Aikyam-Lab/Synoptic-Bench huggingface dataset:
115 PM PDT Tue Aug 20 2019 High pressure aloft will bring hot weather to the valleys and deserts through tomorrow.
Given good radiational cooling tonight, favored the cooler edge of the 12 UTC guidance suite with widespread lows in the 40s across western and central North Dakota. Another dry and sunny day is expected on Wednesday with high temperatures in the 70s, which is a bit below normal values in the lower to mid 80s.
351 PM CDT Tue Aug 20 2019 Tonight and Wednesday: Isolated convection from this afternoon will diminish this evening, with dry weather expected overnight as upper level ridging remains across the region. Lows tonight will generally be in the lower to middle 70s.
Current temperatures are comparable yesterday at this hour, however with sunny skies and slightly drier air in place, we should still come out a few degrees warmer than yesterdays high temperatures across the region.
520 PM MDT Tue Aug 20 2019 Hot and dry conditions remain the main story under high pressure across much of the forecast area. Some moisture is keeping afternoon precipitation chances in the forecast near the high elevations along the Continental Divide and the central San Juans.
Upper level ridge continues to spin over the southern plains with some monsoonal influence helping to maintain mid and upper level moisture. The upper level ridge of high pressure will continue to broaden with its axis south and west of the region by Wednesday.
12Z upper air analysis shows a trof axis at multiple levels from the Appalachians stretching southwest over the central Gulf coast. At the surface, a weakly defined pressure trof has migrated slowly northward over the I-65 corridor today where visible satellite imagery animations and radar loops continue to show a cyclonic motion to cloud/precipitation elements around the trof axis. Going into the evening, ensembles of the high resolution models show a rapid decrease in coverage. Overnight lows mostly in the lower to mid 70s.
1024 PM EDT Tue Aug 20 2019 Water vapor imagery highlights a weakness in the mid-upper level ridging across the western North Atlantic. The low-level subtropical ridge reaches west across northern Florida. Undulations in the easterlies along the southern flank of the low-level ridge appear to be forming in- situ within a region of favored ascent over the Bahamas. The first of these inverted troughs pushed west through the Keys last night, the second is forming southeast of Andros.
High pressure will keep southeast winds in place for the next several days, although the sea breeze will turn winds onshore near the coast each afternoon.
A stray shower is possible over the coastal waters but would likely push northward, staying offshore, due to the mean low level ridge axis centered near to the GA/FL state line. Mid to upper level debris clouds from aftn convection should thin out slowly overnight and min temps tonight fairly close to average in the lower to mid 70s and winds light and variable. Slightly less convection should enable temps to warm slightly above today's values into the lower 90s.
Instability will remain on Wed, but lapse rates are expected to weaken (either from being worked over by Tue storms or from advection of warmer air aloft). So, although thunderstorms can be expected ahead of a swd-advancing cold front, potential for strong updrafts is diminished by Wed afternoon. A cold front will advance toward the region on Thu, and greatest rain chances shift swd with the boundary. As high pressure builds in behind the front amid a broad upper-level trough in the ern CONUS, and dry air erodes any low-level moisture, a seasonal end to the week is anticipated, with little humidity and minimal rain chances.
Unfortunately, this will make tomorrow's convection very outflow-dependent, which will make things a little less predictable, but with temperatures expected to reach the low to mid 90s again tomorrow, there should be plenty of energy on which to feed. Look for Heat Index values in the low 100s west of I-65 in the afternoon, as well.
Dewpoints in the upper 70s and lower 80s coupled with mid- to late-afternoon temperatures in the lower 90s, coupled with light winds are creating AppT in the 105-109 range.
A frontal boundary ahead of approaching high pressure has now worked its way through the entire area, with the center of the high still up in Canada. The high will continue to slowly sink southward tonight through Wednesday night, keeping conditions mainly dry. Lows on Wednesday night will be in the lower to mid 50s. The period begins with an area of high pressure to the east and a low pressure to the west.
Clustering cu DUJ-PHD may also suggest a few storms could develop in this region through early evening as the trough approaches. Instability will remain on Wed, but lapse rates are expected to weaken (either from being worked over by Tue storms or from advection of warmer air aloft). So, although thunderstorms can be expected ahead of a swd-advancing cold front, potential for strong updrafts is diminished by Wed afternoon. A cold front will advance toward the region on Thu, and greatest rain chances shift swd with the boundary. As high pressure builds in behind the front amid a broad upper-level trough in the ern CONUS, and dry air erodes any low-level moisture, a seasonal end to the week is anticipated, with little humidity and minimal rain chances.
717 PM EDT Tue Aug 20 2019 High pressure in the Atlantic will direct a moist south flow into the forecast area through the rest of the workweek. Then, an upper-level low will cross the Northeast pushing a cold front towards the Southeast over the weekend. Mid-Upper low still evident on satellite and radar imagery over upstate SC. One area of rain closer to the center of the low has moved out of the CWA to the north. Otherwise, mostly cloudy skies will prevail overnight with lows only dropping into the lower to mid 70s. The upper low will lift northward and away from the area on Wednesday. The low-level flow will shift to the southwest, so while it will still be moist and unstable, the better moisture will be near the coast.
415 PM CDT Tue Aug 20 2019 Skies will partially clear early tonight behind today's thunderstorm complex, however an approaching cold front from the north will bring another chance of thunderstorms Wednesday, although the severe weather threat will be much lower.
Chattanooga Airport, TN 73 91 73 91 / 30 40 40 60 Knoxville McGhee Tyson Airport, TN 71 90 72 89 / 30 40 40 70 Oak Ridge, TN 72 90 72 90 / 30 40 40 70 Tri Cities Airport, TN 66 88 68 86 / 30 40 40 70.
Expect VFR conditions to continue across the Rio Grande Valley through the next 24 hours as the 500mb subtropical ridge across northern Mexico extending into the northern and central portions of Texas continues to provide subsidence across southwest and deep south Texas. The good news is that some weakness will develop in the 500mb subtropical ridge across deep south Texas and northeast Mexico tonight into Wednesday as a 500mb inverted trough moves across the Bay of Campeche Wed afternoon.
Forrester Previous Discussion: A ridge will keep the area dry on Wednesday with highs warming to the upper 80s for Wednesday afternoon.
321 PM MDT Tue Aug 20 2019 Hot and dry conditions remain the main story under high pressure across much of the forecast area. Some moisture is keeping afternoon precipitation chances in the foreceast near the high elevations along the Continental Divide and the central San Juans.
A cooler, drier airmass with northerly flow will allow temperatures to drop into the upper 40s and lower 50s tonight as skies clear across west central MN. No precipitation expected, and highs should be well below seasonal averages in the low to mid 70s. 12Z Thu - 00Z Sat Upper level trough over the western Great Lakes exits the area. Upper level ridge will move across the area this period.
Temperatures behind the outflow boundary have cooled abruptly from the low to middle 90s into the lower 70s. Jonesboro is cooler now at 73 degrees then they were at Sunrise this morning at 76. Expect a repeat tomorrow as the upper ridge remains over the Southern Plains and dewpoints pool ahead of an approaching cold front.
An upper level trough continues to push into the PacNW this afternoon which will keep our afternoon temperatures slightly below average. Current readings across the region appear to be quite pleasant if you like summer weather with the Valley ranging from the mid 70s to the mid 80s while the mountains span the upper 60s to the low 80s. Come Wednesday, temperatures will begin to warm mid- week as the trough shifts east and high pressure strengthens.
759 PM CDT Tue Aug 20 2019 Skies will partially clear early tonight behind today's thunderstorm complex, however an approaching cold front from the north will bring another chance of thunderstorms Wednesday, although the severe weather threat will be much lower.
635 PM CDT Tue Aug 20 2019 Skies will partially clear early tonight behind today's thunderstorm complex, however an approaching cold front from the north will bring another chance of thunderstorms Wednesday, although the severe weather threat will be much lower.
Anticipate gusty wind for the area beginning late Wednesday afternoon as a trough approaches.
/22/ Prior discussion below: Tonight and Wednesday: Isolated convection from this afternoon will diminish this evening, with dry weather expected overnight as upper level ridging remains across the region. Lows tonight will generally be in the lower to middle 70s.
Warmer temperatures are expected across the interior for the end of the week. A few mid/high level clouds are beginning to spread into the region ahead of an upper trough which is poised to move inland over the Pacific Northwest on Wednesday. The trough will quickly depart Wednesday night, leaving the area beneath quasi-zonal flow on the northern periphery of a subtropical Pacific ridge during the end of the week. Expect interior temperatures to gradually trend upward during this time as heights slowly rise and 850 mb temps increase from the mid to upper teens into the low 20s C.
/22/ Tonight and Wednesday: Isolated convection from this afternoon will diminish this evening, with dry weather expected overnight as upper level ridging remains across the region. Lows tonight will generally be in the lower to middle 70s.
Temperatures were in the lower to middle 70s across central and north-central Wisconsin to around 80 across northeast and east-central Wisconsin. For tonight, a cold front will drop south across the area.
High temperatures will cool from the low to mid 70s today to the upper 60s to low 70s Thursday.
Low and mid-level ridge axis will remain across northeast Fl today. Temperatures will be at normal levels with highs in the upper 80s coast to the lower 90s inland.
The upper ridge axis crosses the CWA on Thursday, as a trough moves in from the west.
Each terminal has a chance to experience convection with TLH/DHN/ECP having the highest chance. In the mid to upper levels, the western extension of the Bermuda ridge will gradually build further westward and extend across the GOMEX. While the upper level ridging will bring warmer temperatures and somewhat drier conditions to our area by Thursday, there will continue to be ample moisture for diurnal convection just not as widespread and heavy as we've seen the past several days. Highs will be in the low 90s and lows will be in the low 70s.
all this in part to strong moisture transport in combination with isentropic upglide atop a cold front stretching across southern NE then along the IA/MO border.
High pressure will nose in from the west this afternoon and evening, and thus expect continued clearing ahead of a cold front across the upper Midwest. KMD 220 AM CDT Expect conditions to trend drier and cooler into the end of the work week, as high pressure builds across the region. With this high in place, any precip development into this weekend will stay well west/southwest of the area. At this time, it does appear that DPA and RFD will have the higher chance for observing the lowest ceilings and vis in fog this morning.
The upper level ridge, albeit not quite as strong, will remain anchored over the region today resulting in another hot and dry afternoon across West Central Texas.
1108 PM EDT Tue Aug 20 2019 A cold front will drop south through the region Wednesday with a chance of showers and thunderstorms, especially south of Route 24.
Initial batch of clouds will be moving rapidly at about 40 kts over the Sierra zones thru midnight while another batch of clouds will follow on its heels overnite and on Wed as the upper trof moves across the region. JHM An upper level trough continues to push into the PacNW this afternoon which will keep our afternoon temperatures slightly below average. Current readings across the region appear to be quite pleasant if you like summer weather with the Valley ranging from the mid 70s to the mid 80s while the mountains span the upper 60s to the low 80s. Come Wednesday, temperatures will begin to warm mid- week as the trough shifts east and high pressure strengthens.
1201 AM CDT Wed Aug 21 2019 Scattered thunderstorms have developed this afternoon generally along and east of the Highway 65 corridor. Outflow from that MCS along with an advancing cold front (may be one in the same) will then provide a focus for scattered afternoon shower and thunderstorm potential on Wednesday. Highs over most areas should therefore make it into the lower or middle 90s.
It should be another hot day in the upper 80s to lower 90s, but not as hot as yesterday given the cooler start and uncertainty on clouds.
842 PM PDT Tue Aug 20 2019 Not much to speak of tonight, except increasing high clouds in advance of an approaching cold front. Wind will increase again on Wednesday with gusts 15 to 30 kts possible in the afternoon and evening as a cold front crosses the area from west to east.
The mid level (H5) ridge that has brought the dangerous heat will begin to break down today, as part of an overall pattern change that will bring a deep upper trough down over the Great Lakes and a cool front south down the Plains. Much of the area except for the higher terrain will see heat indices between 105 and 110 today. The lower Ark River valley in west central Arkansas, an area notorious for holding on to higher dewpoints into the heat of the day, will see 110 to 115 heat indices and thus an upgrade to a warning was done this morning.
1201 AM CDT Wed Aug 21 2019 Skies will partially clear early tonight behind today's thunderstorm complex, however an approaching cold front from the north will bring another chance of thunderstorms Wednesday, although the severe weather threat will be much lower.
The exception would be the far southwestern portion of the CWA which was still in the low 80s. This area had decent elevated CAPE values and the low level jet was beginning to develop into the area.
High pressure over the region will result in continued warm and dry conditions Wednesday before a slight cooling trend is expected for late week. A mean longwave ridge is in place this evening across the Rocky Mountain through Great Plains region, with an upper low over the Pacific Northwest coast. After another very warm day tomorrow, temperatures are expected to cool a bit by Thursday across northern Utah behind a weak cold front. Otherwise, with winds turning more westerly/northwesterly with the ridge position shifting west of the area, dry air will remain in place into the weekend.
1230 AM CDT Wed Aug 21 2019 Under the ridge look for VFR conditions and light SE wind to continue.
Still, most of our weather will be impacted by the elongated ridge of high pressure at the surface, set up from north central Canada all the way through ND and eastern SD. This ridge will push east, to the eastern ND/SD border by 00Z Thursday. The 500mb ridge, currently set up from the 4- corners area up through WY/MT/Alberta/Saskatchewan, will shift across the Northern Plains through Manitoba Thursday afternoon. The period begins with an area of high pressure to the east and a low pressure to the west.
Upper level ridge continues to spin over the southern plains with some monsoonal influence helping to maintain mid and upper level moisture.
While some models have suggested slightly less moisture and perhaps a bit more SW flow at the low levels for tomorrow afternoon, not confident enough to leave out any mention of POPs.
424 AM EDT Wed Aug 21 2019 A cold front will drop south through the region today with a chance of showers and thunderstorms, mainly south of Route 24.
Temperatures behind the outflow boundary have cooled abruptly from the low to middle 90s into the lower 70s. Jonesboro is cooler now at 73 degrees then they were at Sunrise this morning at 76. Expect a repeat tomorrow as the upper ridge remains over the Southern Plains and dewpoints pool ahead of an approaching cold front. Increased chances for showers and thunderstorms will occur Thursday through the weekend as the cold front slowly moves into the area and stalls out.
A pair of cold fronts will push southeast through the state late Wednesday into early Thursday bringing additional storms and then cooler and much less humid air will that will last into the weekend. Diurnal convection has died out across central PA after an active afternoon and evening over especially the Lower Susquehanna River Valley. Look for refreshingly cooler max temps Thursday ranging from the low to mid 70s over the Northern Mtns to the L-M 80s in the Susq Valley.
Broad high pressure covers the southern U. from California to Texas with the main ridgeline resting over the central and northern Rockies. An upper trough will approach the area Thursday afternoon, causing surface winds to increase, especially over northern CO and UT. See the fire weather section below for details Models are disagreeing tonight on how quickly the approaching trough will pass through the northern Rockies and clip northern CO and UT. The NAM12 is a good 6 hours faster than the GFS with the GFS holding the trough and its winds back until Thursday evening. Following the trough passage high pressure will reestablish itself over the southwestern U.
Mid level ridge axis will stretch from the central and eastern Gulf of Mexico eastward into the western Atlantic. PoP chances will be around average with widespread 40% and the highest chances from Madison and Tallahassee northwestward into southeast Alabama at 50%. High temperatures today will be in the lower 90s and heat indices in the lower 100s.
1102 PM PDT Tue Aug 20 2019 Wednesday a cold front will produce gusty winds and a chance for rain. This will initially fall into dry subcloud layers and reinforce the cooling which in conjunction with the push of cooler, maritime air will lead to a robust and short-lived wind burst. The winds may also pick up some dust but with cooler temperatures and higher humidity arriving shortly after the winds. /sb 06Z TAFs: Rich moisture streaming into the region ahead of a Pacific cold front will result in broken to overcast mid and high clouds at or above 10,000 feet AGL. The cold front will move into Central WA 19-21Z and slowly migrate east into KGEG-KPUW-KLWS-KCOE 00-04z. Of greater aviation concern will be strong gusts developing ahead of the cold front.
Atlantic high pressure will allow east/southeasterly flow across the region. Plenty of moisture remains behind the departing trough with the 00Z MFL sounding having a PWAT of 1.
/issued 312 PM CDT Tue Aug 20 2019/ (Tonight and Wednesday) Models this cycle continue to indicate the potential for cooler temperatures. Although temperatures will more than likely remain above those usual for this time in August, lows tonight and highs on Wednesday may be a degree or two cooler than this morning's lows and this afternoon's highs.
Models continue to slowly break down the ridge through the end of the week which will not only help bring high temperatures down a few degrees per day but allow the mid-level moisture plume to shift a bit more east on Wednesday. Late Wednesday into Thursday will also see a weak cold front push into the northern Texas Panhandle with uncertainty on how far south the front will make it.
This was occurring north of the warm front near the Nebraska border and in a area of deep moisture convergence and within the theta-e axis. Expect storms to focus initially across north central and northeast Kansas north of the frontal boundary as the low level jet increases this evening. Locally heavy rainfall will again be a concern with theta-e axis expected to lay west to east north of I-70 this evening and then shifting into east central Kansas and Missouri overnight as the low level jet veers to the west by 12Z Thursday.
203 AM EDT Wed Aug 21 2019 A cold front will drop south through the region today with a chance of showers and thunderstorms, mainly south of Route 24.
322 AM CDT Wed Aug 21 2019 Upper ridging continues over the region today but it will be somewhat flattened by an upper trough moving over the Great Lakes region. This will result in cooler 850 mb temperatures over West Texas and southeast New Mexico which will allow for slightly cooler high temperatures today. Upper troughs continue to move over the northern half of the country on Thursday with westerly flow aloft over West Texas. Temperatures across the area are expected to be slightly cooler than those today.
A cold front will move through early Wednesday morning as a trough of high pressure extends from Canada into the northern plains. An upper low will be parked over Ontario into Thursday.
852 PM PDT Tue Aug 20 2019 Wednesday a cold front will produce gusty winds and a chance for rain. This will initially fall into dry subcloud layers and reinforce the cooling which in conjunction with the push of cooler, maritime air will lead to a robust and short-lived wind burst. The winds may also pick up some dust but with cooler temperatures and higher humidity arriving shortly after the winds. /sb 00Z TAFs: Rich moisture streaming into the region ahead of a Pacific cold front will result in broken to overcast mid and high clouds at or above 10,000 feet AGL. The cold front will move into the Cascades Wednesday afternoon around 18-20Z and slowly eastward toward Moses Lake around 00z. Of greater aviation concern will be gusty west to northwest winds moving out ahead of the cold front Wednesday afternoon 21-03z.
842 PM PDT Tue Aug 20 2019 Not much to speak of tonight, except increasing high clouds in advance of an approaching cold front. Wind will increase again on Wednesday with gusts 15 to 25 kts possible in the afternoon and evening as a cold front crosses the area from west to east.
Latest models are showing that although the center of the low, around which this system is wrapped, is well north of the region, there is now indicated 60 kt jet extending down along the front into Northern California. This front will move through with the upper level trough through the day, spilling over to east of the Cascades in the afternoon. An upper level ridge builds quickly behind the exiting front Thursday, with a thermal trough deepening quickly along the extreme southern Oregon coast. The deepening thermal trough will bring southeast winds to the coast south of Cape Blanco by Thursday afternoon.
Chattanooga Airport, TN 93 73 90 74 / 30 20 50 40 Knoxville McGhee Tyson Airport, TN 92 71 88 72 / 30 20 60 50 Oak Ridge, TN 92 71 88 72 / 30 20 60 50 Tri Cities Airport, TN 88 67 85 67 / 30 30 60 50.
349 AM MDT Wed Aug 21 2019 Upper ridging will help guide warm and dry conditions across northeast Montana today with large scale subsidence over the region. For Thursday, a cold front will sweep across the region, bringing with it increasing chances of showers and thunderstorms.
Otherwise, the subtropical ridge will begin breaking down today and tonight as westerlies begin to shift southward. With the slightly cooler mid level air, vertical totals (near 25) are forecast to be a little more conducive to stronger microburst potential this afternoon. Expect storms to diminish this evening, although outflow from a convective system to our north could move far enough south to maintain the storm threat going well into the evening for locations along/north of the Highway 82 corridor.