Aikyam-Lab/Synoptic-Bench huggingface dataset:
Over the northern Rockies and Great Lakes region two closed off upper lows sit.
High pressure to the north will build into the area which will shift winds to the northeast by early afternoon. This will keep the beaches a little cooler with high temperatures in the upper 70s. High pressure over the northeastern Gulf and Panhandle of Florida will build over the area this morning. A northeasterly wind surge will push southwestward over the Atlantic waters behind an area of low pressure east of the Mid Atlantic states this morning. A sea breeze/weak frontal boundary from the area of low pressure will then push into the coastal areas this afternoon. Weak high pressure will push east of the area tonight, and settle over the western Atlantic to the Carolinas. Overnight lows will be in the mid 50s to the lower 60s.
The westerly flow aloft that has been in place across the central High Plains region turns more southwesterly today and brings a short wave trough out of the southwest U. That initial short wave trough will help induce precipitation across the region that begins as a light rain and snow mix this evening and changes over to mostly all snow by early Wednesday morning before changing back to a light rain and snow mix as it tapers off Wednesday morning.
Then, the upper low and its short waves will make its way into the area this evening and tonight. The track and position of the upper low will be such to favor the highest chances North, and lowest chances South tonight. The center of the low is then expected to move right across the heart of the area on Wednesday. This will bring a few more instability showers, that will be boosted by short wave energy rotating around the low.
310 AM MDT Tue Apr 13 2021 Current surface analysis shows low pressure over northern MN, with high pressure over southwest Canada. An upper level low settles south across the western US by Wednesday and then slowly moves east-southeast across the Rockies into the Central Plains late week and gradually weakens with time.
Despite the cold frontal passage yesterday, winds across the area have already acquired an onshore component.
/GG/ Wednesday night through Next Tuesday: Rain and storm chances will continue into Wednesday evening/night as a cold front pushes through the ArkLaMiss.
409 AM CDT Tue Apr 13 2021 Weather conditions across this forecast area today will continue to be influenced by a nearly vertically stacked low pressure system through the low to mid-levels located off to our northeast. Occasional light snow showers have been observed through the early morning from Mobridge to Aberdeen to Ortonville and points north. Some light accumulation will be possible across the higher terrain of northeast SD.
Below normal temperatures should continue for the remainder of the work week with persistent surface ridging from the Northern Plains southeast into MO and IL.
Otherwise, expect scattered clouds to increase across the area today downstream from broad troughing over the western US. The NAM along with many of the hi-res models are highlighting areas roughly along and east of the I-44 corridor for the highest QPF totals.
457 AM MDT Tue Apr 13 2021 Current surface analysis shows low pressure over northern MN, with high pressure over southwest Canada. An upper level low settles south across the western US by Wednesday and then slowly moves east-southeast across the Rockies into the Central Plains late week and gradually weakens with time.
715 AM EDT Tue Apr 13 2021 An upper low will drop down over PA from the Upper Great Lakes over the next few days.
319 AM MDT Tue Apr 13 2021 Broad area of cool air aloft associated upper lows over MN/WI and the Great Basin is contributing to instability over south central MT this morning. This instability combined with a moist layer in the lower to middle levels and air moving around and then downwind of the Snowy Mountains [low level convergence] is facilitating snow shower activity around and just west of Billings. We then expect an overall drying trend during the day as subsidence moves over our area, in between an upper low over MN/WI and another upper low over the Great Basin.
Upper level flow is generally zonal this morning as a closed low continues to churn over the upper midwest. A blocking high over eastern Canada has kept this broad trough nearly stationary for a few days.
The pattern of upper lows to the north and persistent northwest to north low-level flow is still progged to remain in place into Wednesday night. Forecast temps over the next few periods are close to persistence though have temps Wednesday a bit lower behind a weak cold front. Near-freezing temps are still expected but am not confident enough in a widespread frost for an Advisory.
424 AM MDT Tue Apr 13 2021 Satellite imagery shows some lower clouds beginning to make their way into SE Wyoming as a low pressure system from the Pacific northwest makes its way southward and eastward today and tomorrow.
Melting during the day is once again expected as temperatures climb into the upper 20s to low 30s and roads rise above freezing.
420 AM PDT Tue Apr 13 2021 A low pressure system will move into the Great Basin, strengthening the onshore for southern California and deepening the marine layer through Wednesday with periods of stronger and gusty west winds in the mountains and deserts.
Dry westerly flow continues today as the gradient tightens slightly as an upper low drops into the Great Basin.
626 AM EDT Tue Apr 13 2021 Cooler weather will start to settle into the region over the next 24 hours and linger till later this week. Pattern shift underway as the next in a series of closed upper lows moves through the northern stream and slowly across the northern Great lakes. Trough should pass through dry with little moisture to work with. Winds will pick up with the trough with some RH values dropping to either side of 30% across the area.
Breezy onshore winds are forecast for Tuesday along with cooler temperatures across the interior. Meanwhile, a mid/upper level low and associated trough over the Pacific Northwest will advect cooler air over the region today.
This will lead to warmer temperatures than elsewhere along the coast. Looking into the extended timeframe, a ridge builds along the PNW.
Warmer temperatures and dry weather late week into the weekend. The forecasted upper level trough is beginning to move south into northern California & Nevada early this morning. Ensemble guidance remains in good agreement that this trough will form a cutoff low as it moves south along the CA/NV border today. Winds are forecast to increase this morning as the trough first moves over the area and surface pressure gradients tighten. Precipitation chances continue to increase over the mountains and upper foothills today through Wednesday as ensemble guidance shows the upper trough lingering over Nevada with multiple impulses moving along it through the forecast area.
Today will be much cooler in the wake of yesterday's cold front due to continued northeast low level flow and abundant cloud cover.
An upper level low was situated northwest of Duluth MN early this morning.
727 AM EDT Tue Apr 13 2021 An upper low will drop down over PA from the Upper Great Lakes over the next few days.
946 AM CDT Tue Apr 13 2021 Deformation zone precipitation continues to wrap into the region as the upper low gradually pulls east over Lake Superior today. Made some minor adjustments to POPs as the upper low continues to spin over our area and snow continues. Cut off upper low continues to rotate over the DLH area, and is not expected to move much today. Could see an additional 2 to 3 inches, mainly near the Canadian border, although of course totals will be impacted by melting and warmer temperatures this afternoon. Looking at the larger scale pattern, nearly zonal flow prevails across the southern CONUS, with ridging over the Pacific Northwest, and a developing trough to the east.
Computer models have been very consistent with the area of low pressure moving away from the region late tonight, with a high pressure building behind it. A drier and warmer weather pattern is forecast to be established by the end of the week.
For 12Z Aviation discussion below The sheared out upper low will remain sprawled out from the Central Plains across the Great Lakes during the short term period, moving only slightly eastward through Wednesday. These bursts of heavier frozen precip would have the highest potential to accumulate on grassy surfaces, but would still amount to 1" or less. Wednesday will be notably drier and 5-10 degrees warmer as the low shifts farther east, but there could still be isolated rain showers popping up with cyclonic flow in place. Two slow-moving upper level lows over the CONUS will continue to influence the upper Midwest's weather throughout the forecast period. The upper low that is currently over northern Minnesota will move into the Great Lakes, allowing a reprieve from the rain and snow showers.
Over the northern Rockies and Great Lakes region two closed off upper lows sit. On Wednesday morning, under the right entrance region of an upper level jet, a northeast to southwest oriented cold front is expected to strengthen near the KY and TN border.
This cooler and more stable air mass was then likely displaced as surface temperatures quickly warming just after sunrise. To the west of this feature, a disorganized area of low pressure sits along a frontal boundary near the ArkLaTex region, which is triggering some convection over Louisiana. , pinched between a broad upper level trough over the western North Atlantic and a potent trough over MN. Moisture will remain incredibly limited to the lowest levels with large scale subsidence aloft severely depressing any chances of rain through the short term.
541 AM MDT Tue Apr 13 2021 Satellite imagery shows some lower clouds beginning to make their way into SE Wyoming as a low pressure system from the Pacific northwest makes its way southward and eastward today and tomorrow.
Highs in the lower to middle 60s are generally expected, though southern sections, where thickening clouds and earlier rain chances may keep temperatures from breaching 60 degrees. Clouds will thicken/lower from southeast-to-northwest tonight, causing temperatures to flatline in the lower and middle 40s. However, as the low-level moisture surges northwestward, areas of drizzle, sprinkles or a few light showers will be possible across most/all of the area early Wednesday morning. Wednesday an upper level closed low will remain anchored over the Great Basin region with southwesterly flow over the CWA. As intermittent disturbances round the base of the low the upper level flow will transport them over the FA.
924 AM EDT Tue Apr 13 2021 Dry weather is expected today under weak high pressure.
651 AM CDT Tue Apr 13 2021 Made some minor adjustments to POPs as the upper low continues to spin over our area and snow continues. Cut off upper low continues to rotate over the DLH area, and is not expected to move much today. Could see an additional 2 to 3 inches, mainly near the Canadian border, although of course totals will be impacted by melting and warmer temperatures this afternoon. Looking at the larger scale pattern, nearly zonal flow prevails across the southern CONUS, with ridging over the Pacific Northwest, and a developing trough to the east.
Weather conditions across this forecast area today will continue to be influenced by a nearly vertically stacked low pressure system through the low to mid-levels located off to our northeast. Occasional light snow showers have been observed through the early morning from Mobridge to Aberdeen to Ortonville and points north. Some light accumulation will be possible across the higher terrain of northeast SD.
934 AM EDT Tue Apr 13 2021 A very dry airmass remains in place with high pressure across the region. Despite a light low level N/NE flow, temperatures will be very warm today under sunny skies, with highs reaching the low 80s along the coast and mid to upper 80s across the interior.
/12Z TAFS/ There looks to be an abundance of MVFR cigs in the forecast for all terminals given the shallow cold front and moisture pooling over South Central TX. At DRT the front will be more shallow and persistent; models show a couple periods where scattered showers could form, for this reason, will go with the lower cigs closer to the MAV MOS through the period there. Locally higher chances might be found near and west of DRT and over by and south of the La Grange area where there appears to be better surface convergence along the cold front. For lows Wednesday morning, the air might feel a few degrees cooler, but lows are expected to be roughly the same, the the cooler feel will be due to a drop in dewpoints.
Weak mid-level short wave energy will move across the region this morning with an weak inverted surface trof in place to the south of the forecast area over srn TN. However, another very light QPF event event will be possible later tonight into Wednesday morning, mainly over southern portions of the forecast area as yet another very weak H50 short wave zips eastward through the lower/mid MS River Valley.
1029 AM EDT Tue Apr 13 2021 Quiet weather is expected to continue through Wednesday as we remain trapped between two upper level lows.
607 AM CDT Tue Apr 13 2021 130 AM CDT A mainly quiet short term forecast although a transition to cooler weather will unfold. The expansive closed low centered over the Upper Midwest is impossible to miss on this morning's satellite imagery. With the cooler air oozing in, temperatures look to drop into the lower to mid 30s in outlying areas, with coolest readings near freezing in north central Illinois. Wednesday looks to be the coolest day this week as the aforementioned upper low moves into the central Great Lakes and sloshes colder air further southward. Northwest winds will be blowing around 15 mph, providing an afternoon wind chill in the low 40s in the north.
Cooler temperatures expected today through before a warming trends returns for the weekend. The upper level low has dropped south into eastern Oregon this morning. This has started to increase north to northeast winds to around 20 to 30 mph over the exposed ridges this morning. RH is currently around 40 to 50 percent on the ridges. High temperatures across the interior will be 5 to 10 degrees cooler today than yesterday in most areas and may struggle to reach 70 in many locations. The challenge will be which areas will decouple and allow temperatures to drop into the low to mid 30s.
Associated cold front drops into north Georgia during the day tomorrow and slowly sinks south and east into central Georgia Wednesday night.
High pressure will shift off the se coast on Wednesday and winds will become southerly. High pressure over the northeastern Gulf and Panhandle of Florida will build over the area this morning. A northeasterly wind surge will push southwestward over the Atlantic waters behind an area of low pressure east of the Mid Atlantic states this morning. A sea breeze/weak frontal boundary from the area of low pressure will then push into the coastal areas this afternoon. Weak high pressure will push east of the area tonight, and settle over the western Atlantic to the Carolinas. Overnight lows will be in the mid 50s to the lower 60s.
As for rain chances, an upper level low will remain centered across the Intermountain West, placing the forecast area in west southwest flow aloft. Most areas will top out in the upper 50s to mid 60s, although a few locations in our southeast counties may reach the lower 70s.
123 PM EDT Tue Apr 13 2021 Quiet weather is expected to continue through Wednesday as we remain trapped between two upper level lows.
The highest rainfall totals, albeit meager, look to be across the southern half of the area.
A weak surface front was located over southern Arkansas with cooler north winds over the region holding temperatures down in the upper 60s to lower 60s.
SR Chattanooga Airport, TN 81 54 73 49 66 / 10 10 70 10 10 Knoxville McGhee Tyson Airport, TN 75 53 71 47 63 / 20 10 70 30 10 Oak Ridge, TN 74 53 70 45 63 / 20 10 70 30 0 Tri Cities Airport, TN 68 50 70 45 59 / 20 10 60 40 0.
224 PM MDT Tue Apr 13 2021 Broad upper level troughing will dominate most of the period, supporting below normal temps with unsettled and breezy conds at times. Double barrel upper low over the northern CONUS is supporting cool, breezy and mostly cloudy conds over much of the region today. Eastern closed low will pull away Wed, with the western CONUS trough slowly beginning to progress east. This will allow for much less wind Wed, with slightly warmer temps. Western CONUS trough will shift east Wed as a northern stream upper trough phases across the northern plains, allowing for an overall slow progression of low heights over the region.
215 PM CDT Tue Apr 13 2021 Cold front has pushed south into the ARKLATX region this afternoon.
Nevertheless, we're looking at another incoming bout of clouds/associated showers as another wave of energy rounds the base of the mean long wave Low, interacting with the moisture in the wswlies streaming across the Lower Mississippi River Valley; not dissimilar to last night-this morning. After its passage, northwesterlies funnel in cooler air Wednesday later Wednesday and Wednesday night, perhaps cool enough for frost in our north, where some 30s appear.
BREEZY EAST/NORTHEAST WINDS ACROSS NORTHERN ROCKIES THROUGH A closed low pressure circulation over the Great Basin will continue to bring gusty east and northeast winds across much of the Northern Rockies through Wednesday. For low elevations, wind gusts will be in the 25-35 mph range, while ridgetops and high terrain will experience occasional gusts over 50 mph at times.
One more wave rotating around the upper low will move through the northeast CWA tonight, with more light snow expected.
Near the surface, high pressure remains situated from the high plains of eastern Wyoming into eastern Colorado and extreme western Kansas. There is an outside chance for light precip developing across portions of extreme western Kansas late tonight as a closed off upper low drops southward into the Great Basin. Short range models indicate the first in a series of H5 vort maxima and an associated small +90kt upper level jet core ejecting out of the Southern Rockies into the high plains of western Kansas generally after midnight. Despite drier air prevailing in the lower levels, a few areas of light rain will be possible late overnight through daybreak, mainly in portions of west central and southwest Kansas.
109 PM EDT Tue Apr 13 2021 A ridge will build over the Ohio Valley today with low pressure positioned across the Upper Great Lakes.
246 PM CDT Tue Apr 13 2021 Another great day was unfolding across all of eastern Iowa, northwest Illinois and far northeast Missouri, with the area under influence from high pressure ridging extending from the central Great Plains into the Ohio River Valley. High pressure will remain in control of our weather for through Wednesday, meaning quiet weather with mainly dry condtions are expected. Temperatures are expected to fall into the low to mid 30s here.
High pressure will then expand south and east into the mid- Mississippi River Valley with a building extension into the Upper Midwest. However, the mid-and-upper level presence of the slow-to-depart and expanding upper low moving into the northeast CONUS will maintain sufficient moisture aloft to keep clouds in place through the period. Temperatures will increase slightly today through tomorrow, owing to the departure of the low pressure systems and lack of precipitation. After highs today only in the low 30s to low 40s, max temps on Wednesday will climb to the 40-50 degree range.
High pressure conditions continue to dominate the weather pattern today resulting in another bout of clear skies and mostly mild winds.
123 PM EDT Tue Apr 13 2021 Cooler weather will start to settle into the region over the next 24 hours and linger till later this week. Pattern shift underway as the next in a series of closed upper lows moves through the northern stream and slowly across the northern Great lakes. Trough should pass through dry with little moisture to work with. Winds will pick up with the trough with some RH values dropping to either side of 30% across the area.
313 PM EDT Tue Apr 13 2021 A ridge over the area will persist into Wednesday as a broad low pressure over the north-central United States begins to move over the Great Lakes region.
154 PM PDT Tue Apr 13 2021 A low pressure system will move into the Great Basin, strengthening the onshore flow across southern California as well as deepening the marine layer through Wednesday with periods of stronger and gusty west winds in the mountains and deserts. WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO -Forecast Highlights- * Patchy drizzle coast to mountain slopes through Wednesday * Cool through Wednesday, turning much warm by the weekend An upper low will meander over Nevada through Wednesday evening before departing to the east.
331 PM CDT Tue Apr 13 2021 As of 20z, the closed upper low continues to spin over the Upper Midwest with a trough diving south across the western CONUS. Temperatures fall to near freezing near the KS/NE border with mid and upper 30s expected further south. A more northerly component to the wind behind the front will lead to slightly cooler temperatures on Wednesday; highs will be in the mid to upper 50s.
1203 PM EDT Tue Apr 13 2021 A cold front will bring scattered showers and thunderstorms Wednesday with much cooler and drier air behind it to wrap up the work week. Despite the cooler temps, the continued dry nature of the air mass will result in very low RH across much of the area this afternoon.
244 PM MDT Tue Apr 13 2021 Satellite imagery shows an upper low over MN, and another to our west over OR, leaving us within the quiet col region. Wednesday should be a mostly dry day as mid levels become warmer and shallow instability becomes even more shallow. Snow chances will increase Wednesday night as upper low moves to northern UT and a vort max lifts thru WY.
As more convection develops, the effects of the cooler air from the storms combined with a weak disturbance aloft moving across the Southern Plains should help to move the front farther south and eventually south of the forecast area by noon Wednesday. However, a fast zonal flow aloft will develop over the region on the southern periphery of a blocking pattern, which will continue to bring a series of weak disturbances over the Southern CONUS.
SHORT TERM (Now through Wednesday Night): Nearly-zonal mid level flow will continue over the area while a cold front drifts very slowly southward across southern Texas.
Tonight skies will sct out to only mid/high clouds (possibly favoring some radiation fog at TRI) before lower clouds build back into the area late the period as moisture streams in aloft ahead of an approaching cold front. CDG Chattanooga Airport, TN 56 74 49 66 43 / 10 60 10 10 0 Knoxville McGhee Tyson Airport, TN 53 72 47 63 40 / 10 70 30 10 0 Oak Ridge, TN 52 70 45 63 40 / 10 70 30 0 0 Tri Cities Airport, TN 50 71 45 59 37 / 10 60 40 0 0.
906 AM PDT Tue Apr 13 2021 A low pressure system will move into the Great Basin, strengthening the onshore flow across southern California as well as deepening the marine layer through Wednesday with periods of stronger and gusty west winds in the mountains and deserts.
Pattern synopsis/forecast: Closed upper-level low pressure remains nearly stationary over Duluth this afternoon before ever so slowly meandering toward the far western UP overnight to near MNM/ESC by 12z Wednesday. Given early and midday sunshine, especially east of US-131, temps have boosted into the 50s across much of northern lower (just a tad cooler across the UP and near Lake MI). Heading into tonight, steady SSW to W winds will gradually draw in progressively cooler and increasingly moist air. Low temperatures tonight expected to range from the low to mid 30s- area-wide.
1225 PM MDT Tue Apr 13 2021 Satellite imagery shows some lower clouds beginning to make their way into SE Wyoming as a low pressure system from the Pacific northwest makes its way southward and eastward today and tomorrow.