Aikyam-Lab/Synoptic-Bench huggingface dataset:
Thereafter, Laura moves around the periphery of an upper ridge centered off the southeast CONUS, moving in to southwest Arkansas during the afternoon Thursday where it will gradually degenerate into a depression.
The low level flow will shift back to southerly to southeasterly overnight.
442 PM EDT Wed Aug 26 2020 Ridging at the surface and aloft will reside over the southeast CONUS during the short term period, with the JKL forecast area being on the periphery. Hurricane Laura will move north around the periphery of the ridging, with what's left of it reaching AR by the end of the period. The ridging will be weakening overall with time. However, the weakening ridge could make way for some showers/thunderstorms to develop on Thursday afternoon/evening, with the possible aid of a weak wave aloft traveling around the edge of the ridge.
A cold front will stall out late Thursday in South Dakota and possibly extend into parts of Nebraska.
The swell should slowly decrease late tonight into Thursday, but with surf heights remaining around 5 feet through late tonight, we will opt to extend the High Surf Advisory through 4 AM CDT.
226 PM CDT Wed Aug 26 2020 Things remain quiet tonight and tomorrow across the West Texas region as an upper high remains to our west with hurricane Laura moving onshore along the TX/LA state line. Laura will move off to the northeast allowing for the expansion of the ridge over the southwestern CONUS to the north and east. As the ridge expands, the winds aloft will become northerly, and the 1000-500 mb thickness will increase, allowing for a steady increase in temperatures going into the weekend.
1218 PM CDT Wed Aug 26 2020 Currently across the country, mid/upper ridging continues across the central CONUS with subsidence and dry air in place.
1058 AM MDT Wed Aug 26 2020 Upper flow over the northern plains is becoming more zonal as weak energy flattens the ridge. At the surface, low pressure is centered over SD, and a couple of boundaries are draped across the CWA.
Expect gusty outflow winds and areas of blowing dust in the lower deserts.
Synoptically we are sandwiched between ridging to our southeast over the four corners region and troughing over the Pacific Northwest to our northwest. The aforementioned Pacific Northwest trough looks to dig into the northern half of California late on Thursday and could help to scour out a little bit of the smoke and haze, but the only fly in the ointment is that this trough is not very strong and will most likely not get all of the smoke and haze out of the valley.
1000 AM PDT Wed Aug 26 2020 High pressure aloft over the southwest will continue the very h ot conditions in the lower deserts through Thursday.
On Thursday, a surface weak cold front will slowly inch southward with the severe possibility ties to its forcing pushing south.
308 PM EDT Wed Aug 26 2020 Atlantic high pressure will build in from the east, providing warm and humid conditions with occasional showers and thunderstorms through the remainder of the week.
125 PM EDT Wed Aug 26 2020 Hot and mostly dry weather are forecast today as high pressure builds in from the west. This period of wet weather is followed by a couple days of seasonable dry and cooler conditions. After highs within a degree or two of 90 today, overnight lows will only bottom out in the lower 70s given warm advection, moisture increase, and cloud cover. The piece of energy is riding northeastward over a building ridge in the Southeast. Cannot remove PoPs from the forecast completely has rich tropical moisture stream northward around the ridge. This allows a s/w ridge to build up from the south Thursday evening. However, a s/w working across the Great Lakes in the northern stream interacts with a cold front towards 12Z.
Expect periods of gusty winds and heavy rain possible at all terminals with the higher likelihood as you move towards the coast.
- Strong early morning storms Elevated early morning storms were developing north of a warm front from near Ludington southeast to near Lansing. The warm front lifts steadily northeast through the morning so the main action over the next few hours will be for the area to the northeast of a Ludington to Lansing.
Dew points in the 40s are contributing to modest CAPEs to around 500 J/kg over the high plains, approaching 1500 J/kg around Chadron/Alliance as you head into deeper low-level moisture.
No appreciable changes was needed for the late aftn update as east cntrl OH storms continue to form along an ewd sliding warm front. For the overnight, warm front passage will increase the humidity and maintain a shower chance. On Thursday, a surface weak cold front will slowly inch southward with the severe possibility ties to its forcing pushing south.
130 PM PDT Wed Aug 26 2020 High pressure aloft over the southwest will continue the very hot conditions in the lower deserts through Thursday.
A trough axis will approach the area today, producing another round of showers and thunderstorms.
With the upper level ridge centered squarely across the local area today. temperatures will likely near todays highs as the upper level ridge axis will be slow to slide eastward. A small chance of storms sneaks into northern portions of the area Thursday night ahead of an approaching cold front.
The forecast area remains in a favorable location east of the mid/upper level trough axis and within a zone of low level confluence per region VWP data. Furthermore 12z regional soundings sampled high moisture content with the 12z FWD sounding also sampling a seasonably anomalous 50+kt upper jet on the eastern flank of the aforementioned trough axis.
318 PM CDT Wed Aug 26 2020 A weak upper low was located over southwestern Oklahoma per recent water vapor imagery with scattered convection to its east. Will continue with slightly cooler highs in southeast areas in the deeper moisture, which keeps heat indices peaking in the upper 90s to around 101.
(Thursday Night through Wednesday) Look for a hot and dry forecast through this weekend as an upper level ridge will build across the Southern Plains.
311 PM EDT Wed Aug 26 2020 A warm front will lift northeast through the Ohio Valley tonight as high pressure remains over the southeast United States.
Temperatures will be warm with lows Thursday morning in the low to mid 70s.
/Tonight through Wednesday/ As of 19z the upper level synoptic pattern was defined by broad ridging over much of the conus. At the surface an area of low pressure was centered over MN with attendant warm front draped eastward into the Great Lakes region, and a nearly stationary cold front sloping southwest across SD into WY. The deep mixing has also tapped into drier air off the surface, holding dewpoints in the low to mid 60s. Upper trough is progged to move out of the Pac NW late day Thursday. Increasing ascent ahead of trough axis may erode the cap and promote isolated to scattered thunderstorm development in the vicinity of a slowly sagging cold front located somewhere from southern MN into far northern IA.
Much of the same for this afternoon under the influence of upper level northwest flow and leeside troughing over eastern Colorado.
High pressure at the surface and aloft centered to the southeast will ridge over the region this period. For this evening, weak troughing inland along with instability from diurnal heating will help produce a few showers and storms inland.
Lows will be in the lower 70s with highs in the lower 90s, perhaps some mid 90s (this will depend on amount of mixing).
High resolution model solutions have at times suggested isolated showers / thunderstorms could develop in western parts of the state late this afternoon and evening, but the better chances should arrive later tonight as the low level jet increases and upper wave approaches.
940 PM EDT Wed Aug 26 2020 High pressure ridge extending SE from the Mid Atlantic and Mid Atlantic seaboard to east of the Bahamas will continue to produce an E to ESE flow across ECFL overnight.
The forecast area will see warm and generally dry conditions tomorrow under the influence of high pressure over the Desert Southwest.
Temperatures are still expected to drop after the weekend due to a cold front, but there is uncertainty as to how much things cool off.
Overnight a cold front will begin to move in from the northwest. Temperatures Thursday will hold in the 80s with the cloud cover, precipitation, and cooler air working into the area.
A short wave trough is pushing east through NorCal this afternoon. Quiet weather is then expected for the rest of the week into the weekend as we see an upper level low develop off of the coast of the Bay Area.
Fewer showers and storms will form Thursday and mainly over the mountains on the Idaho side as an upper level trough axis moves through.
705 PM EDT Wed Aug 26 2020 Atlantic high pressure will build in from the east, providing warm and humid conditions with isolated showers and thunderstorms through the remainder of the week.
A weak upper low was located over southwestern Oklahoma per recent water vapor imagery with scattered convection to its east. Will continue with slightly cooler highs in southeast areas in the deeper moisture, which keeps heat indices peaking in the upper 90s to around 101.
Surface and upper high are circulating off to the east, but there is very little activity underway across Middle Tennessee as we head into the evening.
a mid level trof axis is expected to remain just west of the CWA with a continued banded area of warm advection holding from Southeast Oklahoma into Northwest Arkansas.
Instability and shear a more favorable back in this area with cooler temps aloft and as a result a few storms have developed.
/issued 226 PM CDT Wed Aug 26 2020/ Things remain quiet tonight and tomorrow across the West Texas region as an upper high remains to our west with hurricane Laura moving onshore along the TX/LA state line. Laura will move off to the northeast allowing for the expansion of the ridge over the southwestern CONUS to the north and east. As the ridge expands, the winds aloft will become northerly, and the 1000-500 mb thickness will increase, allowing for a steady increase in temperatures going into the weekend.
Otherwise, humidity is increasing from the west and the higher dewpoints will keep overnight lows from dropping off - expect morning readings about 10 degrees above the calculated normals. On Thursday, a surface weak cold front will slowly inch southward with the severe possibility ties to its forcing pushing south.
755 PM EDT Wed Aug 26 2020 Ridging at the surface and aloft will reside over the southeast CONUS during the short term period, with the JKL forecast area being on the periphery. Hurricane Laura will move north around the periphery of the ridging, with what's left of it reaching AR by the end of the period. The ridging will be weakening overall with time. However, the weakening ridge could make way for some showers/thunderstorms to develop on Thursday afternoon/evening, with the possible aid of a weak wave aloft traveling around the edge of the ridge.
Ridging at the surface and aloft will reside over the southeast CONUS during the short term period, with the JKL forecast area being on the periphery. Hurricane Laura will move north around the periphery of the ridging, with what's left of it reaching AR by the end of the period. The ridging will be weakening overall with time. However, the weakening ridge could make way for some showers/thunderstorms to develop on Thursday afternoon/evening, with the possible aid of a weak wave aloft traveling around the edge of the ridge.
High pressure ridge extends over our area providing subsidence which will limit storm coverage tomorrow. Overnight lows will be in the low to mid 70s. Highs tomorrow will be in the low to mid 90s inland and upper 80s along the coast. High pressure at the surface and aloft centered to the southeast will ridge over the region this period. For this evening, weak troughing inland along with instability from diurnal heating will help produce a few showers and storms inland.
An ongoing warm/dry pattern is expected to continue today through tonight as an upper level high remains centered across the Four Corners Region with an associated ridge axis extending northeast into the high plains lee of the northern Colorado Rockies. Southerlies will continue to reinforce a warmer air mass across the high plains of western Kansas today resulting in highs back up into the 90s(F). The long wave pattern will start to shift and break down the ridge across mush of the Rockies due to increased upper level divergence ahead of a trough that will exit the Pacific northwest and nearing the Great Plains.
An ongoing warm/dry pattern is expected to continue today through tonight as an upper level high remains centered across the Four Corners Region with an associated ridge axis extending northeast into the high plains lee of the northern Colorado Rockies. Southerlies will continue to reinforce a warmer air mass across the high plains of western Kansas today resulting in highs back up into the 90s(F). Thunderstorm chances return to western Kansas Friday night and into the weekend as ridging aloft breaks down across the Western High Plains.
Warm and humid conditions with dewpoints in the lower 70s across the area will allow showers and thunderstorms to develop efficiently as this weak disturbance arrives, as well as keep temperatures mild in the low to mid 70s tonight. The highest potential will be in southeast IL during the morning, and from Jacksonville toward Champaign and Danville by afternoon.
235 AM CDT Thu Aug 27 2020 A 500 mb trough axis will remain draped from southwest to northeast this morning from northeastern Oklahoma into central Missouri. Isolated to widely scattered convection appears possible this morning along and north of the I-44 corridor as short term models indicate little capping for elevated parcels beneath that 500 mb trough axis.
Patterson (Issued 351 AM CDT Thu Aug 27 2020) Friday: Additional thunderstorms are expected on Friday as the frontal boundary remains nearly stalled in the area, while low pressure approaches from the west. The afternoon and early evening hours are when the threat for severe storms will likely be highest, given enough heating and resultant instability ahead of the cold front. The cold front should sweep the moisture and instability out of the area by late evening, with mainly dry weather then expected overnight. Certainly expecting the warmest temps in the south and cooler north, but may not have enough of a gradient in the forecast.
Our region will be stuck between the large upper ridge over the Desert Southwest and the subsident side of Laura today which means hot and dry conditions are expected. The pattern doesn't look to change much this weekend, although the ridge will slowly begin to flatten as a trof moves into the Pacific NW early on Sun. The flattening of the ridge will promote a westerly component to our wind profile and push the low-level thermal ridge into the far E CWA Sat-Sun w/more widespread 100F temperatures anticipated. Both ECMWF and GFS show the aforementioned shrtwv trof diving sewd into the Southern Plains by Tue-Wed. This trof will drag a cold front into the area on Tue.
100 AM EDT Thu Aug 27 2020 Atlantic high pressure will build in from the east, providing warm and humid conditions with isolated showers and thunderstorms through the remainder of the week.
As Laura continues to track north today, high pressure will limit the amount of synoptic lift. Despite increasing cloudiness today, high temperatures are expected to rise into the lower 90s with afternoon dewpoints in the mid 70s.
While cloud cover, and a weakening of the heights and thicknesses over the area as a result of that weak upper low, may result in temperatures a degree or two cooler this afternoon, the humidity will have increased. Dewpoints are in the lower 70s in places early this morning and expect to see dewpoints remain in the low to mid 70s today due to persistent light southerly flow. This will push a cold front southward through Iowa and into northern Missouri tomorrow evening.
to the lower 90s along/north of a Rushville to Bloomington line where mostly sunny skies will be observed. Any convection will rapidly dissipate toward sunset, followed by mostly dry/warm conditions with lows in the lower to middle 70s tonight. the remnants of Hurricane Laura approaching from the south and a cold front draped across the Northern Plains/Upper Midwest. Meanwhile further north, a line of strong to severe thunderstorms will develop in advance of the cold front across northeastern Iowa into southern Wisconsin by late afternoon.
329 AM EDT Thu Aug 27 2020 An outflow boundary which emanated from the archipelago of Cuba early this evening, is arcing and now approaching the Lower Keys, to 5 to 30 nm south of the Middle Keys near 15 knots.
As Hurricane Laura makes landfall and moves northward through Louisiana and Arkansas, the predominant flow pattern through the low and mid levels will become southerly to southeasterly through the day Thursday. Temperatures are expected to climb into the low 90s on Thursday, and lows will drop to the mid 70s.
The highest wind speed impacts are expected near KSHV and eastern terminals.
252 AM EDT Thu Aug 27 2020 Atlantic high pressure will build in from the east, providing warm and humid conditions with isolated showers and thunderstorms through the remainder of the week.
Additional clearing is likely to take place for a few more hours, further supporting the lowering of forecast mins. Ridging at the surface and aloft will reside over the southeast CONUS during the short term period, with the JKL forecast area being on the periphery. Hurricane Laura will move north around the periphery of the ridging, with what's left of it reaching AR by the end of the period. The ridging will be weakening overall with time. However, the weakening ridge could make way for some showers/thunderstorms to develop on Thursday afternoon/evening, with the possible aid of a weak wave aloft traveling around the edge of the ridge.
Temperatures are a mix today, warmer in a few spots NE and a maybe a degree lower in others.
342 AM CDT Thu Aug 27 2020 At 08Z, an upper trough extended off the coast of central CA north through the Pacific Northwest. A weak frontal boundary extended from near Bridgeport through Thedford and O'Neill. Skies had become clear across most of western Nebraska with temperatures from the low 60s to low 70s. As a disturbance moves into the western Dakotas, a cold front will move through northeast Wyoming into the western Black Hills. A cold front will push southeastward through the western half of the forecast area by late tonight. Friday, the cold front will clear eastern counties by late morning. A northerly breeze 15 to 25 mph across the area and highs will be at least 10 degrees cooler in the lower to mid 80s, with upper 80s far southwest.
Regarding water levels, most of the coastal tide gages in coastal Terrebonne Parish over to Grand Isle and Plaquemines Parish had still not risen to the levels of the high tide from earlier today, however the storm surge water levels are expected to rise as the next high tide approaches overnight into early Thursday morning.
255 AM EDT Thu Aug 27 2020 Hot and humid this afternoon with heat indices in the low to mid 90s. Cooler weather will return this weekend. Focus tonight expected to shift up into srn WI ewd through cntrl MI co-aligned with more substantial theta-e ridging invof frontal boundary. Better combined low level focus/moisture flux looks to develop east through OH Fri aftn yet with substantial low level theta-e ridge in place locally along with some intrusion of stronger flow aloft should support sct aftn storms. Otherwise late arriving cold front and storms expected overnight Friday followed by post frontal drying/clearing/cooling Sat and whittled back Sat am shower chances far se. Sfc ridging follows Sun with pleasant cool/dry wx ahead of weak/washing incoming cold front late Mon.
VFR to prevail through the period at all sites as high pressure dominates, with the exception of possible morning MVFR fog. CDG Chattanooga Airport, TN 91 74 87 74 86 / 20 20 50 70 80 Knoxville McGhee Tyson Airport, TN 91 74 88 73 82 / 20 10 40 70 80 Oak Ridge, TN 91 73 88 73 82 / 20 10 50 80 80 Tri Cities Airport, TN 89 70 87 71 80 / 30 10 50 70 70.
216 AM EDT Thu Aug 27 2020 Atlantic high pressure will persist through Friday, then a cold front will stall over the area this weekend. A deep layered ridge will prevail on Thursday, resulting in a typical summer day. High temps will be in the low/mid 90s with heat indices topping out in the 105-108F range. High temps will again be in the low to mid 90s.
347 AM EDT Thu Aug 27 2020 Hot and muggy conditions will characterize the forecast today as the state remains under the influence of the upper ridge. A few isolated showers and thunderstorms will still be possible, primarily in the western and northern periphery of the forecast area where ridging is slightly weaker. Given the very humid conditions and high temperatures largely in the lower 90s, heat index values will range from the upper 90s to just over 100 degrees. By tomorrow morning, the ridge will begin to retreat, and the flow will become southwesterly across the forecast area. The higher severe threat appears to remain to our west and northwest during the day Friday where more appreciable shear associated with Laura will increase.
324 AM EDT Thu Aug 27 2020 Synopsis/Discussion/Marine/Hydro - Risk for severe weather and flooding into Friday night - Considerable cool down this weekend - Risk for severe weather and flooding into Friday night For much of today the region will be under speed divergence as the low level jet pulls off to the east. For Friday into Friday night the low level baroclinic zone remains over the CWA as an upper wave drops in from the northwest. - Considerable cool down this weekend Northerly winds behind the departing storm advect a cooler airmass down into the CWA for this weekend.
Eastern areas will be more influenced by the ridge and have lower coverage with PoPs in the 20-30% range. Daytime highs will be near to slightly above average in the lower to mid 90s.
A few sprinkles/showers developed in northeast NE just ahead of the cold front, but they will likely diminish within the next hour, although it's important to note that no model accurately depicted that. A cold front will stall out late Thursday in South Dakota and possibly extend into parts of Nebraska.
In general, expect wetter and cooler conditions than we have been seeing.
A weak upper low was located over southwestern Oklahoma per recent water vapor imagery with scattered convection to its east. Will continue with slightly cooler highs in southeast areas in the deeper moisture, which keeps heat indices peaking in the upper 90s to around 101. The Pacific Northwest wave remains on track to pass well north Friday and bring a modest cold front through the area late Friday and Friday night.
High temperatures on Friday should be drastically cooler with readings mostly in the 70s.
202 AM EDT Thu Aug 27 2020 An deep layered ridge will remain across the region through Friday.
High pressure is building in across the local area. The ridge axis will shift south for Friday, with winds transitioning through the day from SE to SW. Scattered to numerous showers and storms are expected with the highest chances more inland. Highs will be in the lower 90s with lows in the mid 70s to around 80.
Arcing high pressure extending from Bermuda to the central states then toward Baja is undergoing bifurcation with the weakness associated with T. The combination of the expanding upper-level ridge and subsidence along the western periphery of Major Hurricane Laura will enhance low-level vertical mixing beneath the subsidence layera aloft. Storms should initiate off the higher terrain of eastern New Mexico and gradually drift eastward, with the best chances for measurable precipitation confined to the northwestern South Plains and the western areas of the extreme southern Texas Panhandle. By mid-week, a longwave trough will pivot across the central CONUS with a 500 mb vorticity lobe rotating across the Intermountain West.