Aikyam-Lab/Synoptic-Bench huggingface dataset:
High pressure at the surface will be centered to the southeast through this evening, with ridging extending northwest into SC. High pressure at 500mb will also be centered to the southeast this afternoon and evening.
Cloudy and rainy portions of the eastern CWA will see highs in the low to mid 80s, with sunny skies leading to highs in the mid 90s and heat indices approaching 100 degrees over the west.
The low to mid-level flow will become southwesterly on Friday.
225 PM CDT Thu Aug 27 2020 Upper level high pressure centered just south of the four corners region is in the process of weakening and being suppressed farther to the south. A warm front extends eastward from this low across southern South Dakota very near the Nebraska/South Dakota border. CAM solutions from this morning generally keep most of this activity along or just north of the Nebraska/South Dakota border to the north of the warm front. This makes sense as a plume of very warm mid-level temperatures (15-16C) advects eastward this evening across Nebraska to the south of the warm front which enhances the capping inversion. Flow aloft becomes more west to east across our area this weekend as the upper level high flattens to along the Rio Grande.
High pressure ridge remains to our north will kept mainly southeasterly across our area, but sea breeze is now kicking in shifting winds to the southwest right along the coast.
Further westward a band of numerous showers and storms has been maintained on the periphery of the thicker cirrus shield and in proximity to the mid level trough axis.
No lightning has been detected so far, but isolated thunderstorms along the higher elevations for coastals, the southern Cascades, and far northern Sierra are possible through this evening. Farther temperatures are bit cooler than anticipated due to the cooling that the Delta Breeze brought. Tonight, expect the Delta Breeze to continue as the weak upper level trough passes to our north. Tomorrow, heights will start to rise as it moves eastward, which should bring warmer and above normal temperatures to the region. There will be a renewed chance for high elevation thunderstorms again tomorrow afternoon and evening, but the threat should stay confined to the high elevation Sierra. Ensembles continue to indicate the possibility of a weak upper level low developing off the Bay Area coast this weekend, lowering heights over NorCal and allowing temperatures to cool back to near normal.
Air mass is drier behind this short wave, but California trough sends another piece of energy into northern Nevada tonight. California trough weakens Friday and becomes closed off from the westerlies. Trough will still be in the proximity of western Nevada, but has minimal impact across northern/central NV for the next two days. Dry weather returns except for isolated short lived storms may occur for the highest terrain of eastern NV.
However, a mid level trough extends southwest from Laura into East Texas and the Northwest Gulf providing steering flow to the lower levels.
The low is expected to turn northeastward overnight and continue toward the ENE during the day tomorrow, and this is when we'll start to see our greatest impacts here in Middle Tennessee.
A few showers/thunderstorms have developed with heating this afternoon and the weakening of the upper level ridge over the southeast CONUS. With tropical moisture in place and the further breakdown of the aforementioned ridge, additional scattered showers/thunderstorms are expected to develop with heating on Friday.
Temperatures have dropped only very slowly and dew point temperatures this evening are still in the lower to mid 70s. The high and mid level cloudiness will continue overnight with showers moving into the southeast TN Friday morning.
644 PM CDT Thu Aug 27 2020 Upper level high pressure centered just south of the four corners region is in the process of weakening and being suppressed farther to the south. A warm front extends eastward from this low across southern South Dakota very near the Nebraska/South Dakota border. CAM solutions from this morning generally keep most of this activity along or just north of the Nebraska/South Dakota border to the north of the warm front. This makes sense as a plume of very warm mid-level temperatures (15-16C) advects eastward this evening across Nebraska to the south of the warm front which enhances the capping inversion. Flow aloft becomes more west to east across our area this weekend as the upper level high flattens to along the Rio Grande.
Weak upper trough axis has moved by and air mass has stabilized.
More robust thunderstorm development is expected with peak heating out on the high plains of western North Dakota, where CAPE values are getting up above 1500 J/kg in a narrow band. As a trough of low pressure moves in from the Northern Rockies, the CAMs light up with convection along the trough/cold front. Precip will quickly move off to the east Friday, as high pressure builds in behind the front.
624 PM CDT Thu Aug 27 2020 Heat and humidity will continue through tomorrow, before a cold front pushes south through Illinois Friday night. A few storms could become severe Friday night ahead of the cold front. One more day of high heat is on tap for Friday, with highs in the low 90s north and mid to upper 80s south. A cold front will progress south through our CWA Friday night, as the remnant low pressure center from Laura pass across the tip of southern Illinois. SPC has continued with the Slight Risk north of I-72 and Marginal Risk south of there for the cold frontal passage. A noticeable change in air mass is on tap behind that Friday night cold front.
/issued 137 PM CDT Thu Aug 27 2020/ Upper ridge was centered near the 4 Corners region this morning as hurricane Laura moved up through LA. As the remains move NE Friday look for the ridge to expand across the region.
1037 PM EDT Thu Aug 27 2020 Deep layer ridging prevails across the Florida Keys, corroborated by rising heights at all SGL on the 00Z KKEY RAOB. A weak inverted trough over the Yucatan should aid in the tightening gradient overnight, and locations across the Straits of Florida may increase to 10 to 15 knots. The forecast calls for only slight rain/thunder chances overnight, which is in-line with the statistical guidance and the relatively limited moisture in the lower levels.
Expect lows to be mainly in the low 70s across the region.
high temperatures tomorrow are projected to reach the low 90s over roughly the southwestern half of the state.
522 PM EDT Thu Aug 27 2020 A few showers/thunderstorms have developed with heating this afternoon and the weakening of the upper level ridge over the southeast CONUS. With tropical moisture in place and the further breakdown of the aforementioned ridge, additional scattered showers/thunderstorms are expected to develop with heating on Friday.
A ridge builds in from the east and helps to push the stalled boundary back into the CWA.
A cold front sliding southeastward across the region later this afternoon could bring isolated to perhaps scattered showers and thunderstorms, mainly along and east of a line from Britton to Redfield. When the period opens, high pressure at the surface and aloft, is over the region and slowly migrating east out of the region.
The remnants of Hurricane Laura will pass well north of the Carolinas on Saturday dragging a cold front through the area. Ridge of high pressure continues to dominate the weather for the next 36 hours across the region blocking moisture remains in place across GA/SC. The positioning of the ridge will keep abundant moisture from entering the region. With high temperatures in the low to mid 90s and dew points in the 70s, heat indices will be the main concern with values near to 100. Models show decent mid to upper trough with vort center from Laura tracking across NC/VA. Drier air will move across the area from west to east late Sat into Sat night as cold front progresses eastward with a change in air mass for the latter half of the weekend.
Cooler weather will return this weekend. High pressure nosing into the area from the southeast will allow the hot weather to continue through Friday. There is a frontal boundary to the north across central Michigan, while Hurricane Laura continues to make its way northward through the lower Mississippi Valley. The biggest threat is wind, as is usual, but cannot rule out the possibility of hail or even a brief tornado, especially near the warm front over lower Michigan where shear will be better. The cold front is not expected to come through until after sunset, so instability will be on the decrease, but models are in pretty good agreement that a line of storms with gusty winds will come through after 9 PM EDT.
Surface observations placed a low pressure over eastern SD with a cold front moving into western SD. As cooler and drier air moves into the CWA early this morning, TSRA should gradually diminish as midlevel lapse rates stabilize.
By Friday afternoon, a cold front will be moving southward across Nebraska in association with a mid-level trough over the Upper Midwest. Friday evening and overnight, the aforementioned cold front will move southward through the area. Despite weak convergence along the front and an unstable airmass, neutral to slightly positive height tendencies will keep the lift necessary for thunderstorm development on the low side during the evening. Confidence in this occurring is also on the lower end, but if storms do occur there may be enough CAPE and shear for some marginally severe hail or wind. Temperatures behind the front will be notably cooler, with highs in the low to mid 80s.
Temperatures will be noticeably cooler this afternoon with highs in the upper 70s north of I-90 to upper 80s across NW Iowa.
On Saturday, a dry cold front will increase the pressure gradient leading to gusty winds in the afternoon and evening.
417 AM EDT Fri Aug 28 2020 Upper level and surface ridging will remain in control of the region today with remnants of Hurricane Laura moving through the region Saturday.
230 AM EDT Fri Aug 28 2020 Showers and thunderstorms are on tap again today, and cloud cover may keep it much cooler than the past few days.
We could see some showers linger and/or develop into the afternoon as forcing from the upper trough currently moving into northwest North Dakota works through the area. Otherwise, high pressure will build into the region tonight and Saturday, with cooler and drier conditions expected across the area.
Strong gusty winds behind the cold front will continue to maintain breezy conditions through early Friday. A cold front with gusty NW winds expected at all the terminals lasting overnight and diminishing a bit by Friday afternoon.
Atmospheric thickness will increase today, as the remnants of Laura depart to the east and a cold frontal zone approaches from the north. Given warm air aloft and lack of upper forcing, thinking chances will hold off until after dark generally along and north of I-70, with chances gradually increasing after about 10 PM tonight in response to cooler air aloft approaching from the north.
214 AM EDT Fri Aug 28 2020 Ridging will remain in control of the region through Friday with the remnants of Hurricane Laura moving through on Saturday.
357 AM CDT Fri Aug 28 2020 A surface cold front will push through the forecast area today bringing a small chance for showers and thunderstorms. Ahead of the front, temperatures in the 90s and dewpoints in the lower to mid 70s should lead to moderate instability across the area by peak heating. A cooler and welcome pattern change is expected for the remainder of the weekend bringing cooler temperatures to the area.
With the higher CAPE and shear values toward central WI, storms are expected to continue to develop through the morning hours.
AMA will see VFR conditions persist through the period with southerly winds generally AOB 15kts until the end of the period when they start to swing northwesterly with a cold front.
Cold front associated with 500 mb short wave moving thru Manitoba will enter DVL basin 12z-15z and move southeast thru the area during the day. Pops in the fcst have the high pops ending in the southern fcst area by 14z then 20-30 pops ahead of the cold front. High pressure will move into E ND late tonight and east on Saturday. Warm temperatures will begin the period as the upper ridge is in place over the area. and return flow drags the warmer air into the Dakotas ahead of a cold front.
333 AM CDT Fri Aug 28 2020 At 08Z, an outflow boundary was dropping south through the central Sandhills as the main cold front was dropping southeast through the northwest Sandhills. Temperatures remained in the low to mid 70s ahead of the front, with lower 60s reported across the northern panhandle. Today, an upper trough will move into the western Great Lakes. Will keep a slight chance for showers across the far northeast until mid-morning, which will be just ahead of an advancing cold front and 700mb trough passage. the cold front will clear eastern counties by late morning. Highs will be noticeably cooler in the lower to mid 80s, with upper 80s across the southwest. Much cooler lows from the upper 40s to lower 50s north to mid 50s south.
Meanwhile further north, a cold front draped across the Northern Plains will advance southeastward, triggering scattered strong to severe storms later this afternoon and evening. The cold front will reach I-72 by dawn Saturday, then will exit into the Ohio River Valley by midday. Once the front passes, a cooler and less humid airmass will settle southward into the area as highs only reach the lower 80s and dewpoints drop into the upper 50s/lower 60s across the northern half of the CWA by Saturday afternoon.
The upper air pattern consists of an upper ridge centered over west Texas and New Mexico, while an exiting TD Laura moves through northern Arkansas and the mid MS Valley today, eventually the OH Valley and off the mid Atlantic coast. Temperatures will likely get a few degrees warmer today than yesterday, and along with the forecast HI values will get close to our Heat Advisory criteria mainly across the eastern half of the cwa.
Thunderstorm chances pick up late today through early Saturday morning as ridging aloft breaks down across the Western High Plains. Near the surface, a prevailing southeasterly upslope flow will reinforce pooled moisture ahead of the approaching frontal boundary with surface dewpoints generally up into the lower/mid 60s(F), providing sufficient instability with SBCAPE values in excess of 1000 to 1500 J/kg. Look for lows well down into the 60s(F) tonight as cooler air filters into western Kansas in wake of the frontal passage.
Temperatures may cool off a bit on the weekend as a cold front passes. California trough splits with a weak closed upper low descending slowly down the coast, and the mid-latitude westerlies crossing the northern Great Basin through Saturday.
(Today and tonight) Westerly flow at 850 mb this morning will bring very warm low- level air from the High Plains east into the area today. The highest temperature at Oklahoma City so far this summer has been 97, and we are forecasting 100 this afternoon. Tonight, a cold front will approach northwest Oklahoma with some potential for showers and storms near the front late tonight.
412 AM EDT Fri Aug 28 2020 Ridging will remain in control of the region today with the remnants of Hurricane Laura impacting portions of north Georgia on Saturday. Isolated showers developing across portions of west and north Georgia will increase mainly along and north of I-85 this morning will increase throughout the day as the remnants of Laura moves through with the highest POPs across north Georgia this afternoon and evening, where QPF values of 1-2 inches rainfall is expected through the forecast period.
High pressure in the mid and upper levels remains dominant along the TX/Mexico border while a mid-level shear axis over the coastline is allowing for some isolated convection mainly in the middle and upper TX coast.
An upper low over northeast AR will open up as it lifts east northeastward into the Ohio Valley. At the surface, the subtropical ridge axis will continue to extend westward through the central Gulf from the western Atlantic.
It will be kept south of the area by a crossing cold front that will eventually merge with the remnants late Saturday.
Temperatures have dropped only very slowly and dew point temperatures this evening are still in the lower to mid 70s. Chattanooga Airport, TN 87 74 87 72 87 / 70 80 70 30 30 Knoxville McGhee Tyson Airport, TN 89 73 85 69 85 / 40 90 70 40 20 Oak Ridge, TN 88 72 85 68 85 / 50 90 70 30 20 Tri Cities Airport, TN 88 70 81 65 81 / 50 90 100 50 10.
Early Saturday morning thunderstorms and a cold front could impact KPVW. Tomorrow the upper high to our west will start migrating eastward becoming situated overhead. An upper-level high remains over the southwestern CONUS with Hurricane Laura over the Ark-La-Tex and a weak upper low west of Laura. As these features move to the northeast and east respectively, the upper high to the west will expand east and flatten, bringing westerly winds to the forecast area for the weekend. As the high expands east, 1000 mb - 500 mb thickness will increase, bringing another round of high temperatures ranging from 100 - 108 degrees F this weekend. A trough currently over the Gulf of Alaska will begin dipping south late this weekend, bringing some cold air with it.
Highs in the lower to mid 90s, with hottest temps over eastern zones where convection will more delayed than locations further west.
A few showers/thunderstorms have developed with heating this afternoon and the weakening of the upper level ridge over the southeast CONUS. With tropical moisture in place and the further breakdown of the aforementioned ridge, additional scattered showers/thunderstorms are expected to develop with heating on Friday. However, a cold front will be following on its heels and will drop southeast across the area on Saturday. The front should be exiting the area by Saturday evening, with cooler/less humid/drier weather moving into the area for the second half of the weekend.
1238 AM CDT Fri Aug 28 2020 Upper level high pressure centered just south of the four corners region is in the process of weakening and being suppressed farther to the south. A warm front extends eastward from this low across southern South Dakota very near the Nebraska/South Dakota border. CAM solutions from this morning generally keep most of this activity along or just north of the Nebraska/South Dakota border to the north of the warm front. This makes sense as a plume of very warm mid-level temperatures (15-16C) advects eastward this evening across Nebraska to the south of the warm front which enhances the capping inversion. Flow aloft becomes more west to east across our area this weekend as the upper level high flattens to along the Rio Grande. Cooler Saturday compared to lately with highs around 80 or so.
Simultaneously a cold front will be moving southward towards the FA. High pressure extends from the Caribbean Sea into northern Mexico and into the desert southwest.
248 AM EDT Fri Aug 28 2020 Showers and thunderstorms are on tap again today, and cloud cover may keep it much cooler than the past few days.
Temperatures are much cooler where these storms have occurred/behind the outflow, with Clinton and Sedalia both at 73 degrees as of 230 PM. Warm again tomorrow with high temperatures in the low 90s for most locations. A cold front will move through the region from northwest to southeast tomorrow late afternoon through evening. High temperatures for Saturday will be considerably cooler (low to mid 80s) with cooler air coming into the region behind the front.
435 AM CDT Fri Aug 28 2020 (Today and Tonight) Tropical Depression Laura, currently over Arkansas, will push off to the east-northeast today, while an upper level ridge over the Four Corners region moves east into our region. In the low-levels, the 850 mb thermal ridge will strengthen further today, with 850 mb temperatures reaching 27-31 C. Meanwhile, at the surface, we'll continue to see southerly flow due to surface ridging to our east and low pressure over the Texas Panhandle. Sunny skies, the strong thermal ridge, and the warm south winds will result in the hottest day of the week occurring today, with highs of 101-107 degrees.
A surface cold front will push through the forecast area today bringing a small chance for showers and thunderstorms. Ahead of the front, temperatures in the 90s and dewpoints in the lower to mid 70s should lead to moderate instability across the area by peak heating. A cooler and welcome pattern change is expected for the remainder of the weekend bringing cooler temperatures to the area.
750 AM EDT Fri Aug 28 2020 Aviation -Showers and thunderstorms through this morning -Another more potent round of storms through Friday night -Cooler trends through weekend --Showers and thunderstorms through this morning-- Scattered showers and isolated thunderstorms continue to traverse the region along and north of the I 96 corridor early Friday morning. These showers and storms are sparking off a warm frontal boundary that is draped east to west across the region. Following the boundary and the corresponding warm front will be a cold frontal boundary that will move through the region Friday night into Saturday. --Cooler trends through weekend-- Temperatures will cool down behind the front Saturday. The chance of storms will end with a cold front this evening after about 03 to 06 Z, but MVFR to IFR ceilings may set in by 12 Z Saturday.
/Issued 412 AM EDT Fri Aug 28 2020/ Ridging will remain in control of the region today with the remnants of Hurricane Laura impacting portions of north Georgia on Saturday. Isolated showers developing across portions of west and north Georgia will increase mainly along and north of I-85 this morning will increase throughout the day as the remnants of Laura moves through with the highest POPs across north Georgia this afternoon and evening, where QPF values of 1-2 inches rainfall is expected through the forecast period.
Early Saturday morning thunderstorms and a cold front could impact KPVW. Simultaneously a cold front will be moving southward towards the FA. High pressure extends from the Caribbean Sea into northern Mexico and into the desert southwest.
Any lowered visibility or ceiling conditions will quickly improve once the sun rises with the vast majority of the lowered ceilings dissipating by mid morning as the lower atmosphere begins to warm.
/issued 435 AM CDT Fri Aug 28 2020/ (Today and Tonight) Tropical Depression Laura, currently over Arkansas, will push off to the east-northeast today, while an upper level ridge over the Four Corners region moves east into our region. In the low-levels, the 850 mb thermal ridge will strengthen further today, with 850 mb temperatures reaching 27-31 C. Meanwhile, at the surface, we'll continue to see southerly flow due to surface ridging to our east and low pressure over the Texas Panhandle. Sunny skies, the strong thermal ridge, and the warm south winds will result in the hottest day of the week occurring today, with highs of 101-107 degrees.
632 AM CDT Fri Aug 28 2020 At 08Z, an outflow boundary was dropping south through the central Sandhills as the main cold front was dropping southeast through the northwest Sandhills. Temperatures remained in the low to mid 70s ahead of the front, with lower 60s reported across the northern panhandle. Today, an upper trough will move into the western Great Lakes. Will keep a slight chance for showers across the far northeast until mid-morning, which will be just ahead of an advancing cold front and 700mb trough passage. the cold front will clear eastern counties by late morning. Highs will be noticeably cooler in the lower to mid 80s, with upper 80s across the southwest. Much cooler lows from the upper 40s to lower 50s north to mid 50s south.
645 AM EDT Fri Aug 28 2020 Upper level and surface ridging will remain in control of the region today with remnants of Hurricane Laura moving through the region Saturday.