Aikyam-Lab/Synoptic-Bench huggingface dataset:
The aforementioned upper-level blocking pattern will persist through much of the period with the low lingering over New England finally transitioning east by the end of the week. An isolated shower cannot be completely ruled out over the higher terrain during the late afternoon each day but the vast majority of the forecast area will remain dry through the week. Opted to undercut NBM a degree or two as deterministic runs reside on the warmer side of the spread. Broad ridging centered over the central CONUS will be the dominant feature this weekend. There is high confidence that high pressure will maintain VFR with exception for peri- dawn fog at terminals nearest the water sources. Broad Eastern CONUS ridging will support general VFR with exception for incidents of peri-dawn fog, no appreciable precipitation is forecast for the foreseeable future.
240 PM EDT Tue Jun 30 2020 High pressure over Quebec extends ridging toward the eastern lakes as well as Huron. The high will retrograde westward, and be directly overhead by late Wednesday. High Impact Weather Potential: Minimal Pattern/Forecast: Current upper level pattern features continued ridging across the Great Lakes bound on either side by nearly stationary upper level lows; showcasing the omega block that has been over the CONUS the past couple days.
The complex trough centered over northwestern Montana continues to rotate and will move slowly north during the short-term period. A weak wave will rotate around the low and affect northern portions of the forecast area later this afternoon and early evening with a slight chance of showers and thunderstorms. Drier and warmer air will move across the forecast area on Wednesday with afternoon high temperatures expected to be near normal.
The upper level low pressure system continues to meander across the northern Rockies today causing rain over much of the area as it goes. The low is now centered over Wyoming with another low forming on the east side of the Continental Divide just north of the border in Alberta.
Despite the heat, the aforementioned high will bring dew points down into the lower to middle 60s during the afternoon hours, which should prevent heat index values from getting much above the air temperature.
215 PM EDT Tue Jun 30 2020 A ridge axis extends west from a western Atlantic ridge across the Sunshine State. Meanwhile, some cu continues to cling adjacent to the Lower Keys. Surface observations show temperatures in the lower 90s with dew points in the mid to upper 70s, making it quite muggy and hot.
With the strong 850 mb thermal ridge and high dewpoints, heat index values of up to 107 will be possible. Although the thermal ridge may not be quite as strong on Wednesday, it will still be plenty hot and muggy, with highs generally in the 96 to 103 degree range, and heat index values in the 99-105 range.
154 PM PDT Tue Jun 30 2020 A trough of low pressure over the western states will weaken with high pressure to the south and east expanding into southern California later in the week through the weekend.
As rain continues and cloud cover lingers, temperatures remain subdued in the low and middle 70s.
Upper trough continues to spin over the Northern Rockies, with one vort max lifting through western ND and another rounding the base of the trough and moving through WY. This should finally push the convective activity that has only been clipping our northwestern counties further eastward into the CWA as the weak cold front moves east. With dew points in the low and even mid 70s, there is plenty of moisture to work with and ML CAPE values are near or over 3000 J/kg across most of the western and central CWA. Kept highs in the low to mid 80s with cloud cover however. The upper ridge remains in place and will continue a pattern of warmer temperatures across the region.
A negatively-tilted mid and upper-level trough will eject from the Rockies into the northern Plains by this evening, setting the stage for an active thunderstorm event as a frontal zone also sharpens and shifts eastward. This convection will likely limit diurnal heating across western and portions of central ND which could limit the higher end of the severe threat this afternoon/evening, however, more robust ascent is expected as the negatively-tilted trough swings through and this should be enough to spark more organized convection late this afternoon or evening.
143 PM EDT Tue Jun 30 2020 Upper low pressure will linger across the area through Wednesday with scattered showers and a few afternoon or early evening thunderstorms.
1113 AM MDT Tue Jun 30 2020 Current surface analysis shows cool front still nearly stationary across western SD, generally from near Lemmon to east of Pine Ridge. Upper level analysis shows low pressure over far southwest MT, with south-southwest flow across the northern high Plains. Upper level low will track northward across western MT as the ridge to the east of the region remains strong. A wide range of temperatures are expected today, from the lower 70s across northeast WY, the Black Hills, and far northwest SD to the upper 80s over south central SD. Upper low moves into western Canada Wednesday morning with a much drier airmass in place. Upper level ridge rebuilds back to the west across the Plains late week, with hot conditions returning through the holiday weekend.
Rain chances are expected to be mainly 40-60% across the area with highs in the low to mid 90s.
as high pressure will basically remain stationary over the Upper Great Lakes.
1250 PM CDT Tue Jun 30 2020 Stratus has developed again this morning across the area, with plenty of moisture (as displayed by soundings) through the lowest 5k ft. Models have come into more general agreement regarding the timing of today's front/trough and convective development. 5 inches and given the amount of moisture present in the lower levels. Temperatures Wednesday will be slightly cooler as well behind the front.
Medium High pressure to our east and a trough of low pressure to our west will essentially remain the scenario this period. Noting some westward push of drying with precipitable water values (on both the NAM and GFS) with high exerting more influence than any troughing.
Temperatures continue to be in the low 90s with dewpoints in the upper 70s bringing heat indices to the 100s, even with some isolated convection briefly dampening a few spots.
High pressure remains anchored across lower MI with low pressure in the Plains. High pressure will largely dominate the area for the remainder of the week with a fairly light wind regime. This will keep wave action on the low side. Into the afternoon we will see slight chances for a few storms or showers primarily to the southwest given proximity to the upper level low that will be pushing slightly north/northwest.
329 PM CDT Tue Jun 30 2020 Pattern remains essentially stagnant, with meandering mid/upper low situated over the mid MS River Valley, and very moist and unstable air in place over the lower OH Valley. the flow around the upper low will become more nwly with time, and should support most activity moving sse down the river valley. Overall, severe risk looks to be on the low side, esp compared to the heavy rain potential. Eventually, as we head into Wed night/Thu time frame, upper level ridging should begin to build in from the west. Hot and humid conditions will remain, however, with highs up near 90 and dew points in the lower half of the 70s.
as high pressure will basically remain stationary over the Upper Great Lakes. For this period there will not be much change in the flow aloft, with the ridge axis of an omega block remaining across the Plains and western Great Lakes.
402 PM EDT Tue Jun 30 2020 Longwave pattern holding firm yet another day with deep troughing over the west coast and a cutoff low over New England.
Although drier at low- levels, rain showers will form and come off the mountains this afternoon and evening as the upper trough axis passes over the area.
The upper low will remain over southern Alberta, with dry southwesterly flow developing over the forecast area. The upper level ridge will rebuild back to the west across the Plains late in the week, with hot weather returning through the holiday weekend.
151 PM EDT Tue Jun 30 2020 Weak high pressure remains northwest of the region into the end of the week as a trough of low pressure develops over the local area. Low pressure swirling INVOF New England will remain the dominate system.
This system would tend to dive southeast into central Missouri late tonight and potentially reach the Highway 60 corridor by sunrise. Lows tonight will again fall into the lower to middle 70s. 2) The higher end of model guidance indicates that Excessive Heat Warning criteria (heat indices >= 110 degrees) may be in reach near the I-49 corridor.
A residual low level trough will provide the focus in these areas as MLCAPE values push near 2000 j/kg. A subtropical ridge will build in for the second half of the week into the upcoming weekend with mainly dry wx and above normal temps.
1041 AM PDT Tue Jun 30 2020 A slow moving weather system will bring showers, thunderstorms, and cooler weather through midweek.
Winds will gradually change to the west then northwest between 00Z and 06Z Wed, while becoming north behind a weak cold front there after. The base of an upper level trough will swing across the Panhandles today before lifting north into southwest Canada as an upper level ridge begins to build in southeast Texas. A low level thermal ridge sets up similarly to yesterday. A weak cold front will push south across the area Wednesday morning bringing with it light north winds and some shallow moisture. Low and high temperatures Wednesday may be up to 5 degrees cooler, but nothing significant.
Some weak low level jet support has enhanced this activity some with a few reports of small hail noted, but this support should continue to wane into the afternoon as the low shifts northeast.
1114 AM EDT Tue Jun 30 2020 An upper level trough will be over the eastern US through much of the week. Late in the week, the closed upper low will move east and should be replaced by a weak upper trough. Highs will be in the low to mid 90s with lows overnight near 70 degrees.
Mid-level ridging is then expected to build in with increased subsidence.
A departing low pressure system will bring a few showers and maybe an afternoon thunderstorm to far northeast Nevada this afternoon. Frost conditions are no longer widespread as morning temperatures increase well above freezing, therefore the frost advisory has been allowed to expire. A departing low pressure system will bring a few showers and maybe an afternoon thunderstorm to far northeast Nevada this afternoon. A steady west wind on the backside of the low will be present during the late morning and afternoon hours today and Wednesday.
Expect showers and thunderstorms to continue through the evening with lift from upper trough acting on a moist and unstable airmass.
Midlevel lapse rates are not quite as favorable compared to what we saw yesterday and a narrow mid- upper level ridge axis remains in place over the region between two broad longwave troughs over the western and eastern CONUS. Winds will remain light from the southeast with a more easterly component off the lake keeping the Illinois lakeside areas cooler, but otherwise highs in the mid 80s to around 90 will be similar to recent trends.
High-res models showing convection increasing again across the northwest by sun-up tomorrow morning and spreading south and east through the day, and this is supported by continued northwest upper flow pattern with weak short wave energy streaming across the region between the weak ridging to the northwest and closed upper low over the northeast.
318 PM EDT Tue Jun 30 2020 A trough of low pressure will remain over the Eastern United States through Wednesday keeping the Western Atlantic ridge more over the Bahamas extending westward into South Florida. The 500MB temps are also running a little bit cooler than normal for this time of year around -8 to -9C compare to -7C. Models continue to depict a weak mid-level high pressure in the Gulf of Mexico weakening and trough set up over the eastern seaboard. Given the light southwesterly flow regime the highest chances will be over northern and Lake regions and move generally eastward. As we move into the weekend a low pressure system will be dropping out of the TN valley into northern Florida. Uncertainty is higher in the extended depending how far south this low pressure system drops out of the TN valley.
The highest rainfall totals appear to be confined in a narrow corridor near the Twinsburg/Reminderville areas where up to three-quarters of an inch of rain has fallen. A subtle trough/lake breeze convergent boundary was located across portions of eastern Cuyahoga and Geauga Counties this afternoon with an isolated shower located near Middlefield. This is in response to a small amount of mid-level moisture from an upper low centered across southern New England which has snuck its way across Northeast Ohio. Highs remain on track today with cooler, low to mid 80s along the lakeshore with mid and upper 80s across Northwest and the inland areas of North OH. Highs will be cooler in the low to mid 80s along the lakeshore with mid to upper 80s to perhaps lower 90s elsewhere.
900 AM PDT Tue Jun 30 2020 A trough of low pressure over the western states will weaken with high pressure to the south and east expanding into southern California later in the week through the weekend.
BW Chattanooga Airport, TN 70 84 69 88 70 / 50 80 70 50 20 Knoxville McGhee Tyson Airport, TN 68 85 69 87 67 / 40 80 60 30 10 Oak Ridge, TN 68 85 68 88 67 / 40 80 60 30 10 Tri Cities Airport, TN 65 83 65 86 64 / 40 70 40 30 10.
As a negative tilt upper level low pressure trough kicks east through the evening and overnight, the cold front will push east. Despite this large instability, the issue continues to be the very warm air aloft +14c at 70h along with the modest six degree ll lapse rates across the east with the lower clouds. The ops models and hi- res models all continue to show that convection should develop along and behind this cold front as the mid level temperatures fall with 70h caa along with stronger lift from the upper level trough moving in. The best effective shear will also be along and behind the cold front into the evening hours. The period starts out with the western Dakotas in southwest flow and a ridge over eastern South Dakota and down through the central plains and much of the midwest.
WV imagery shows a broad upper trough ejecting thru MT into Canada, while farther SE the Gulf ridge has begun moving west, and still leaving West Texas and Southeast New Mexico under SW flow aloft. The ridge is forecast to make landfall in Mexico overnight, then begin developing north into Texas over the next few days.
- Cooler, more seasonal temperatures later in the week with some small chances for precipitation.
1244 AM CDT Mon Sep 19 2022 Late this afternoon through Monday: The weather pattern over the forecast area is becoming increasingly hot and humid as a strong subtropical ridge persists across the Gulf Coast states. /EC/ Upper ridging will be in control through much of the forecast period.
72 The upper level ridge positions over the Central Plains and Mid- South regions of the CONUS w/ the direct center over North Texas. At the surface, a high pressure center will track westward from the Tennessee River Valley into the ARK-LA-TX vicinity.
217 AM EDT Mon Sep 19 2022 High pressure will remain over central North Carolina through tonight. A weak cold front will approach the area on Tuesday night before weakening.
Otherwise, the dynamics and shear are fairly strong as a potent upper level trough moves through the area.
The southwest flow is courtesy of an upper low off the northern California Coast and a northern stream trough pulling east across southwest Canada. Those 700 mb temperatures when mixed down to the surface will result in 70s west of the Divide and over the south, while the areas east of the Divide will be in the lower to mid 80s. On Tuesday, an associated cold front associated with the northern stream trough will send down a cold front late tonight into Tuesday. In wake of the cold front expect gusty northerly winds, and high temperatures about 10 to 20 degrees cooler while the rest of the area will have similar highs.
/NEW/ /Overnight through Tuesday/ A stout late season mid level ridge will remain parked over the region through the middle part of the week keeping North Texas hot and dry for the next several days. Modest afternoon mixing will allow dewpoints to fall into the low/mid 60s.
401 AM EDT Mon Sep 19 2022 (Today through Tuesday) The high pressure ridge over the Mid-Atlantic states appears to be weakening but it will continue to keep things dry over dry for North and Central GA through the short term. With the ridge weakening moisture begins to increase across the region as well.
Guidance suggests the idea of isolated convection tomorrow afternoon, although with the developing area of high pressure both aloft and at the surface, it's unlikely. The best chance for this scenario would be in Texas counties, the furthest area from high pressure influence. Otherwise, the remainder of the short term period is hot and dry as deep high pressure settles over much of the eastern US.
This afternoon through Monday night Drier and warmer conditions will occur across the CWA today, as a ridge builds over the region, in response to the digging closed low.
- Above normal temperatures continue today and tomorrow, with cooler more fall like temperatures later this week.
411 AM EDT Mon Sep 19 2022 High pressure will move off to the south and east today.
A progressing Canadian low will dig a broad trough across the Manitoba and Saskatchewan tomorrow. This trough could bring severe weather to north central North Dakota Monday afternoon. A southerly low level jet will advect warm moisture into central and eastern North Dakota early morning through afternoon increasing dew points into the lower 60s. Temperatures are forecast to increase into the lower to mid 80s Monday afternoon increasing instability. A cold front will move the area Monday night through Tuesday bringing fall like temperatures back into the region. Precipiation is possible along the cold front Tuesday, but chances continue to diminish, I wouldn't hang a hat on it.
Tomorrow will be a virtual carbon copy of today with highs in the 80s/90s and isolated showers in the higher elevations west of the Pecos River.
Other models keeping mid state dry today in this continuing northwesterly flow pattern aloft as broad upper level ridging influences continue across southern plains. The persistence of broad upper level ridging influences across southern plains will continue to provide dry conditions to mid state region on Tuesday. Highs will continue to warm as upper level ridging influences begin to shift eastward.
Cold front pushing into northeast and western IA with very warm and unstable airmass ahead of the front. A weakening cold front will push through the cwa with winds becoming north to northeast. upper high remains centered over Texas and Oklahoma with broad ridging over the Great Plains. A weak wave topping the ridge may bring a chance of showers and storms Monday night over northeast IA and northern IL. Heat indices will be a few degrees warmer in the middle 90s.
In northwest flow aloft and with the strongest subsidence from an upper ridge well to our west, this is a possibility.
Highs will be about a degree or two warmer in the mid to upper 90s.
Winds generally remain light and variable, although expect increasing winds across central SD along the tightening surface pressure gradient (due to low pressure across the western Dakotas). Winds continue to strengthen into the afternoon as mixing increases and high pressure continues trekking east. Monday night remains well above average with ridge axis sliding overhead, flattening as mid level trough base and upper jet graze the International Border.
401 AM EDT Mon Sep 19 2022 A weak cold front will move south across the area today, bringing a chance of showers and thunderstorms.
Far southern Harney county will hold onto a chance of precipitation late tonight into Monday, as moisture wraps around a large upper low off the CA coast. Meanwhile, a strong upper low will remain off the California coast through Tuesday. Disturbances rotating around the low will bring a chance of showers to SE Oregon (mainly Harney County), along with a slight chance of thunderstorms Tuesday afternoon and evening. Southerly flow ahead of the low will bring a warming trend through the period.
The main forecast challenges are high temperatures with near record highs on Tuesday and cooler with precipitation for the remainder of the week. On Tuesday temperatures are expected to rise to the mid 90s, just before a cold front starts moving southeast into northeastern Nebraska by Tuesday afternoon.
(Today and tonight) The late season heat (near triple digit heat index values along and east of I-35) will continue today under the influence of an upper ridge.
A tap of monsoonal moisture will be drawn northward on the west side of the ridge, but it will be too far to our west (into NM, eastern AZ and southern CO) to provide any rain chances locally.
1032 PM CDT Sun Sep 18 2022 (This evening through Monday) Pressure heights will continue to rise as an upper ridge builds in from out of the south keeping us hot and dry through the short term.
159 AM MDT Mon Sep 19 2022 Synoptic Overview: The mid-latitude westerlies /SW flow aloft/ will recede to higher latitudes in this period -- as an amplifying upper level ridge (over the Southern Plains) extends northward over the Central Plains.
303 AM EDT Mon Sep 19 2022 Discussion/Marine - Showers and a few storms early this morning - Elevated convection will continue to develop in the vicinity of the I-94 corridor early this morning with moderate instability in place just ahead of the cold front. Fair wx is forecast for the rest of the day today as high pressure builds in behind the front and northwest winds slowly advect a drier airmass into our area.
Higher probabilities for storms are north into southern Canada, closer to the nose of the low level jet and in an area of weaker capping. Zonal flow aloft will start the period as the ridge breaks down and starts moving east.
The high shifts to southern Lake Michigan by days end.
/Issued 1126 PM CDT Sun Sep 18 2022/ /Overnight through Tuesday/ A stout late season mid level ridge will remain parked over the region through the middle part of the week keeping North Texas hot and dry for the next several days. Modest afternoon mixing will allow dewpoints to fall into the low/mid 60s. /NEW/ /Tuesday Night and Beyond/ The ridge will be at its peak strength around the middle part of the week as 500mb heights climb to near 595 decameters right over North Texas.
Meanwhile, strong upper ridging is centered over TX. Not much is expected to change for Monday with strong surface ridging over the Southern Plains as the cold front lifts back to the north. Behind the cold front we will finally get some relief from the heat on Thu with highs in the 70s and 80s. The upper low currently just off the Northern CA coast will start to lift northeast Wed and by Thu afternoon will be approaching the Northern Rockies. As this occurs some additional upper perturbations will lift out of the Great Basin and into the High Plains and will bring some small storm chances for Thu night into Fri.
One difference however will be a weak disturbance coming around the northeast side of the 500 MB ridge, which will spread cloudiness and maybe some isolated showers into portions of SW VA Monday afternoon.
Otherwise mainly just scattered showers expected overnight as the sfc cold front arrives from the west with pops ranging from only 20-30 pct north of I-96 to about 60 percent along I-94. MUCAPE values will likely stay in the 1,000 - 2,000 J/KG range tonight along and ahead of an advancing cold front. There is a small chance for few showers and storms on Tuesday with a weak warm front in the area.