Aikyam-Lab/Synoptic-Bench huggingface dataset:
HIGH PRESSURE SETTLED ACROSS SOUTH TEXAS TODAY WITH VISIBLE IMAGERY REPORTING MOSTLY CLEAR SKIES OVER LAND AND THICK MID LEVEL CLOUDS ACROSS THE GULF WATERS. AS THE HIGH SHIFTS EAST AND A COASTAL TROUGH DEVELOPS ALONG THE SOUTHERN TEXAS COAST WEDNESDAY. MODELS HAVE TRENDED WITH A SLOWER COASTAL TROUGH DEVELOPMENT. TEMPERATURES WILL ALSO TREND SLIGHTLY WARMER.
UPPER LEVEL HIGH OVER CALIFORNIA WILL FLATTEN AS A STORM SYSTEM APPROACHES THE AREA. SHOWERS WILL DIMINISH WEDNESDAY NIGHT AS UPPER LEVEL RIDGING BUILDS.
Hennig (Today through Thursday afternoon) An upper level trough that brought precipitation yesterday will be lifting north today reducing rain chances across the area. The highest PoPs will be in the Big Bend where the mountains will help with convective initiation. Low pressure over the western U. However this continues to be the summer without a strong upper high for our CWA.
The weather looks to become more interesting for the late week periods as the upper trof evolving across the western conus moves over the northern/central Rockies before lifting out across the northern Plains.
An upper level ridge axis from the four corners region to northeast Minnesota along with strong southerly winds will bring near record-breaking temperatures across most of the region with northeast Minnesota seeing upper to mid 90s for today. Near critical fire weather conditions are expected mainly over our Minnesota counties due to low RH values in the low to mid 30s along with winds that will become gusty by early afternoon.
Look for cooler temperatures today and Thursday as well as some showers and isolated thunderstorms, mainly in eastern Nevada. Highs today will be much cooler with readings in the 70s seen across the forecast area. In addition, there will be some afternoon breezes to help make it a feel cooler than it should. With the clearing will come some cooler temperatures. Previous shift issued SPS to cover the possible frost and cooler temperatures and will continue this product as a result. Overnight lows will be in the 30s and 40s, though some of the cooler locales could see the upper 20s.
Thursday appears the most likely day for widespread storms given that the aformentioned trough centers itself across the forecast area.
A cut off upper low will then drift southeast across the region late this week and through the upcoming weekend. Hi-res guidance still supports the idea of localized amounts of around 5 inches where southeast flow is forced to ascend the ridgetops of the Appalachians. Surface ridging and a slightly drier air mass will work into the region late this week. However, a cut off upper low over the eastern Grt Lks is progged to drift southeast toward western Pa, keeping the chance of mainly PM showers in the forecast. Upper level trough will still be over the area through the upcoming weekend, resulting in a daily chance for pop up showers or a few rumbles of thunder.
However, just as quickly heights will start to fall again later today and tonight as the Great Lakes troughing deepens and extends south into the Ohio Valley - along with another batch of mid level energy inbound from the west for Thursday morning. The weak trough axis passes through later Thursday dragging its mid level impulse across the CWA.
We'll continue to be under the influence of ridging aloft with highs in the mid 80s across western Wisconsin and low 90s across Minnesota.
Well below average temperatures will remain the norm today in the wake of a strong cold front that pushed through the area yesterday. The more "newsworthy" (but generally not impactful) concern will be that some of the highest terrain, particularly along the Rocky Mountain Front and into Glacier National Park, may see some snowflakes. Even on the highest terrain, accumulations should be under an inch, so this will only serve as a reminder that the summer is beginning to come to a close here in MT. Looking beyond today, an upper level trough that moved into the area in the wake of yesterday's cold front will be slow to exit the area and will hang around through the day tomorrow, which will result in some isolated to scattered rain showers, mainly during the afternoon and evening.
These storms will be associated with a stalled cold front across nwrn Nebraska. The stalled cold front should be located across wrn Nebraska or the Panhandle and winds aloft at h500-300mb increase to 25-50 kts. A deep -18C 500mb upper low centered over Utah should send perturbations through Colo and WY setting off storms across wrn Nebraska. The NAM suggests the abundance of subtropical moisture aloft and Gulf moisture at the lower levels, would support HP type storms in addition to severe hail and wind threat suggested by SPC. Strong to severe storm activity should continue Thursday evening and perhaps overnight as an upper low moves slowly into WY. The attendant cold front across wrn Nebraska moves slowly east into ncntl Nebraska.
Today Through Thursday Night A mid/upper trough extends from near the Baja Peninsula northeastward to the Great Lakes region and points northeast this morning. Downstream of this trough, a very moist air mass is in place with PWAT values of 2+ inches over roughly the southern half of Arkansas. The mid/upper trough will shift east late this evening into tonight as the western fringe of subtropical ridging begins migrating into the northern Gulf. Despite models suggesting another all day rain scenario on Thursday, do think the presence of upper ridging and subsidence in the wake of the departing trough will suppress activity some locally. Highs today will range from the low/mid 70s in the Ozarks to low/mid 80s elsewhere (upwards of 5 to 10 degrees below average).
It will most certainly feel like a summertime August day outside today with afternoon highs in the lower 90s with heat indices near 100. Greater coverage of storms is anticipated across northwest Alabama along a slow moving trough axis that is just to the west of the forecast area this morning. Thursday appears the most likely day for widespread storms given that the aformentioned trough centers itself across the forecast area.
Have the highest PoPs concentrated across the eastern Concho Valley and Big Country the remainder of the morning and into the afternoon. Will continue with a chance (20-30 percent) of scattered storms overnight, with the highest PoPs across the Big Country.
These temperatures are warmer than this time yesterday. High pressure located across the eastern CONUS was moving east.
Cooler temperatures are also expected through the rest of the week. A few isolated showers have begun to develop over the lower elevations south of the Mogollon Rim. Longwave trough continues to move into the Intermountain West today, with the center of the trough passing over Utah during the day Thursday. Breezy and cooler conditions are expected as a result today and again on Thursday. As the trough passes to the north, the monsoonal moisture in place gets swept away with dryer conditions expected in its wake Thursday and into the weekend.
Otherwise, today looks to be a tad warmer than yesterday with highs reaching the mid 80s on the Plateau and upper 80s to around 90 elsewhere. Although forecast soundings don't show anything to write home about for today, deep layer shear increasing up to 30 knots along with the high PWAT values could allow for a few storms with damaging wet microbursts.
Through Thursday Night: Zonally elongated western Atlantic ridging continues to encompass the southeastern United States, as South Florida remains under the southern periphery of this broad feature. 5 inches, which remains within the lower 10th percentile for moisture this time of year. Temperatures along the interior and Gulf coast portion of the region should be in the low/mid 90s through Wednesday.
A deep trough continues to dig over the Pacific Northwest with a messy pattern over the central CONUS. An upper-level trough axis extending from the great Lakes through the Southern Plains is blocked by the Bermuda High but will begin to gradually shift by late week as the ridge weakens.
302 PM CDT Wed Aug 18 2021 Weak trough across the region coupled with a southwest flow of moisture will continue into Thursday.
(This evening through Thursday) A very slow-moving, or nearly stationary, shear-axis/trough continues to combine with plentiful low level moisture to spark new convection this afternoon from the northern Concho Valley northeastward into the Big Country. With very humid conditions in place, expect lows to continue to be mild, dropping only into the low to mid 70s. Highs should reach into the low to mid 90s in most locations.
154 PM MDT Wed Aug 18 2021 Current surface analysis shows the cold front stretching from southwest North Dakota into eastern Wyoming, sliding eastward through the forecast area as we progress into the afternoon. High pressure rises will bring breezy conditions into the region through today. By Thursday evening, the upper trough begins to slide east of the rockies and associated upper low moves east towards the forecast area.
The western Atlantic ridge is drifting southward and becoming elongated across the Gulf of Mexico. On the other hand, the upper-level trough over the Upper Midwest, which extends southwest through the Ozarks, will begin to eject eastward this afternoon through tomorrow. The base of the trough will move across the Tennessee Valley and will be accompanied by a greater presence of showers and storms, mainly affecting our northwest late this afternoon. Any activity that lingers beyond dark this evening will diminish before midnight with mostly pleasant conditions overnight and temperatures in the lower to mid 70s. Areas south of I-85 will be further away from forcing and under a greater influence from the ridge, so only routine summertime PoPs are expected.
Showers and isolated thunderstorms associated with a slow-moving upper low will develop over the higher terrain this afternoon. Temperatures will be cooler today. Gusty surface winds for most sites along with the potential for showers/thunderstorms over the higher terrain after 18/18Z, including KMYL.
Grace which is well south of the Keys at this time is still influencing our weather as the pressure gradient remains tight and the winds elevated from the second feature which is the high pressure ridge to the north.
240 PM EDT Wed Aug 18 2021 Short Term (Rest of Today - Thursday): High pressure with east to southeasterly winds. Temperatures will be the main concern with high temperatures in the low to mid 90s. Overnight, lows along the east coast will be above normal to near record in the low 80s overnight.
Even with gradient flow starting to tighten up a bit, low level flow remains weak enough for patchy valley fog again tonight, especially on Wisconsin side closer to ridge axis.
Tomorrow will be a competition between deep tropical moisture and upper-level ridging building in from the west. Hi-res models have hinted that upper-level ridging and drier air will mix in by early tomorrow evening, squashing PoPs down to 20 or less by then. Regarding temperatures, upper-level clouds and winds preventing the low-levels from decoupling overnight will make overnight lows hover near 80.
This will likely result in slightly low coverage of showers and thunderstorms today with perhaps the highest chances across areas south of Interstate 10. Otherwise, high temperatures appear to be on track to peak in the high 80s to low 90s most areas. High temperatures Thursday may be slightly warmer than today with highs generally in the low 90s.
Highs are expected to reach the low to mid 90s across most areas and closer to the 100 degree mark across the southwest. As far as precipitation go, limited activity is anticipated as subtropical ridge begins to take control of the area.
1146 AM MDT Wed Aug 18 2021 Current surface map places low over southwest North Dakota with cold front in southeast Montana/northern Wyoming. Cold front slides into western South Dakota this morning. Water vapor showers upper level trof moving into Northern Rockies. Biggest question for today will be eastward progression of the cold front as hi-res/short term guidance has front stalling out along eastern edge of forecast area. Narrow axis of instability along the cold front may support isolated thunderstorms late today. Lead impulse rotates out of upper trof into eastern Wyoming tonight.
An upper level ridge axis from the four corners region to northeast Minnesota along with strong southerly winds will bring near record-breaking temperatures across most of the region with northeast Minnesota seeing lower to mid 90s for today. Near critical fire weather conditions are expected mainly over our Minnesota counties due to low RH values in the low to mid 30s along with winds that will become gusty by early afternoon.
The region remains situated within a broad regime of synoptic ridging that stretches from the Rockies eastward to the Central Atlantic Ocean, with multiple embedded cyclonic perturbations. Lower tropospheric theta-e values nudge slowly higher over the course of the day, reinforcing the warmer and muggier airmass that has been infiltrating the region over the last couple of days.
/issued 1036 AM CDT Wed Aug 18 2021/ Upper-trough continues to support areas of convection mainly across portions of east Texas and Northwest Louisiana this morning. Otherwise, expect temperatures to climb into the low to mid 80s across the cloudy and rain-soaked regions of northeast Texas, southwest Arkansas, and southeast Oklahoma with the lower 90s elsewhere.
In the presence of departing upper low over northern IN and favorable low level instability, have received a few reports of funnel clouds, but the likelihood of any tornadoes is low with negligible deep layer shear. Fair weather should otherwise prevail through the day Thursday as subsidence from building mid/upper heights from approaching upper ridge overspreads the region.
A couple more days of quiet weather are expected while the area remains under weak upper-level ridging.
Currently, an upper ridge stretched southwest over eastern portions of the Southeast. Areas along the I-10 corridor will see MLCapes this afternoon topping out in the 2000-2500J/kg range with a downward tapering to 1000-1500J/kg range as one moves inland to the Highway 84 corridor. Temperatures topping out in the low to mid 90s are expected this afternoon. Best chance of any rowdy storms will be along and north of the Highway 84 corridor. With moisture levels increasing along with upper subsidence, am expecting overnight temperatures to fall into the low to upper 70s, a bit above seasonal norms. This convection is expected to last into the early evening hours, mainly along and north of the Highway 84 corridor.
Deep ridge will remain across the area with hot humid conditions and light winds persisting.
131 PM EDT Wed Aug 18 2021 Several rounds of precipitation are expected to occur across the region through the weekend as the remnants of Fred move east, while an upper trough arrives from the west. Expect high temperatures in the low to mid 80s.
Another round of showers and storms will then be possible overnight as heights lower to our west and the low level jet strengthens, increasing isentropic ascent.
Daily afternoon shower and storm chances continue into the weekend ahead of a cold front. High temperatures on Thursday will be in the upper 70s to mid 80s in the lowlands and upper 60s to low 80s in the mountains.
Warm rain processes, deep layer moisture in place, and a low level jet on the ern side of the low should support heavy rain at times. The rain should taper off from SW to NE this afternoon and early evening as the low completes its passage. An approaching trough should result in scattered to isolated showers and thunderstorms Thursday afternoon, after daytime heating builds instability aloft.
Persistent troughing over the western half of the nation results in positive height anomalies over the GrtLks Rgn and above normal 850 mb temps.
149 PM EDT Wed Aug 18 2021 A weak upper trough and abundant moisture will continue across the region into the latter part of the week and through the weekend. As of 1030 AM EDT Wednesday: Considerably more suppressed this today with diurnally fired garden variety deep convection fcst to be limited to just the high terrain. An upper trof swings across the region and pulls a weak cold front into the NC mtns. This will keep a good chance of shra/tstms across the higher terrain with more isol to sct convec likely over the non/mtns. Soundings show weak shear thru the layer, while sbCAPE values remain in the lower range. A weak upper low will persist across the Oh Valley into Mon and make for deep nw/ly flow aloft and weak forcing.
Afternoon high temperatures will be a bit warmer than yesterday.
249 PM CDT Wed Aug 18 2021 Continued heat and smokey skies today under continued ridging aloft. Little change in this pattern is expected as we head into Wednesday night and Thursday as the upper trough slowly makes its way towards the Upper Midwest.
However, an approaching upper level disturbance currently over north Texas will move northeastward and potentially spark another round of storms late tonight, with the higher chances once again over our southern counties.
Overall it's a much cooler day today with periods of rain expected. Southeast MT will largely be dry and warm today as the greater dynamics associated with the upper low are positioned west of that area.
A cut off upper low will then drift southeast across the region late this week with unsettled conditions through the upcoming weekend. Convection developing within the convergence bands will move north and interact with the warm front where low-level hodograph size should be maximized (250-350 m2/s2 SRH) during afternoon peak heating. It will be warmer with highs in the 75-85F range.
(Today through Thursday afternoon) An upper level trough that brought precipitation yesterday will be lifting north today reducing rain chances across the area. The highest PoPs will be in the Big Bend where the mountains will help with convective initiation. Low pressure over the western U. However this continues to be the summer without a strong upper high for our CWA.
The center of post Tropical Cyclone Fred located across western Pennsylvania will move north tonight into Thursday. High temperatures Thursday will range from the upper 70s in the mountains to the lower 90s in the piedmont.
Strong midlevel cyclone (for August standards, 572-573 dm) will make little progress eastward Thursday, remaining near Salt Lake City through the daylight hours.
Upper ridge off the coast. Persistence with overnight lows in the low to mid 70s. Model ensemble means project an upper trough riding slowly east across the Midwest and into the Mid Atlantic, mainly just to our north and northeast, weakening and suppressing the upper ridge to our W/SW, allowing tropical cyclone Henri offshore to be picked up and lifted to our NE with no expected impact on our FA.
A low pressure system will continue to linger over southern Idaho tonight and then begin to lift to the northeast on Thursday.
Models do show a little further penetration of the cold front across north central SD this evening, perhaps close to KMBG before retreating back to the west during the day Thursday.
High pressure remains centered over the Western Great Lakes this afternoon. High pressure hold over the Western Great Lakes thru Thursday (at least). High impact weather potential: Minimal Synopsis/Forecast: Remnants of Fred are in the process of merging with weak upper level troughiness over the Great Lakes.
However, with a lingering low level jet on the ern side of the low, a few isolated bands could create heavy downpours. An approaching trough should result in scattered to isolated showers and thunderstorms Thursday afternoon.
Cooler temperatures are also expected through the rest of the week. However, storm motions will be to the north-northeast and will be much faster than yesterday given a strong low pressure system entering Idaho. A few isolated showers have begun to develop over the lower elevations south of the Mogollon Rim. Longwave trough continues to move into the Intermountain West today, with the center of the trough passing over Utah during the day Thursday. Breezy and cooler conditions are expected as a result today and again on Thursday. As the trough passes to the north, the monsoonal moisture in place gets swept away with dryer conditions expected in its wake Thursday and into the weekend.
-Kredensor Well below average temperatures will remain the norm today in the wake of a strong cold front that pushed through the area yesterday. The more "newsworthy" (but generally not impactful) concern will be that some of the highest terrain, particularly along the Rocky Mountain Front and into Glacier National Park, may see some snowflakes. Even on the highest terrain, accumulations should be under an inch, so this will only serve as a reminder that the summer is beginning to come to a close here in MT. Looking beyond today, an upper level trough that moved into the area in the wake of yesterday's cold front will be slow to exit the area and will hang around through the day tomorrow, which will result in some isolated to scattered rain showers, mainly during the afternoon and evening.
Ridge aloft will keep dry weather in place along with warm and somewhat humid conditions through Thursday. Normal high temperatures for August are in the lower to mid 80s.
Although the low-level jet will be strongest farther west across the High Plains, southerly low-level flow does increase sufficiently over the forecast area to see some areas of weak to moderate isentropic lift on the 300K-310K surfaces leading to increasing POPs overnight.
Once again, similar conditions expected across the region today as high pressure lingers to the east and a trough stays to the west.
These winds will gradually diminish later this afternoon and into the overnight hours as the low fills and the pressure gradient loosens. Aloft, a western CONUS trough remains in place with an eastern CONUS ridge. The longwave trough will begin sliding towards the area tonight and through the day Thursday. Locations in northwestern North Dakota will likely top out in the upper 60s while those in the southern James River Valley will top out in the low 90s.
Rain chances to diminish on Thursday night as upper-level ridge becomes better established areawide. Otherwise, low temperatures tonight and Thursday night to average in the low to mid 70s with highs on Thursday in the upper 80s to lower 90s.
/issued 240 AM CDT Wed Aug 18 2021/ Much drier air aloft had moved into most of the region early this morning just behind the upper level low pressure trough edging east through the Red River Valley.
Though, broad troughing upstream of Fred, combined with plentiful llvl moisture reflected in dewpoints in the low 70s, has triggered additional showers in Fred's wake. An approaching trough should result in scattered to isolated showers and thunderstorms Thursday afternoon.
The lift and moisture combo will provide for scattered showers and storms across the area this afternoon, with the highest chances along and south of Interstate 44, closer to the better lift. Given the high moisture content, locally heavy rainfall will be possible. Cloud cover and precip will keep highs in the lower to middle 80s across southern Missouri, increasing into the upper 80s across the northern CWA.
307 PM EDT Wed Aug 18 2021 The short term period is overwhelmingly quiet with surface ridging dominating our weather and resulting in mostly clear skies and light southerly winds. If that's the case then high temperatures may be a degree or two warmer than today. A deep trough in the western U. The 500 mb trough that is over the Rockies 12z Sun get ejected out into the northern plains 12z Mon and gets sheared out. Another trough moves into the Pacific NW 12z Mon and into the northern Rockies 12z Tue and into.
This wave will continue northeast and merge into a broader but also weak trough over the Great Lakes during the period.