Aikyam-Lab/Synoptic-Bench huggingface dataset:
The surface cold front is aligned from northwest Indiana, to southern Illinois, and eventually down across eastern Arkansas. Plenty of convection is occurring well ahead of the cold front, with abundant moisture advecting into the Mississippi Valley with falling heights aloft. Showers and scattered thunderstorms will continue to fill in across eastern Kentucky through tonight as the cold front and upper level trough axis approaches from the northwest. Mostly clear skies will reign Sunday night, as high pressure builds in from the west.
Surface analysis has a high pressure system to the northwest of the forecast area. With the high pressure the current clouds will dissipate as the sun goes down tonight.
Expect rounds of showers and scattered storms to continue through tonight until the approaching cold front passes through the region late tonight. For Sunday, a much more pleasant airmass and partly cloudy skies await us behind the cold front.
Showers and thunderstorms continued in close proximity to a weak cold front/surface boundary sagging south over Central Texas and an MCV over the I-35 corridor between San Antonio and Austin. The main focus of the rain and flooding will be along the I-35 corridor into the Hill Country with the highest potential in the San Antonio area to parts of the Austin area.
/issued 331 AM CDT SAT AUG 20 2016/ Another afternoon of showers and thunderstorms expected today as high pressure to the east and a weak cold front to the north allow for ample moisture to flow in from the Gulf.
with AZ between high pressure over N. CA/NV and the pinched remnants of elongated low pressure to the south.
High Pressure will return by mid week allowing for for a modest warming trend.
221 PM MDT SAT AUG 20 2016 Water vapor imagery shows upper trough exiting the nrn plains as it pushes into the upper Midwest. Upper ridging dominates the wrn CONUS.
216 PM EDT Sat Aug 20 2016 A cold front will bring better rain chances tonight into Sunday. Rain chances increase tonight as a pre-frontal mid-level trough moves up the Ohio Valley. Models indicate that convection along this trough axis will be decreasing as it enters our western counties late this evening. Still, with moisture and lift increasing ahead of the cold front, a gradual increase to likely PoPs was maintained. The cold front will arrive in the pre-dawn hours. TAx The 500 mb trough axis will push through Sunday night.
This was triggered by an upper short wave system moving through the region, while the expected cold front has only made progress to far northwestern AR at this time. The upper level low pressure trough is deepening in the eastern Plains at this time and will help the movement southeast of the cold front.
(Issued 903 AM CDT SAT AUG 20 2016) The 14Z surface analysis shows a deepening cyclone centered over the western Great Lakes region, with its cold front extending from west of Chicago to near Tulsa Oklahoma. On the other hand, a typically broad ridge remains anchored over the Caribbean and Bahamas with a large area of southerly flow spread over the central Gulf states. Not surprisingly, extensive stratus persists over most if not all of the Tennessee Valley, and showers are already noted over parts of northwest Alabama and larger portions of west Tennessee ahead of the cold front. Model soundings may be a little overly aggressive with CAPE if the clouds fail to break, and with minimal low-level shear and relatively weak winds through the lowest 20kft, heavy rain still appears to be the primary storm threat today.
225 PM CDT SAT AUG 20 2016 A cold front is moving south through the northern Permian Basin this afternoon, preceded by an outflow boundary/prefrontal trough which is near the Pecos River. Showers and thunderstorms have been slow to develop, but with heating this afternoon, and the arrival of the front, it appears widely scattered showers and storms will be possible over most of the Permian Basin with better chances over the higher terrain where upslope flow will increase the next 6 hours. A fairly strong upper level trough, at least for August, over the midwest this afternoon will translate eastward.
255 PM EDT SAT AUG 20 2016 An upper level ridge will extend from the Atlantic westward into the Gulf of Mexico through Sunday. Temperatures will remain above normal ahead of an approaching cold front.
201 PM EDT SAT AUG 20 2016 A strong cold front will move through the forecast area early Sunday morning. High pressure will build over the region for the start of the week. Through 6 pm best chances for shower/thunderstorms will be across the I-75 corridor as a prefrontal trough arrives. Warm air advection will occur today in advance of an approaching cold front. Dew points in the lower 70s will creep northward into the county warning area.
252 PM EDT Sat Aug 20 2016 Weak high pressure will continue to drift east from the Mid- Atlantic coast through tonight. A cold front over northern Illinois will move through the central Mid-Atlantic Sunday afternoon into the evening.
250 PM EDT SAT AUG 20 2016 Showers have been very isolated this afternoon, widely separated in the Gulf waters north of the Lower Keys and in the Straits well south of the Middle Keys. A weak but broad area of high pressure to our north is keeping the flow light to gentle, and mainly from the east or southeast.
Expect few showers and storm late this afternoon with the higher pops mainly in the western counties for the remainder of the afternoon. Abundant sunshine will keep temperatures a few degrees warmer today.
Anticipate the remainder of the day to be dry with showers associated with the main upper level low over North Dakota now looking to remain to our north. A surface warm front does lift into the Missouri River Valley late this afternoon, and a couple of CAMs try spit out some convective development over south central SD during this time frame. The warm front continues to lift northward tonight, and it will be a milder night with lows in the lower to mid 60s. Early in the forecast, broad mid-lvl ridging continues to dominate the central US.
Low to mid level moisture will remain over the forecast through tomorrow aided by an upper low spinning over Southeast Texas. We should have a little better chance of showers and thunderstorms over a wider area tomorrow accompanied by slightly cooler afternoon temperatures in the upper 80s to around 90.
A few showers and storms may also continue across SE OK near a mid to upper shear axis associated with the mid to upper low near east TX. Over the next several days, at least some diurnal convection is expected as we remain on the fringe of the upper ridge and a mid to upper trough to our west only slowly progresses east out of the southern Rockies. The highest PoPs will remain west of I35 and mainly across NW OK in association with this feature. By late in the week, chances will decrease as the ridge tries to move over the Southern Plains but with abundant moisture remaining in place and our region remaining near the northern fringe of the ridge, suspect at least SCHC PoPs each afternoon for a portion of our CWA.
137 PM CDT SAT AUG 27 2016 Upper ridge remains over the SE US with a broad trough extending from the Dakotas down across Utah. This trough will pinch off leaving a cut off low over the 4 Corners region. This low is expected to be pulled NE around the top of the ridge. Also have an upper low along the TX coast hang around for a few days.
A little warmer tonight with slightly more low- level moisture than last night and less effective radiational cooling.
Weak frontal boundary and low pressure expected to drift across the area in the next 24 hours. weak convergence and lift and continued slow erosion of the lower clouds on the edges of the earlier widespread low stratus and fog. Minimums tonight will be a bit warmer than last night in the central and south and should range from the lower 60s north to the mid to upper 60s in the south.
Upper level analysis shows trough axis over the eastern Dakotas. Weak ridging is in place over the Rockies, with an upper low over the southwest US. Winds will be south to southeast, perhaps a bit breezy at times overnight from the Pine Ridge through south central SD.
154 PM EDT SAT AUG 27 2016 A large ridge of high pressure will reside over Pennsylvania through the weekend bringing very warm and mainly dry weather.
258 PM EDT SAT AUG 27 2016 High pressure will build across the region this evening then move to the east Sunday.
255 PM EDT SAT AUG 27 2016 Mainly clear to partly cloudy skies are expected under high pressure tonight. A weak cold front will bring scattered showers and thunderstorms into the region Sunday afternoon and evening.
1015 AM MST SAT AUG 27 2016 A unusually strong low pressure system for this time of year will move across northern Arizona today and Sunday, where shower and thunderstorm activity will be most widespread. The low pressure system will move eastward by late Sunday setting up a mostly dry and warm week. The upper level trof axis is forecast to move into the 4 corners area by Sunday evening so there is still a threat for a few afternoon and evening mountain storms over southern Gila County where monsoon moisture will continue to be a little deeper.
With the coastal trough/low along the northern Texas coast, a bit more suppression has developed across South Texas with little convection developing. Continue to keep highest pops trimmed mainly to the east including the northern Coastal Bend and Victoria Crossroads as well as the middle Texas coastal waters due to proximity of the trough/low and availability of moisture. Through Sunday, the trough/low will slide farther south along the coast, increasing POPs for Sunday, more so Sunday night. As for temperatures, kept cooler temperatures across the northeast accounting for the extra cloud coverage and better chances for rain, with temperatures in the upper 80s although this may still be too warm.
422 PM CDT Sat Aug 27 2016 Convection is continuing to fire up over the NW edge of the Gulf of Mexico, associated with an upper level low moving in from the east. Moist inflow dewpoints at the surface are in the lower 70s, and this saturation continues up to 850mb where dewpoints are around 15 degrees.
212 PM EDT SAT AUG 27 2016 High pressure over the Great Lakes and Ohio valley will drift east today. This will allow low pressure to track east across the northern Great Lakes into Ontario on Sunday dragging a cold front across the region.
with lows in the lower 70s in the far southeast and in the metro areas of especially Columbus and Cincinnati. Kept overnight lows a little warmer than short term guidance. The mid/upper level ridge again dominates the weather for Sunday in especially the southeast.
214 PM MST SAT AUG 27 2016 A unusually strong low pressure system for this time of year will move across northern Arizona today and Sunday, where shower and thunderstorm activity will be most widespread. The low pressure system will move eastward by late Sunday setting up a mostly dry and warm week. Upper level low still remains northwest of our area this afternoon. The dry air on the southern periphery of the low is mixing down, reflected in surface dew point values in the 30s and 40s roughly along and south of I-10. For the remainder of the week the upper level pattern will continue to favor troughing along the West Coast.
215 PM PDT Sat Aug 27 2016 A strong cold front is expected to bring gusty winds this evening and heighten wildfire concerns.
339 PM EDT SAT AUG 27 2016 High pressure over the area tonight will move east into the Atlantic on Sunday and create a cool onshore breeze over coastal areas. A cold front arriving from the west will bring a chance of showers and thunderstorms Sunday into Sunday night with high pressure building in behind the front through midweek.
The GFS/NAM gradually lift the favorable thermodynamics, tied with a sfc warm front, north during the day Sunday, favoring central MN/northern WI with any pcpn chances. GFS and ECMWF both point to broad ridging to start, giving way to northwest flow for a couple days, then a amplification of the upper level ridge over the plains for the end of the week. Less humid, cooler air should move in post this system for Wed/Thu. With weak gradient flow and a broader passing trough aloft, the lower clouds to persist thru the afternoon into early this evening, with only a gradual slow rise of cig hgts with the diurnal warming/mixing thru the afternoon. Passage of the main mid level trough and the lower level cyclonic circulation should allow for a decrease of clouds this evening.
217 PM EDT SAT AUG 27 2016 Northern MI on the edge of eastern US ridge. Area is in right entrance region of 110kt upper jet which is riding over the top of the ridge. Should continue to see lowering clouds and areas of fog as seen upstream cover the region before the low tracks NE of MI as well. Sunday high pressure moves in scouring out the low clouds in the morning. High pressure will remain centered over the Western Great Lakes region Sunday night.
A low pressure center drifting eastward over northern Arizona will bring cooler than normal daytime temperatures, showers, and thunderstorms through Sunday.
230 PM CDT SAT AUG 27 2016 Convection beginning to develop along moisture axis around the wrn periphery of the upper ridge. In addition, convection associated with the low pressure system along the TX/LA Gulf coast has moved into our srn areas.
102 PM CDT SAT AUG 27 2016 A stationary front over northern Oklahoma was reinforced by convective outflow early this morning, but was beginning to advance slowly northward as a warm front into the southern Kansas counties this afternoon.
342 PM EDT Sat Aug 27 2016 Warm and dry weather can be expected until late Sunday as high pressure slides across the Upper Ohio Valley Region. Large high pressure will continue to keep the region warm and dry through the first half of Sunday. Weak southerly flow will edge dewpoints upward overnight, and in turn, keep lows warmer than average.
The latest satellite imagery was showing a fairly dry WNW flow aloft across the region which was gradually backing with time as a deep low pressure system progressed slowly east through WRN Canada. The models continue to show the flow aloft increasing across the area this afternoon/eve as the low continues to push east across Canada resulting in marginal red flag wind conditions across SE Idaho (more on that in the Fire Weather discussion below).
(Issued 1019 AM CDT SAT AUG 27 2016) High pressure aloft over the VA/NC border remains in control of the weather pattern for much of the Southeast this morning, with E/SE winds in place across much of the region. At the sfc, the center of the high is anchored over the western Carolinas, just west of the parent upper ridge. A bit of weak upper level energy will rotate around the ridge aloft, helping to spark isolated to widely scattered (at best) showers and storms this afternoon, mainly in N/NErn areas of the CWFA.
316 PM EDT SAT AUG 27 2016 Upper level high pressure in place with hot and humid weather through the weekend. With temps already in the lower 90s and heat index values hovering either side of 100. shifting into the Lowlands early this evening. This in association with some deeper moisture advecting in from the SW around the ridge. Upper level ridging overhead continues.
Mid level lapse rates around 7 c/km and 30-40 kts of shear is enough to generate a few strong storms along the upper trough axis as it is moving over northwest MN. along and north of the warm front.
300 PM EDT SAT AUG 27 2016 Hot and muggy weather will continue across eastern Kentucky through the weekend, as the ridge of high pressure that is currently parked over the Ohio, Tennessee, and mid Mississippi valley regions, continues to exert some influence on the region. Another round of showers and storms is expected on Sunday, as the aforementioned ridge weakens and allows height falls to occur over the region. The persistently warm and humid air mass will still be in place, however, and with the ridge weakening, conditions will be bit more favorable for shower and storm formation on Sunday.
Main coastal trough will slide farther south along the coast, increasing rain chances through Sunday.
Still expecting to see upper 80s to low 90s areawide, with convection developing again in the vc of a weak upper low centered along the TX/LA coast.
321 PM CDT SAT AUG 27 2016 A coastal trough has been the instigator of showers and a few thunderstorms across our region, rotating in a counter-clockwise direction.
613 PM EDT SAT AUG 27 2016 High pressure will build across the region this evening then move to the east Sunday.
252 PM EDT SAT AUG 27 2016 The large deep layer ridge centered across the mid Atlantic will gradually weaken and become more east west orientated by the end of the period.
While the synoptic warm front has lifted well to the north into southern Wisconsin, outflow boundaries left behind by early morning convection will likely serve as the focusing mechanisms for additional thunderstorms within this moisture axis later this afternoon and evening. A broad subtropical high pressure ridge will be in the process of building by Sunday evening promoting a storm track to the north of central IL as 500 mb height gradients and stronger westerly flow become confined to the northern tier of states and southern Canada.
Expect coverage of convection to be on the low side.
548 PM EDT Sat Aug 27 2016 Warm and dry weather can be expected until late Sunday as high pressure slides across the Upper Ohio Valley Region. Large high pressure will continue to keep the region warm and dry through the first half of Sunday. Weak southerly flow will edge dewpoints upward overnight, and in turn, keep lows warmer than average.
Strong upper level trough currently moving through the Red River Valley, and with destabilization across the southern counties some severe cells have developed. Later tonight will be quiet as the upper trough moves off into Ontario. However, upper support on Sunday will not nearly be as good with ridging building overhead and only a possible weak embedded vort to set things off. Better chances into Sunday night as low level jet sets up over the eastern CWA and a cold front pushes through Thus just have some low POPs Sunday afternoon with better chances Sunday night.
Sustained west and southwest winds in the teens and 20s will be the norm, with gusts in the high 20s to around 30 mph. The trough passing north of the area will cause temperatures to cool a few degrees for Sunday.
224 PM EDT SAT AUG 27 2016 High pressure builds across the Tri-state area for this weekend.
216 PM MDT SAT AUG 27 2016 SW flow remains in place across the plains with a mid-upper level trough still in place across the desert southwest.
229 PM CDT SAT AUG 27 2016 An upper level high will be found to our east and an upper level trough will be found to our west through this forecast.
75 inches over the lower portion of the Upper Mississippi Valley. A little warmer compared to today - mid 80s on average for E Iowa/NW Illinois and noticeably humid with dewpoints in the lower 70s.
421 PM CDT SAT AUG 27 2016 For the remainder of the afternoon into the early evening, there will continue to be a strong moisture gradient over the forecast area with shower/thunderstorm chances mostly confined to south of the Highway 84 corridor.
302 PM CDT SAT AUG 27 2016 Minor trough in light southwest flow was evident on water vapor imagery from about Dalhart south to Wink and should continue to foster some storm development through the afternoon. Other than a thermal ridge enhancing vertical mixing in the western Panhandle, the surface pattern itself is void of any focus for storms. This thunderstorm threat should amplify on Sunday as a rather impressive upper low draws closer from NW Arizona. Upper level jet energy will remain well north of the area for the first part of the extended as high pressure in the southeastern CONUS attempts to dominate the weather picture out that way. A few weaknesses are noted within the confines of the high most notably a relative low along the middle Texas coast.
1231 PM CDT SAT AUG 27 2016 Updated aviation portion for 18Z TAF issuance Wet over all but north-central Wisconsin today, then more sunshine, warmer, and rather humid on Sunday. The large-scale trough over the Northern Plains will quickly weaken as the bulk of the energy within it shifts off to the northeast. The zonal regime won't last long, as a sharp/fairly deep trough is expected to quickly develop just off the West Coast. But the amplitude/position of the downstream ridge and the next downstream trough remain rather uncertain, and that has considerable impact on the forecast for Wisconsin. Uncertainty increases thereafter as the position/amplitude of the eastern NOAM upper trough are unclear.
346 PM CDT SAT AUG 27 2016 Rather significant upper level trof axis located in the Red River Valley as of late this afternoon will continue to translate eastward across northern Minnesota tonight. There is a very weak west/northwest low level push behind this S/W trof axis Sunday morning, which means that the surface-850 mb temp/moisture gradient will likely get "left behind" and still be lying WNW to ESE across central MN on Sunday. Initially, general large scale synoptic subsidence in the wake of the departing wave may inhibit additional TStorm development, but as low level warm/moist advection increases Sunday afternoon with increasing southwest low level flow, we have retained 25-40 PoPs over the central/south sections of the DLH CWA along and just north of the warm frontal zone.
210 PM MDT SAT AUG 27 2016 SW flow remains in place across the plains with a mid-upper level trough still in place across the desert southwest.
350 PM EDT SAT AUG 27 2016 An upper level ridge will persist over the region through the weekend. Overnight temps in the low-mid 70s. Over the southern coastal plain and the sandhills, modest moisture advection courtesy of an upper level low off the SC coast coupled with afternoon heating should trigger scattered convection. Low temps upper 60s nw to the low/mid 70s se.
For now, will go with more of the low clouds forming than fog but will show some fog, especially in the river valleys. A weak short wave trough is expected to come across the northern sections of Minnesota and Wisconsin. This wave looks to be pretty flat with very little pv advection, but there is some warm air advection in the low levels that generates 2 to 4 ubar/s of up glide on the 305K isentropic surface.
206 PM EDT SAT AUG 27 2016 Mainly clear to partly cloudy skies are expected under high pressure tonight. A weak cold front will bring scattered afternoon showers or thunderstorms into the region Sunday afternoon and evening.
Warm frontal boundary currently located across southern Nebraska is expected to lift northward towards the mid Missouri Valley tonight. Later tonight, with the front lifting northward and the low level jet nosing into the region, isolated to scattered showers and thunderstorms may pop along a narrow area of elevated instability near the Buffalo Ridge area of east central SD and southwest MN. Highs will reach the lower 80s in the east to lower 90s in the west. The upcoming week is mainly characterized by an upper ridge across the plains throughout the week. This will provide relatively mild conditions, but ridge is not strong enough to keep disturbances completely at bay.
436 PM EDT SAT AUG 27 2016 High pressure will continue to move away from the region tonight. This will allow low pressure to track east across the northern Great Lakes into Ontario on Sunday dragging a cold front across the region.
While geopotential heights will gradually rise across the central Plains with weak ridging aloft on Sunday, a moist southerly surface flow and diurnal heating will give rise to an unstable airmass for at least mention of small PoPs again late the day, mainly across far eastern and western parts of central Kansas.
214 PM EDT SAT AUG 27 2016 A large ridge of high pressure will reside over Pennsylvania through midday Sunday bringing very warm and mainly dry weather.
627 PM EDT SAT AUG 27 2016 A large ridge of high pressure will reside over Pennsylvania through midday Sunday bringing very warm and mainly dry weather.