT Sat Jun 19 2021 Temperatures today will be 2-3 degrees cooler than yesterday and dew points a few degrees cooler. Highs will be in the low to mid 90s with max heat indices of 95-105.
Southerly low level flow strengthens ahead of an approaching cold front. Dew points reach the lower 60s across southwest Neb and upper 50s to the north. The greatest convergence will occur across western Nebraska along the theta-E axis riding up the High Plains. The low level jet also kicks in before the cold front. An upper trough begins to settle into the northern tier of the country, and the H3 jet dips into the state. The workweek starts off on a mild note with the upper trough still in play for the upper Missouri and Mississippi Valleys. The trough is quickly booted east midweek by an amplified ridge centered over the Four Corners.
A weak cold front pushed south into west central Kansas late last night and had become nearly stationary during the overnight hours. We think winds will become more southwesterly by afternoon which will allow afternoon temperatures to top 100F again, ahead of the next much more significant cold front. A strong cold front will push south late Sunday/Sunday Night as a fairly deep (by mid-late June standards) trough axis in the middle troposphere moves across the Northern Plains/Midwest region.
/Issued 253 AM CDT Sat Jun 19 2021/ The hot weather will continue through this weekend, though it will be "less hot" today across the area as mid level ridge continues to move back west for a few days.
Decided to lower the highs today a category, based on the current amount of cloud cover. On Sunday afternoon, more of the same but with upper flow switching to the west and southwest as a trough digs in over the Plains. Perturbation ahead of the trough may help things fire up as well.
Elsewhere, the nrly low-level flow has brought in some lower dewpoints which is making for a relatively pleasant night with temps generally in the lower 70s. No changes were made this morning to the inherited Coastal Flood Advisory as elevated tide levels will likely continue causing minor flooding issues near the lower Acadiana bays and Atchafalaya Basin. Rain chances look to continue increasing through the day on Sunday as the higher moisture surges farther inland while daytime heating and mesoscale features help drive convection.
/issued 238 AM CDT Sat Jun 19 2021/ Today the subtropical ridge will remain across AZ with a nely 5h winds and little change into 85h-7h temp profile, including the 5h heights.
The upper ridge persists across the southwest CONUS this morning with a stationary surface boundary draped from southwest Kansas into northeast Kansas and extending into southern Wisconsin. Today should be slightly cooler than the past few days thanks to cooler 850mb temps, although it will still feel plenty hot with highs reaching the mid to upper 90s and heat indices around 100 degrees. Precipitation exits the area Sunday morning as a stronger cold front approaches from the northwest. The front is progged to move through the forecast area Sunday afternoon and evening as a longwave trough ejects across the Plains.
Due to the cloud cover and rain chances, temperatures will run quite a bit cooler than recent days, with highs only reaching the upper 70s to lower 80s.
A trough of low pressure will begin sliding south out of British Columbia today, allowing for increased west to northwest winds to develop across the region. Expect an increase in clouds later today, as a Canadian cold front moves north to south this evening and during the day Sunday. Sunday will be around 10 degrees cooler compared to recent days, with breezy north to northeast winds (particularly in western Montana).
GOES Water vapor imagery/Derived Motion Wind/NWP model initiations depict an upper level trough over the region. Deterministic GFS/ECMWF/NAM predict this weak upper trough to remain quasi-stationary over the region during the period, while the region of greater moisture advects onshore the CWA Sunday.
A slightly enhanced pressure gradient between the recently formed Tropical Storm Claudette and the high pressure centered over the western Atlantic will support moderate east to southeast breezes across the coastal waters through this evening. A decent amount of moisture is encased in the low-levels this morning, which may allow for isolated shallow showers as we head into the afternoon, so have retained 10% for the rest of today.
Post-frontal showers/iso storms are also expected across the area on Sunday, as a jet streak crosses the northern Plains and cooler air aloft results in marginally steep lapse rates.
A strong ridge of high pressure will result in excessive heat through this weekend. The upper high remains centered in the Four Corners with easterly flow noted on the KTWC 210619/00Z sounding up through nearly 300 mb. Therefore, even with a favorable flow pattern, it will be difficult to generate much in the way of storms except in the high terrain along the rim and possibly over the mountains of Cochise and Graham counties. An Excessive Heat Warning remains in effect through 9 PM MST Sunday for much of the lower elevations of southeast Arizona.
/Issued 230 AM CDT Sat Jun 19 2021/ An upper level short wave trough is expected to move southeast from Colorado into western Kansas late this afternoon and this evening. On Sunday, the models do agree that another short wave trough will move this way in the northwest flow. But they do not agree on the timing of the cold front moving through. The GFS model is the most agressive with bringing the cold front through and it also has the most precipitation with it. Highs on Sunday could be in the 100 to 106 degree range across the southeast half of the area as long as the cold front holds off until later in the afternoon.
SHORT TERM (Today through Sunday): A 500mb low/trough across east Texas will provide subsidence across most of south Texas today but low to mid level moisture across the western Gulf of Mexico will encroach on the lower Texas coast this afternoon to warrant a mention of isolated showers across the coastal sections of the CWA today. Any rain chances tonight through Sunday should be confined along and offshore the lower Texas coast.
Upper level ridging remains in northern Arizona with a weak impulse off the coast of California for today. For tomorrow, the ridge builds west slightly with another day of warm to hot temperatures.
Expect VFR conditions to prevail across the Rio Grande Valley the rest of this morning into this afternoon as a 500mb low/trough across east Texas continues to provide subsidence across south Texas. /issued 410 AM CDT Sat Jun 19 2021/ SHORT TERM (Today through Sunday): A 500mb low/trough across east Texas will provide subsidence across most of south Texas today but low to mid level moisture across the western Gulf of Mexico will encroach on the lower Texas coast this afternoon to warrant a mention of isolated showers across the coastal sections of the CWA today. Any rain chances tonight through Sunday should be confined along and offshore the lower Texas coast.
/issued 335 AM EDT Sat Jun 19 2021/ Potential Tropical Cyclone Three is currently positioned over the north central Gulf of Mexico and is forecast to move north- northeast today, then turn to east-northeast later this weekend as it moves inland. High pressure east of Florida and Potential Tropical Cyclone Three in the north central Gulf of Mexico are setting up southeasterly and southerly flow over the coastal waters today. As the tropical system moves north this weekend, high pressure will build back into the eastern Gulf, with southwest to south west winds holding through the first half of the week.
/issued 251 AM CDT Sat Jun 19 2021/ Overall today will be another quiet day as an upper high continues to dominate the southwestern US. The will allow for terrain induced convection to develop across Colorado and northern New Mexico and should also weaken the upper high slightly.
302 PM EDT Sat Jun 19 2021 The overcast cloud deck that was in place this morning has mostly eroded over the Lower Keys but gradually moving out of the Middle and Upper Keys.
In the meantime, moist upslope flow into the CO front range and a mid-level upper trough moving through the northern and central plains this evening will initiate thunderstorms in western KS.
329 PM CDT Sat Jun 19 2021 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.
Breezy northwest winds will continue across the Northern Rockies through the evening hours as a trough of low pressure slides south out of British Columbia. The Canadian trough and associated backdoor âcoolâ front will sweep across western Montana tonight into Sunday morning.
Expansive dome of high pressure which has produced the extended heat wave across the Desert Southwest and beyond will begrudgingly retreat a bit further southeast during the upcoming work week. This is in response to a trough of low pressure along the central California coast.
217 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.
1224 PM CDT Sat Jun 19 2021 Upper level high pressure ridge will remain in control tonight and Sunday, although a disturbance digging out of the northern Rockies into the central plains tonight will lead to surface pressure falls and increasing southerly low level flow from the surface to around 2000 feet above the ground. /issued 251 AM CDT Sat Jun 19 2021/ Overall today will be another quiet day as an upper high continues to dominate the southwestern US. The will allow for terrain induced convection to develop across Colorado and northern New Mexico and should also weaken the upper high slightly.
Sky cover continues to gradually increase across the TN Valley this morning as moisture advects northward from TS Claudette, which is currently moving nne across the Lower MS Valley. Overall the lowest cigs/visb and heaviest convection will be at CHA tonight. CDG Chattanooga Airport, TN 70 86 72 88 70 / 60 50 40 80 80 Knoxville McGhee Tyson Airport, TN 68 86 72 88 68 / 30 30 30 70 80 Oak Ridge, TN 67 86 70 88 67 / 30 20 20 70 80 Tri Cities Airport, TN 65 86 67 88 66 / 20 30 30 50 80.
Sky cover continues to gradually increase across the TN Valley this morning as moisture advects northward from TS Claudette, which is currently moving nne across the Lower MS Valley. TD Chattanooga Airport, TN 85 70 86 72 88 / 30 50 50 40 80 Knoxville McGhee Tyson Airport, TN 87 68 87 72 88 / 10 30 50 30 70 Oak Ridge, TN 88 68 87 70 88 / 10 20 40 20 70 Tri Cities Airport, TN 87 65 86 67 88 / 10 20 30 30 50.
We'll see some welcome relief from those concerns as a strong cold front is expected to cross over the CWA late this evening into tonight. Nor wouldn't be surprised to see a few snowflakes on the highest peaks of the Bighorns.
A much cooler start is forecasted to start the work week with highs in the lower 60s and overnight lows in the upper 30s. An upper level trough pivots across the region with split jet flow moving across the Central US. However, a secondary push of moisture is evident in the CAMs Sunday afternoon and evening from a cold front dropping out of the Canadian Prairies. If stronger storms do manage to manifest I would expect them to be in the afternoon in association with the aforementioned cold front as it drops southeast. Some unseasonably cold air will filter in behind the exiting cold front to start the work week with 850mb temps closing in on below freezing. This will translate into highs near the lower 60s and overnight lows near the upper 30s.
A subtropical ridge centered over AZ will expand over the SW U. In response, mid-lvl hghts will increase and the low-lvl thermal ridge will shift further ewd, encompassing much of SE NM and West TX. A Heat Advisory is now in effect for the aforementioned regions as well as the western half of the Permian Basin where temperatures will reach the lower end of advisory criteria. Forecasted highs in the higher elevations (5000+ft) are still expected to reach excessive heat criteria (100+F) and we will go ahead and upgrade to an Excessive Heat Warning for the Guadalupe, Davis, and Chinati Mtns.
A weak mid level trough also linger over our region. With considerably less cloud cover than today, temperatures will top out close to normal in the lower 90s.
As the center of Claudette shifts ENE roughly along the I-85 corridor overnight, expect the highest coverage of precipitation to exist across the southeastern portion of the area.
311 PM CDT Sat Jun 19 2021 One more hot and humid day is in store Sunday before much cooler.
236 PM CDT Sat Jun 19 2021 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.
While any established storm could become a supercell, the high T/TD spread in the 20-25 degree range will keep storm bases rather high, and should enhance downdraft potential above any tornado potential. With the track of the mid level low glancing the area, expect the highest impact from this complex across areas south of I-80, perhaps into the far northern reaches of Missouri. With most of the forecast area remaining untouched from Saturday/Saturday night convection expect most of the area to remain warm and muggy and well primed for the cold frontal passage Sunday evening through Sunday night. Expect the surface cold front to impinge into the northwestern corner of Missouri late Sunday afternoon, and continue to press E/SE through the evening.
Elsewhere, high clouds and some mid-level Cu have developed keeping temperatures a few degrees cooler than yesterday.
Warm and dry conditions today under a weak upper level ridge. The ridge does get suppress some by a passing upper level trough and cold front which will keep temperatures a few degrees cooler than yesterday.
1213 PM CDT Sat Jun 19 2021 Temperatures today will be 2-3 degrees cooler than yesterday and dew points a few degrees cooler. Highs will be in the low to mid 90s with max heat indices of 95-105.
That sunshine in the morning is the result of the upper level ridging, that will be building over the Great Lakes, in response to the digging polar jet core over Montana in the morning. As is typically the case, the warm front being where it is, enhances the risk for tornadoes during the evening (near I-94).
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.
High Fire Danger through this Evening for Much of NE A cold front is beginning to move through the area from west to east. Although relative humidity will recover later this evening, the high fire danger will lag as showers and thunderstorms are not expected to produce a wetting rain and the threat for lightning to cause a new fire start exists.
The 12Z UA data show that the Desert Southwest anticyclone is still firmly in place while the main belt of the Westerlies resides along the northern tier of the CONUS. Over the forecast area, a stationary boundary has started to lift north slightly this afternoon as it transitions into a warm front. The main threat for storms to impact the area comes into late this evening and overnight as the storms of the High Plains begin to form cold pools and congeal into a line of storms. Inverted V type soundings with high freezing heights and weak low level shear suggest that damaging downburst winds could be the main threat with hail being a lesser threat if sufficient mid level rotation can become established with a storm.
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.
Rux PREVIOUS DISCUSSION: Warm, dry, and breezy conditions are expected today before a cold front tracks across the region and turns winds to the northwest.
High temps on Sunday will range from the lower 90s east (slightly cooler at the beaches) to a skosh above the century mark out west.
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.
Upper level high starts to backtrack to the west on Sunday as the upper trough over the Central Plains digs a little farther south, but upper ridge axis remains draped across the area. Mild again tonight with lows in the lower 70s.
Will keep some chance PoPs going through tonight, with the highest PoPs this evening and overnight. Don't really see much of a focus for convection on Sunday, as warm advection ahead of the next trough may tend to cap things off. Models suggest an upper trough will amplify over the Great Lakes Sunday night, with the associated cold front possibly making into the northwest zones late Sunday night. Considering low level thickness progs, the GFS MOS guidance highs Sunday and the lows Sunday night may be a little on the cool side.
Also, there is an upstream MCS over the Lower OH Valley that appears to be dwindling as it runs into a more stable environment in the wake of earlier convection over northern and central KY. Southern locations will experience more in the way of ridging in the lower and mid levels with subsidence north of the tropical system moving across the southeast and should remain dry this afternoon and this evening.
High pressure will remain centered across the Desert Southwest through the weekend. A weak cold front will cross Saturday night into Sunday, bringing slightly less warm temperatures. High pressure remains centered over the Desert Southwest this morning as an upper trough slides over the top of the ridge. With daytime heating, anticipate additional convection to fire over the higher terrain, focused primarily over central and southern Utah. The previously mentioned trough will bring a mostly dry front across the area from north to south this evening into Sunday morning.
Meanwhile at the surface, a warm front was analyzed across KS. This moisture will try and work northward late this afternoon and early this evening as the low-level flow veers more to the southeast. This front will cross the area Sunday ushering in a cooler and drier airmass from Canada.
Consideration was given to expanding these products to some of the higher elevations, however humidity values in the central and northern mountains as well as fuel status remain just outside of critical thresholds.
Low pressure tracking from Kansas into the southern Great Lakes will help pull a warm front northward through central Illinois Sunday morning. A cluster of storms associated with the low will remain mostly off to the W/NW, but will come close enough to warrant low chance PoPs along/northwest of a Rushville to Bloomington line. Think much of the day Sunday will be very warm and dry until late afternoon when the trailing cold front approaches from the northwest. Given the highly unstable environment characterized by SBCAPEs in excess of 3000J/kg and 0-6km bulk shear increasing to 35-40kt, damaging wind gusts and hail will be possible as the line traverses the area during the evening.
A stationary front that was straddled southwest-east across our area this morning is looking a little more like a warm front this afternoon as expanding mid and high clouds have generally cut the temperates several degrees off the kind of heat we saw yesterday at this time.
818 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.
A strong ridge of high pressure will result in excessive heat through this weekend. Strong high pressure over the desert southwest will continue to bring temperatures above average most of the coming week.