Aikyam-Lab/Synoptic-Bench huggingface dataset:
Upper level RAP analysis places the area between two main areas of high pressure aloft, one in the southwest US and the other extending from the GoM into the western Atlantic. A low was noted riding atop the ridge to the west across the Rockies. Highs today will rise into the low 80s to near 90. DGS Chattanooga Airport, TN 89 74 86 73 89 / 60 40 90 70 70 Knoxville McGhee Tyson Airport, TN 89 72 85 72 86 / 70 30 80 80 70 Oak Ridge, TN 89 73 85 72 86 / 60 30 90 80 80 Tri Cities Airport, TN 88 69 85 70 84 / 40 40 80 80 80.
442 PM EDT Wed Jul 29 2020 Dry weather is expected for most areas today, though shower and thunderstorm chances return near and north of I 80 this afternoon with a weak cold front. Periodic rain chances are then expected through the weekend under a trough of low pressure.
This previous mentioned wave and developing low pressure along with the nearby boundary will be the catalyst for showers and thunderstorms Thursday. The guidance has struggled some on the placement of these features thus far leaving exact placement of the higher rainfall totals in question.
This seems very reasonable given the forecasted cold frontal position by then.
337 PM EDT Wed Jul 29 2020 Weak surface cold front currently approaching the M59 corridor will continue slowly southward to about the Ohio border around sunset.
114 PM EDT Wed Jul 29 2020 Dry weather is expected for most areas today, though shower and thunderstorm chances return near and north of I 80 this afternoon with a weak cold front. Periodic rain chances are then expected through the weekend under a trough of low pressure.
1219 PM CDT Wed Jul 29 2020 At 2 AM, a cold front was located over southern Clayton and Fayette counties in northeast Iowa, and the southern half of Grant County in southwest Wisconsin. Low temperatures on Thursday morning will range from the lower 50s to mid-60s. Weak high pressure will dominate through the remainder of the work week with dry weather, seasonable temps and some morning fog in favored valley/low-lying areas. Over the weekend, northwest flow will amplify as deeper troughing spreads into the Great Lakes.
Deep layer ridge across the Gulf progged to flex a bit to the W/NW tomorrow, resulting in an intrusion of relatively lower PWAT air (around 1. Consequently, very little chance of rain is in the forecast for tomorrow, with temperatures rising into the lower and perhaps mid 90s under a mix of clouds and sun. Regarding potential tropical cyclone nine in the Caribbean Sea, the aforementioned longwave trof digging into the NW Gulf Coast region makes it unlikely this system will have any impact on our area. 13 High pressure will continue to ridge across the Gulf waters maintaining light west to southwest winds through the weekend.
Highs will be a few degrees cooler tomorrow as NE flow begins to ramp up. Dry conditions still expected Thu night through at least early Sat given dry/stable NE flow building over the area due to strong ridge over the northern Lakes. Southern stream trough then lifts into the Ohio Valley late Sat and there are still substantial differences among 12Z guidance regarding exact track and resulting precip chances/timing late Sat through Mon. Much depends on evolution of next high- latitude trough digging through Canada late this week and here again the drier Canadian and ECMWF solutions are preferred which indicate southern stream wave largely missing us (though to be fair deterministic GFS only grazes our eastern zones) with best precip chances tied to northern stream trough arriving Mon (which the GFS indicates but is likely too aggressive).
1029 AM CDT Wed Jul 29 2020 High pressure will shift farther east of the region today, allowing warm and increasingly humid air to spread in from the southwest. 06z surface map placed weak high pressure over northern KY. The cold front that pushed through the area early yesterday morning, had turned stationary from the southern tip of IN back into central MO. Highs should top out in the upper 80s to around 90, and dewpoints creeping into the lower 70s from the southwest will push afternoon heat indices into the mid 90s over the western half of the area. Fairly muggy conditions overnight with lows only dropping into the lower 70s.
119 PM CDT Wed Jul 29 2020 High pressure will shift farther east of the region today, allowing warm and increasingly humid air to spread in from the southwest. 06z surface map placed weak high pressure over northern KY. The cold front that pushed through the area early yesterday morning, had turned stationary from the southern tip of IN back into central MO. Highs should top out in the upper 80s to around 90, and dewpoints creeping into the lower 70s from the southwest will push afternoon heat indices into the mid 90s over the western half of the area. Fairly muggy conditions overnight with lows only dropping into the lower 70s.
349 PM CDT Wed Jul 29 2020 At 2 PM CDT, a warm front extended across northwest South Dakota into eastern Montana. An upper low centered across west central South Dakota will remain a source of some instability across southwest North Dakota, and along with southeast upslope flow will provide some low level convergence/lift for convection this afternoon and evening. As the upper low drifts to the southeast tonight, there will be some h500 height rises across western North Dakota which should limit the convection tonight and Thursday morning. An approaching h500 trough Thursday afternoon should bring a cold front into the picture and for that we will add pops back in across the west, although the chances will spread east Thursday night.
Temperatures will be cooler on Thursday with highs in the mid 80s to near 90 degrees.
Water vapor imagery continues to show an upper low centered over western Nebraska and South Dakota, and is aided by strong moisture transport in the lower levels to produce very efficient rainfall in the scattered showers and storms across the CWA.
Drier tomorrow as upper ridge has better grasp, and highs will be slightly higher than the past few days, and humidity will elevate the heat index into the triple digits for most of the area.
The high clouds are streaming from a system over the eastern Rockies and western SD. That system will track southeast across the central Plains and lower Mississippi Valley through Thursday night due to the trough over the Upper Midwest and Great Lakes.
While heavy rain is a possibility due to slow movement of the system, still some uncertainty of the location of any potential excessive rainfall, but with LLJ focused into the southwest corner of the state, this area probably has the highest chances of seeing heavy pcpn.
Farther south, convection is hard to come by as the influence of the upper ridge axes, one to our west and another extending westward along the Gulf coast states, is helping to limit convective development thus far today so have trimmed back PoPs across our southern zones through the remainder of today.
Thicker sky cover is also expected to keep highs in the low to mid 80s today. the biggest difference by tomorrow will be from a weak low-level jet along the southern Tennessee border from a weak trough through the OH/TN river valleys. Lows tomorrow morning in the low 70s with highs in the mid 80s.
High pressure will bring hot and dry conditions through the upcoming weekend. With the ridge building in across the region today there is very little overall concern.
341 PM EDT Wed Jul 29 2020 High impact weather potential: None Pattern synopsis/forecast: Deep northwest flow continues across the Great Lakes, courtesy of mid and upper level troughing slowly rotating across northeast NOAM. Not much of a surface response with these waves, with the area largely dominated by expansive high pressure which spans from the Canadian Prairies southeast into the northern Great Lakes. Not a whole lot of change in the coming days as upper level troughing will only slowly work its way east. Definitely gonna be a bit cooler tonight as Canadian originated airmass centers further overhead, with lows by sunrise Thursday mostly in the 50s. perhaps a few degrees warmer near Saginaw Bay once again.
We then turn our attention westward to the main midlevel trough across western NE, which is aiding in thunderstorm development across the High Plains.
1123 AM MDT Wed Jul 29 2020 Water vapor shows upper low over northern WY/southern MT with copious amounts of moisture extending through the Northern Plains. At the surface, trof extends from central MT through the NEB panhandle. Upper low will drift slowly southeast today into the Black Hills. Main upper low shifts southeast through the Central Plains on Thursday, but enough moisture/instability in place for additional convection especially from the Black Hill through southwest SD.
A short wave trough aloft moves out of the Wyoming Rockies and over the central High Plains region tonight.
High pressure remains across the region with easterly wind flow remaining in place. With the drier air, temperatures will be in the low to mid 90s with heat indices into the triple digits again on Thursday.
With continued troughing in place tomorrow providing forcing for ascent as well as abnormally high moisture levels, scattered showers and thunderstorms will increase once more Thursday afternoon and will provide another opportunity for locally heavy rainfall (WPC again has most of the region within a slight risk for excessive rainfall).
Winds continue from the east and southeast thanks to a persistent low level ridge that remains parked just to our north. The low level ridge combined with dry air pushing through will continue to suppress rain chances and cap them at 10 percent or less. Thereafter, we continue to monitor Potential Tropical Cyclone Nine, which may impact our area. The disturbance currently remains disorganized with no well- defined center of circulation, and as a result the forecast track and intensity is significantly more uncertain than is typically the case for more organized tropical cyclones.
No significant changes to the forecast as the weather pattern features a persistent Pacific trough to the west and a high-pressure ridge to the east.
A short wave trough over the central High Plains will translate southeast over the next few days while the subtropical ridge retreats westward, thus placing west Texas and southeastern New Mexico under northerly flow aloft.
257 PM CDT Wed Jul 29 2020 Beautiful conditions continue through the rest of today as high pressure dominates the area. Light southerly winds develop late Thursday as high pressure slides east ahead of an approaching cold front.
547 PM MDT Wed Jul 29 2020 Water vapor shows an upper low spinning right over the BLKHLS with radar indicating showers/thunderstorms likewise rotating around the BLKHLS. Given the high precipitable water and weak mean wind, heavy rains and flash flooding will continue to be a threat through this evening, and possibly into early Thursday. However, it does appear that the upper low will shift southeast a little on Thursday, with precipitable water dropping as well.
While heavy rain is a possibility due to slow movement of the system, still some uncertainty of the location of any potential excessive rainfall, but with the LLJ focused into the southwest corner of the state, this area probably has the highest chances of seeing heavy pcpn.
Issued by National Weather Service Wilmington NC 1015 PM EDT Wed Jul 29 2020 The area will remain between high pressure to the southeast and a trough of low pressure inland through this weekend. Evening scattered convection is winding down, and the remainder of the night should be rain free in most areas and quite mild with lows ranging from the lower to mid 70s well away from the coast to the upper 70s near the coast. The region will remain between a broad upper trough over the eastern U. and deep layer ridge to the southeast.
Short wave ridging remains in place today and that is bringing another hot afternoon to NorCal. Current temperatures are running similar to a few degrees warmer than yesterday and we should see Valley highs top out near to just above the century mark. Our short wave ridge will be replaced by a short wave trough that will clip the northwest part of the state tomorrow. This short wave trough will get phased into the long wave trough off of the PacNW as the four corners high amplifies during the day Thursday.
High pressure will bring hot and dry conditions through the upcoming weekend.
Several vorticity maxima are passing around a mid-level trough, which continues to support the showers and thunderstorms across the area. MRB A short wave trough over the eastern Plains has turned the low level flow around to the southwest. The 850mb gradient tightens substantially through the evening as this occurs which ramps up the low level jet and subsequently the moisture convergence. With mass fields showing the stronger forcing further south, I think the highest rainfall amounts will generally be across the eastern Ozarks, along and south of I-44 much like what the RAP is depicting. The primary area of low level moisture convergence moves east slowly through Thursday morning as the low level circulation stretches out. With the low level forcing moving away, the showers and storms should become less widespread through the day.
655 PM CDT Wed Jul 29 2020 A short wave trough over the eastern Plains has turned the low level flow around to the southwest. The 850mb gradient tightens substantially through the evening as this occurs which ramps up the low level jet and subsequently the moisture convergence. With mass fields showing the stronger forcing further south, I think the highest rainfall amounts will generally be across the eastern Ozarks, along and south of I-44 much like what the RAP is depicting. The primary area of low level moisture convergence moves east slowly through Thursday morning as the low level circulation stretches out. With the low level forcing moving away, the showers and storms should become less widespread through the day.
Mostly dry conditions overnight as temperatures settle in the low to mid 70s. Afternoon temperatures reach the low 90s, except along the coast where it will be around 90 degrees.
713 PM EDT Wed Jul 29 2020 High impact weather potential: None Pattern synopsis/forecast: Deep northwest flow continues across the Great Lakes, courtesy of mid and upper level troughing slowly rotating across northeast NOAM. Not much of a surface response with these waves, with the area largely dominated by expansive high pressure which spans from the Canadian Prairies southeast into the northern Great Lakes. Not a whole lot of change in the coming days as upper level troughing will only slowly work its way east. Definitely gonna be a bit cooler tonight as Canadian originated airmass centers further overhead, with lows by sunrise Thursday mostly in the 50s. perhaps a few degrees warmer near Saginaw Bay once again.
Overall the current fcst looked pretty good, however did increase pops slightly across the lower I81 corridor where convection continues, as well over the southern Valley. CDG Chattanooga Airport, TN 74 85 72 89 72 / 40 80 60 80 50 Knoxville McGhee Tyson Airport, TN 73 86 72 87 72 / 30 90 80 80 50 Oak Ridge, TN 73 85 72 87 71 / 30 90 80 80 50 Tri Cities Airport, TN 69 85 70 83 68 / 30 90 90 90 40.
732 PM CDT Wed Jul 29 2020 (This evening through Thursday) The main concerns for the short term period are the Slight Risk for severe thunderstorms over NW Oklahoma (including portions of Harper, Woodward, Woods, and Alfalfa Counties) and the Slight Risk for excessive rainfall, especially over northern Oklahoma, in association with a midlevel trough tracking SE from the WY/SD/NE junction.
713 PM EDT Wed Jul 29 2020 Remaining showers and thunderstorms dissipate or settle south of the Ohio border with the cold front during the evening. High pressure gains some traction during Thursday resulting in a more persistent 5-10 knot northerly wind and some standard fair weather cumulus lasting through afternoon. The cold front settling south of the Ohio border brings an end to thunderstorm potential at DTW for tonight. Weak surface cold front currently approaching the M59 corridor will continue slowly southward to about the Ohio border around sunset.
753 PM EDT Wed Jul 29 2020 Dry weather is expected for most areas today, though shower and thunderstorm chances return near and north of I 80 this afternoon with a weak cold front. Periodic rain chances are then expected through the weekend under a trough of low pressure.
Beautiful conditions continue through the rest of today as high pressure dominates the area. Light southerly winds develop late Thursday as high pressure slides east ahead of an approaching cold front.
At 2 PM CDT, a warm front extended across northwest South Dakota into eastern Montana. An upper low centered across west central South Dakota will remain a source of some instability across southwest North Dakota, and along with southeast upslope flow will provide some low level convergence/lift for convection this afternoon and evening. As the upper low drifts to the southeast tonight, there will be some h500 height rises across western North Dakota which should limit the convection tonight and Thursday morning. An approaching h500 trough Thursday afternoon should bring a cold front into the picture and for that we will add pops back in across the west, although the chances will spread east Thursday night.
The leading edge of a robust upper level disturbance by mid summer standards was approaching the high plains this afternoon, along with an associated cold front. The lower levels will likely not be nearly as unstable by this time so that the chance for severe storms is low. Highs Thursday will be held down into the upper 70s in central Kansas, with warmer mid 80s along the Oklahoma state line. The upper level ridge is staying south or west of our area and it looks like this will be the case out through the first week of August.
These conditions will be the result of having the persistent blocking high pressure ridge anchored over the four corners area. Upper air model analysis, in the short-term, has the ridge axis shift slightly westward in response to a weak disturbance riding over the ridge pattern. While the ridge remains anchored over the Southwest, will expect little change in weather conditions. Model maintain their high confidence levels in the continuation of the blocking pattern.
959 PM CDT Wed Jul 29 2020 This evening will continue to be beautiful under the high pressure. Fog should dissipate by morning as the sun warms the lower atmosphere.
416 PM CDT Wed Jul 29 2020 Upper air analysis showed a Bermuda ridge over north central Gulf of Mexico, a short wave over eastern Oklahoma, and a stronger wave over eastern Wyoming.
High pressure will continue to bring dry conditions and above normal temperatures to central and northern Nevada through the weekend.
248 PM PDT Wed Jul 29 2020 A fair amount of cumulus clouds are starting to build over the Cascades and on the higher terrain east and west of the Cascades.
626 PM CDT Wed Jul 29 2020 This evening will continue to be beautiful under the high pressure. Fog should dissipate by morning as the sun warms the lower atmosphere.
723 PM EDT Wed Jul 29 2020 A weak cold front will approach from the Great Lakes tonight and then sag south across Pennsylvania Thursday.
703 PM EDT Wed Jul 29 2020 Currently - A surface through lower level Atlantic ridge extends across Florida into the Gulf of Mexico. Drier lower level air associated with the ridge is also providing a rather inhospitable environment for shower development, despite little to no inhibition. Forecast - Over the next couple of days, ridging will continue to dominate Keys weather. Rain chances will remain slim to none due to the lower level ridging and drier air aloft.
A cold front remained entrenched between the Highway 30 and 20 corridors. E-W frontal boundary currently in our northern cwa will continue to sag slowly southward across the dvn cwa through the day, as high pressure builds into the Upper Midwest. Highs will only be in the upper 70s to lower 80s, which is about 10 degrees cooler than yesterday. Lows will be in the lower 60s at most locations, with some upper 50s in far nw IL.
323 AM EDT Thu Jul 30 2020 Broad mid level ridging will remain stretched across the Gulf of Mexico and Florida Peninsula today and Friday, while the surface based subtropical ridge axis extends from the Atlantic across the Florida Peninsula. This will setup weak low level flow and slightly above normal temperatures, with highs topping out in the low to mid 90s.
309 AM CDT Thu Jul 30 2020 A somewhat weak upper level ridge draped across the Gulf of Mexico to the far western Atlantic Ocean will finally expand far enough north to bring rain chances down considerably across the CWA. A flat trough to the north of the area today will begin to sharpen and track southward across the midwest Friday. Subsidence ahead of this system as well as from ridge over the GOM should finally give us a rain free day (or close to it).
Highs Thursday will be tempered with the clouds and rain with highs in the low to mid 80s. Thursday night the low level just once again develops and will combine an upper level trough that approaches the area to result in more heavy rainfall for the area.
Aloft, light flow, generally out of the WSW and weak ridging across the Gulf states provides some suppression to the afternoon storms, usually quashing most of their longevity. However, tonight, a short wave tops the 500mb ridge to the west, and spokes around the deep low over Hudson Bay/Great Lakes, sustaining some of the showers and thunderstorms, especially across our north through the evening. A ridge has set up nicely on western portion of the CONUS and as a result from that, a trough is beginning to take shape across the midwest and eventually deepening, swinging down to us in the southeast Friday. High temperatures Thursday and Friday across the Delta and central MS will be in the low 90s and combined with humidity, heat indices will be near 105 degrees.
108 AM EDT Thu Jul 30 2020 Periodic rain chances are then expected through the weekend under a trough of low pressure. Scattered showers/isolated thunderstorms mainly N of I 80 near a weak sfc cold front should wane overnight with the loss of instability, and exiting upper level support. Areas south and southeast of PIT should continue to see shower and thunderstorm chances Thursday night and Friday with this area in close proximity to the weak cold front, and where better upper support is progged. Dry weather should return to the north of this area as high pressure begins to build in.
This is plausible given rich moisture and 300MB trough slowly moving across the area during the day. Precipitation chances should wane Thursday night with loss of heating and passage of trough, but a trailing trough will approach on Friday, which should enhance lift Friday-Friday night. End of precipitation Friday-Friday night will be a race between drier air filtering in and the timing of the trailing trough. On Thursday, temperatures will likely be suppressed in the north with extensive clouds and rain, but some breaks and warmer air (sans MCS) will tentatively go warmer in the south. Cooler air will keep temperatures near 80 areawide on Friday.
Temperatures will be cooler on Thursday with highs in the mid 80s to near 90 degrees. Temperatures will be a little cooler Thursday night with lows Friday morning in the low to mid 70s. The cold front will move into the Mid-South on Friday and remain over the region for much of the weekend.
Afternoon high temperatures yesterday generally ranged in the 101 to 105 degree range across the SJ Valley due to the influence of the desert southwest ridge. Similarly hot conditions are expected to occur again today as the ridge remains the dominant weather feature over Central California.