Aikyam-Lab/Synoptic-Bench huggingface dataset:
High temperatures will be cooler across northeast and central MO and west central IL behind the cold front due to low level cold air advection along with low level cloudiness inhibiting diurnal solar insolation. Only a slight chance of showers is expected on Wednesday across northeast and central MO and west central IL as the front weakens and an upper level ridge builds over the OH and TN Valley regions. Most of the precipitation will be in the Plains ahead of a slow moving, cut-off upper level low over the Four Corners region.
08z surface analysis had low over northwest CO with inverted trough into eastern WY. Water vapour had upper low spinning into northern UT with departing jet streak across the northern plains. Frost/freezing temperatures continue to look probable, but will hold off on headlines for two reasons. One, winter headlines for snow imply freezing temperatures.
Lows will definitely fall into the low to mid 30s, though, with MOS guidance and NAM/RAP consistently lower than other guidance showing temperatures below freezing for some locations.
A shallow cold front will slide into NE OK and will bring a wind shift to the north at KBVO around 00Z and at TUL and RVS around 03Z. At the same time, an unseasonably strong polar front continues to surge south across the high plains with strong isallobaric forcing centered over eastern CO. Areas along and west of US 75 appear to have the best shot at seeing much cooler temps during this time frame, with points east most likely staying on the warm side.
Near or below freezing temperatures continue early this morning across much of western and central North Dakota. Late tonight into Wednesday morning near or sub- freezing temperatures are likely once again, this time with less cloud cover expected.
620 AM EDT Tue Sep 8 2020 High pressure will shift farther off the Northeast coast by midweek with a stronger onshore flow pushing front and plenty of moisture back on shore.
Another warm and dry day is expected with afternoon high temperatures in the low to mid 90s. High pressure centered over the Appalachians will begin to retreat northeastward over the next 24 hours.
/issued 248 AM CDT Tue Sep 8 2020/ Above normal temperatures will continue across the Mid-South for the remainder of the work week as an upper ridge of high pressure is expected to build over the Mid-South. Although, some of the CAM models are showing a few showers developing late tonight into Wednesday morning across Eastern Arkansas which will still be on the periphery of the building ridge.
The ejecting upper low will bring a good chance for showers and storms to the area this weekend; otherwise, tranquil weather will prevail as forecast temperatures start to reflect more autumnal readings with highs mostly in the 70s. Cold front which has entered the NW half of the area will slowly lift back to the north with time which will help KFWA remain mostly VFR and free of precip.
516 AM MDT Tue Sep 8 2020 Upper low will cut off from the main flow today and meander over Utah and western Colorado through the short term period. Accompanying surface cold front will usher in much colder temperatures, windy conditions and a mixed bag of wintry precipitation to western parts of the area tonight and Wednesday morning. Tonight, as temperatures begin to fall into the lower 30s expecting a wintry mix in northeast Colorado and adjacent counties of northwest Kansas and southwest Nebraska.
As of 08Z Tuesday morning, the well-advertised cold front was slowly progressing across the forecast area and currently stretched across southern portions of Coffey and Anderson counties. Temperatures by afternoon will fall into the upper 40s across north-central KS to the lower 60s across far east-central KS.
645 AM EDT Tue Sep 8 2020 High pressure east of the area allows very warm weather this week.
All eyes are watching as a strong Canadian cold front, currently located across southern Kansas and southeast Colorado, makes its way southward.
Another mild night is in the forecast, as high pressure at the surface and aloft controls the weather. Low temperatures overnight should be a touch warmer, into the mid/upper 60s with light winds. Deep troughing will translate into a cut-off low over the 4-Corners region tonight and on Wed. Another upper low near 35N145W, with upper ridging in place, appears to set up Omega style blocking over western CONUS. This will help maintain similar conditions going for the middle of the week; generally sunny skies and highs a bit warmer, rising into the mid 80s to lower 90s.
643 AM EDT Tue Sep 8 2020 High pressure will cover the Mid Atlantic region and Carolinas today and tonight. A very strong cold front will extend from the New England to the southwest United States today before low pressure develops along the front over the Southern Plains and tracks into the Ohio Valley over the weekend.
647 AM CDT Tue Sep 8 2020 A deep longwave trough over the Northern Plains will continue to dictate weather conditions over the next couple days.
651 AM EDT Tue Sep 8 2020 Going to feel like summer again this week with large ridge of high pressure planted over the Eastern U. Large ridge of high pressure will be set up over the region through the period. Ridging aloft builds in today with upper level heights rise, however, can't rule out an afternoon shower/thunderstorms around peak heating, especially within the vicinity of cold frontal forcing from the Finger Lakes to Mohawk Valley.
High pressure centered over the Appalachians will begin to retreat northeastward over the next 24 hours.
733 AM EDT Tue Sep 8 2020 A front will remain stalled just north of Pennsylvania over the next two days, as a strong upper level ridge expands westward into the Mid Atlantic region.
Gusty north to east winds continue to increase and spread southward early this morning as surface pressure gradients tighten behind a dry cold front dropping south through the Great Basin.
617 AM EDT Tue Sep 8 2020 A front will remain stalled just north of Pennsylvania over the next two days, as a strong upper level ridge expands westward into the Mid Atlantic region.
Mesoscale analysis currently shows a land breeze or frontolytic trough boundary situated off the coast extending from Apalachee Bay, arching to near Marsh Island where some convection as erupted in the past couple of hours. 8 values south of boundary, then 2+ inches farther south over the warmer waters. A general steady advancement of the more humid air should take place over the next several days, perhaps enhanced at times with easterly wave traffic across the lower and central gulf.
Other than some possible valley fog early this morning, a dry atmosphere will keep our skies mostly clear while high pressure over the Appalachians provides us with a light south breeze today. Lows will be just a few degrees warmer than normal in the 60s.
Ensembles point to a split upper flow regime over the next several days with a closed low over the southwest U. Late in the period the closed low will gradually lift toward the north, which may result in increasing chances for some showers, but thus far pops were kept light and fairly spotty across the CWA.
930 AM EDT Tue Sep 8 2020 A front will remain stalled just north of Pennsylvania over the next two days, as a strong upper level ridge expands westward into the Mid Atlantic region.
/Issued 420 AM EDT Tue Sep 8 2020/ 500mb analysis shows high pressure centered across west central TX with a ridge stretching into the Great Lakes. High pressure across the western CWA has retreated west a bit as compared to yesterday, while an inverted trough remains situated across the SE coast of the US. The high pressure ridging will remain west of the CWA through the period, and the inverted trough will move inland through Wednesday. More tropical-like dewpoints in the lower 70s will return for Wednesday.
A strong storm system dropping into southern Utah will bring strong winds, much cooler temperatures and scattered showers and thunderstorms this afternoon into Wednesday.
Surface analysis revealed a cold front roughly just north of Wichita, KS to Kansas City, MO to Springfield, IL. Again the highest chances for this are along and especially north of Interstate 44. Have trended closer to the high res guidance and NAM which typically handles shallow airmasses better. The cold front may stall along I-44 this evening before attempting to lift north a tad tonight as more of an inverted trough takes shape with the progression of the upper level cut off low to the west. The upper low moves very little on Wednesday and with the lack of upper level support we have nudged highs up into the middle 80s (cooler in the northwest) along with a decrease in PoPs.
A long wave trough stretches southeast to near west-central Cuba. A short wave trough riding along the southern flank of the larger trough axis is apparent on water vapor imagery just to the north of the Yucatan Channel. A broad and lengthy low- level trough reaches from the Yucatan to north of the northern Bahamas. Deep tropical moisture straddles the inverted trough, corroborated by the 2.
A low pressure system pushing through the region will bring relief from recent very hot temperatures but gusty winds will maintain the dangerous fire weather conditions. Strong high pressure has been producing extreme heat across our area during the last few days, with highs topping out at least 10 to 15 degrees above normal again yesterday. A low pressure trough dropping through the Great Basin region is weakening and displacing the high pressure ridge and will bring us a downward trend in temperatures during the next couple of days. As the low pressure system drops south through the Utah area this morning and cold high pressure builds in at the surface, gradients will turn offshore and increase.
otherwise mainly dry and warmer weather can be expected through at least Wednesday night.
/issued 315 AM CDT Tue Sep 8 2020/ SHORT TERM (Now through Wednesday): A strong 500mb low dives into the Desert SW through the day today, as the resulting trough stretches northeastward through the Great Lakes. Weak mid level low pressure from West Texas through northern Mexico is pulled northeast today into the southwesterly flow aloft, potentially enhancing convective development late this afternoon into this evening across Deep South Texas.
High pressure to our west over the Pacific Ocean is forecast to start inching it's influence east by Wednesday.
533 AM MDT Tue Sep 8 2020 08z surface analysis had low over northwest CO with inverted trough into eastern WY. Water vapour had upper low spinning into northern UT with departing jet streak across the northern plains. Frost/freezing temperatures continue to look probable, but will hold off on headlines for two reasons. One, winter headlines for snow imply freezing temperatures.
1013 AM EDT Tue Sep 8 2020 High pressure east of the area allows very warm weather this week.
409 AM CDT Tue Sep 8 2020 A deep longwave trough over the Northern Plains will continue to dictate weather conditions over the next couple days.
A strong storm system dropping into southern Utah will bring strong winds, much cooler temperatures and scattered showers and thunderstorms this afternoon into Wednesday. Other than that, the cold front is making steady progress southward and is on Flagstaff's doorstep with gusts 45-55 mph fairly common behind it. That front will sweep through our area this evening and until then we will be dealing with increasing pre-frontal southwest to west winds this afternoon where gusts to around 35 mph can be expected in the valleys and 40+ mph over the higher terrain. Much cooler temperatures will also move in and be most noticeable by Wednesday with highs well below normal.
Dry and slight cooler weather can be expected for Wednesday night through the end of the week. Locally heavy rainfall will be possible as well, given the high PW values and that the storms could train over the same area through the period. High pressure will dominate the area for the last part of the week with dry and relatively cooler conditions. This high pressure will push the front well south and keep anything from moving into the area from the northwest. Then for the weekend, a mid level trough will move toward and through the area.
While moisture still continues to be limited across the area, evident by mesoanalysis showing PWATs still below an inch, there has been a return of some moisture today, especially in the low levels with dew points climbing back into the 60s. The 12z sounding out of Charleston also shows increased onshore flow out of the east in the low and mid levels which will steadily allow for moisture to return through today. Lows Wednesday night fall into the lower 70s, with is above normal.
A large ridge of high pressure continues to amplify offshore in the Pacific Northwest.
It will become warmer during the period with the mercury forecast to climb well into the 80s for many areas on Wednesday.
A cut-off low that brought the wet and cool conditions to the area over the Labor day weekend has sunk into the southern Rockies.
Highs this afternoon will range from near 70 northwest to the low 80s southeast. The ejecting upper low will bring a good chance for showers and storms to the area this weekend; otherwise, tranquil weather will prevail as forecast temperatures start to reflect more autumnal readings with highs mostly in the 70s.
230 PM CDT Tue Sep 8 2020 A ridge both at the surface and aloft has provided dry and warm weather conditions to the region.
Low-mid level inverted trough off just our coast will continue the periods of showers and isolated thunderstorms tonight. Winds and shower activity will decrease by morning as the trough shifts inland.
217 PM EDT Tue Sep 8 2020 High pressure will cover the Mid Atlantic region and Carolinas tonight. A very strong cold front will extend from the New England to the southwest United States tonight before low pressure develops along the front over the Southern Plains and tracks into the Ohio Valley over the weekend.
The large scale pattern across the CONUS is characterized by a large trough across the western US and a ridge across the eastern US with a boundary across the region here locally.
Most locations will be in the upper 40s to mid 50s, with the warmer highs expected across east central SD where cloud cover may decrease enough for some peeks of sunshine. Cooler high temperatures are anticipated across northwestern IA, where showers are expected.
Otherwise, highs in the upper 40s to the lower 50s for this afternoon look fine. Lows will definitely fall into the low to mid 30s, though, with MOS guidance and NAM/RAP consistently lower than other guidance showing temperatures below freezing for some locations.
1247 PM EDT Tue Sep 8 2020 High pressure provides very warm weather this week.
314 PM EDT Tue Sep 8 2020 A front will remain stalled just north of Pennsylvania over the next two days, as a strong upper level ridge expands westward into the Mid Atlantic region.
/issued 1045 AM CDT Tue Sep 8 2020/ The 12Z BRO sounding indicated a distinct drying in the lower to middle levels since yesterday. With lower rain chances and more sunshine, highs should be at least several degrees warmer today than yesterday.
126 PM MDT Tue Sep 8 2020 Upper low will cut off from the main flow today and meander over Utah and western Colorado through the short term period. Accompanying surface cold front will usher in much colder temperatures, windy conditions and a mixed bag of wintry precipitation to western parts of the area tonight and Wednesday morning. Tonight, as temperatures begin to fall into the lower 30s expecting a wintry mix in northeast Colorado and adjacent counties of northwest Kansas and southwest Nebraska.
Mixed out dew points in the 20s/lower 30s this afternoon should settle in over the northern and western parts of the cwa in the upper 20s to the lower 30s after the mixing subsides this evening. Therefore, with the light winds and dew points, expect freezing to below freezing temperatures across north central sd.
A weak upper level disturbance is moving southeastward over southern MT and northern WY, with a few snow showers occurring ahead of it in the higher terrain south of Billings. Todays temperatures will be slightly warmer than yesterday but still well below normal before reaching record lows for the second night in a row tonight. High temperatures today will remain in the upper 40s to low 50s before warming into the low to upper 60s.
Periods of light rain are possible Wednesday night associated with weak forcing and continued moist, warm air advection operating on aloft on the front side of a stalled upper level low across the Four-Corners region of the wrn U. The temperature forecast leans on the warmer deterministic based short term model blend for lows in the 30s tonight and Wednesday night and highs in the 40s Wednesday. Sensible heating from the relatively warm ground should be the dominate force to hold overnight temperatures above freezing.
While moisture still continues to be limited across the area, evident by mesoanalysis showing PWATs still below an inch, there has been a return of some moisture today, especially in the low levels with dew points climbing back into the 60s in the eastern half of the forecast area. The 12z sounding out of Charleston also shows increased onshore flow out of the east in the low and mid levels which will steadily allow for moisture to return through today.
Tonight we will see a bit more moisture return given the placement of the high and this will lead to an increase in mainly river valley fog. Another night of ridge/valley temperature splits are on order. The question remains just how warm we will get on Wednesday, as we have been cooler today than forecast and we see a similar setup for tomorrow. Also, another factor for cooler highs today could be some upper level smoke present based off of the HRRR smoke product and a hazy look when looking in the sky this afternoon.
Taking a look at the bigger picture, a mid level low will continue to dig south into the Desert Southwest today, while ridging is persists over the eastern U.
Still thinking the greatest coverage for showers/storms today will be across southeast KS in vicinity of the cold front. Temperature contrast either side of the cold front today will pose a challenge, as we expect the cold front to stall/slow down with daytime heating over southern Kansas. Meanwhile anticipated environment ahead of the cold front in southeast Kansas, MLCAPE in the 2000-3000J/kg range with surface front parallel to wind shear vectors favors linear/multi-cell storm mode.
Warmer temp aloft appear to be the main contributor, lacking any other notable change in other convective parameters since the weekend.
255 PM MDT Tue Sep 8 2020 Early afternoon WV/IR imagery showed the upper low drifting to the south over eastern UT. Areas to the south and east received lighter snowfall mixed with freezing drizzle. These waves will provide additional lift for wintry precipitation in the form of snow and freezing drizzle, along with patchy fog.
While moisture still continues to be limited across the area, evident by mesoanalysis showing PWATs still below an inch, there has been a return of some moisture today, especially in the low levels with dew points climbing back into the 60s in the eastern half of the forecast area. The 12z sounding out of Charleston also shows increased onshore flow out of the east in the low and mid levels which will steadily allow for moisture to return through today. Lows Wednesday night fall into the lower 70s, with is above normal.
331 PM CDT Tue Sep 8 2020 Another cool night followed by a slightly warmer yet still cool day can be expected through the short term period. Wednesday then sees a shift to southwest flow which should bring slightly warmer temperatures to the region, although still well below normal.
Lows tonight will be seasonal with temperatures dropping into the low 70s across the region. High temperatures are expected to climb into the low 90s for much of the region.
Fortunately, cooler northern air masses dominate synoptic scale flow keeping the oppressive heat away.
210 PM EDT Tue Sep 8 2020 A front will remain stalled just north of Pennsylvania over the next two days, as a strong upper level ridge expands westward into the Mid Atlantic region.
Dry and warm conditions can be expected tonight as upper ridging builds over the region in response to an upper low digging over the western CONUS. Ridging will be the dominant feature through the work week, maintaining dry conditions and warm temperature with readings approximately 10 degrees above average.
Currently, the previously forecast upper low over the Four Corners region has not advanced as far east as previous thinking would have indicated. Right now, still ended up with 43 as the low which is another tie for the record should that be the case. However, should drier dewpoints push in to the area, then perhaps the low could be lower. Meanwhile, for the day on Wednesday, a similar gradient of around 50 degree temperatures should remain in place from the northwestern areas to around the low 60s over far east central KS. Lows cold again for Wednesday night but slightly warmer than tonight.
(This evening through Wednesday) Showers and thunderstorms will continue to develop along and just ahead of the cold front through this afternoon and evening. Based on current trends with the progression of the cold front, would expect the NAM12 solution to be close by Wed 12Z.
The low will continue to weaken, and high pressure settles back over the peninsula, centered off to our east.
A closed low now over Utah will slowly slide south into the Four Corners region over the next few days before ejecting northeast into the northern Plains early this weekend. A warming trend with continued rain and thunderstorm chances continues into the weekend as the above mentioned upper low moves into the northern Plains.
233 PM MDT Tue Sep 8 2020 Upper analysis shows a NE-SW oriented upper trough across the forecast area extending to a deep low pressure system over the four corners area in the southwestern CONUS. An area of enhanced mid-level frontogenesis continues to slide slowly southeastward across southwestern and south central South Dakota, producing a narrow band of rain, with some areas of snow along the higher terrain of the Pine Ridge in southwestern South Dakota. At the surface, dry and very cold high pressure continues to flow into the region. Dewpoints in the lower 20s over northeastern Wyoming and northwestern south Dakota point to the possibility of low temperatures well below freezing tonight so have issued a Freeze Warning for northeastern Wyoming and much of western South Dakota.
The upper level jet will remain well to the northwest of the area today and tonight as a closed low drops into the four-corners this evening.
245 PM CDT Tue Sep 8 2020 WV imagery shows the upper trough now over eastern UT. Models dig this to the UT/AZ border by 00Z Thu, before ejecting the trough to the upper MS Valley by 18Z Sat. At the sfc, the cold front is just NW of KLUB as per area radars, and appears to be slowing as diurnal heating takes place. Speaking of, the latest HRRR develops convection along a weak dryline up against the higher terrain 19-20Z, w/development along the front 20-21Z, putting everything east of the Pecos, as well as the Stockton Plateau/lwr Trans Pecos, in a warm sector w/dewpoints mostly in the 60s.
Temperatures this morning were chilly, dropping into the 40s in the lower valleys with 30s in the mountains and high valleys. The low pressure system which brought yesterday's cold front and high winds will remain centered over Utah today, keeping our area under a cool northeast flow aloft. Overnight low temperatures tonight, under clear skies and light winds, could be a few degrees cooler than last night, dropping into the upper 30s to mid 40s in the lower valleys.