Aikyam-Lab/Synoptic-Bench huggingface dataset:
Increasing moisture and convergence along a northward- moving inverted trough has resulted in a pretty impressive increase in convection over the past couple of hours across the Treasure Coast and adjacent Atlantic waters. As the trough continues to lift northward, coverage of showers and a few storms should continue to expand over the rest of the local Atlantic waters. Enough low-level steering flow will be able to continue bringing showers and a few storms onshore into at least the early overnight hours, but steering flow will then gradually become more out of the SW/SSW as the night goes on keeping the highest rain chances offshore.
636 PM EDT Sat Oct 24 2020 A cold front will stall south of the Commonwealth tonight. On Sunday, an area of low pressure track northward along the front, bringing light rain to parts of the state.
Winds will gradually ease and temps in many areas will drop below freezing overnight.
This will mean a bit warmer tonight so upped lows a tad.
Over the next 5 days, two upper level systems and an arctic high pressure system will be the major players in our forecast. The major trough will amplify over the Rockies in positively tilted fashion and this will allow for a strong surge of arctic air in in the lee of the Rockies.
720 PM EDT Sat Oct 24 2020 Dry and cooler conditions will continues across the area through Sunday.
A weak upper level trough will move away from The Midlands and CSRA on Sunday with a decreasing chance of showers and thunderstorms as the day progresses. It will be cooler than recent days with highs in the mid to upper 70s. High pressure aloft rebuilds across the Southeast U.
Lows tonight will generally be in the lower 50s. /issued 332 PM CDT Sat Oct 24 2020/ What a difference 24 hours makes? Temperatures are running nearly 35 degrees cooler across the area, in the wake of a cold front. The latest AMDAR soundings show a pronounced elevated inversion across the region, which will keep this low level moisture locked in through at least tomorrow.
Temps under the heavy cloud cover and steady NE surface winds have so far peaked around 50, but many places experiencing more clearing are in the low to mid 50s. As we move into the new work week, the upper level pattern will become increasingly amplified as an upper trough continues to dig southeast across the western CONUS.
/issued 256 PM EDT Sat Oct 24 2020/ High pressure in place to the NE and an area of low pressure over the western Caribbean is keeping easterly flow in place across the area.
The warm front-like boundary that was initially expected to hang up and focus heavy precip near the Keys has now moved north of the Keys instead.
TD 28 is expected to move northwestward around the periphery of a strong high pressure over the next couple days. As it moves into the central and northern Gulf of Mexico, an approaching upper level trough and cold front should cause it to turn more northward and then quickly northeastward by midweek. The exact track of the storm will depend greatly on when the trough arrives and when that north and northeastward turn happen.
the currently cooler temps under the mostly clear skies could continue to cool briefly as dewpoints were slowly rising back into the mid/upper 30s across these locations. As the clouds build back in temps could warm slightly back into the low 40s.
713 PM EDT Sat Oct 24 2020 High pressure ridge in place through the central Great Lakes and a static positioning to the upper level jet axis aloft leads to very little thermal advection locally through tonight. While these will wane with the loss in daytime heating this evening, low level flow will veer to the east during the night as expansive high pressure extends across the northern lakes. In light of how cold the low level airmass is and with sfc dewpoints down into the low 30s, nighttime cooling will still support mins well down into the 30s despite some uncertainty in cloud trends.
The low clouds cleared out of KMLC, the clearing line is likely to get close to KTUL and KRVS this evening. Clouds should fill back at these sites later tonight, with the low clouds holding over the Arkansas TAF sites.
902 PM EDT Sat Oct 24 2020 A cold front will sweep well offshore by evening on a gusty westerly wind. High pressure follows the front for tonight and Sunday with cooler temperatures and fair weather.
/issued 332 PM CDT Sat Oct 24 2020/ What a difference 24 hours makes? Temperatures are running nearly 35 degrees cooler across the area, in the wake of a cold front. The latest AMDAR soundings show a pronounced elevated inversion across the region, which will keep this low level moisture locked in through at least tomorrow.
757 PM EDT Sat Oct 24 2020 A weak low pressure system will bring a chance of showers to the area Sunday.
Weak upper trough continues moving eastward, with southwest/westerly flow in its wake overhead. This will keep the low level moisture in place and keep the cloud cover/drizzle over the region.
152 AM EDT Sun Oct 25 2020 An area of low pressure track northward along a front just to our south, bringing light rain to parts of the state. The low will slowly lift across western Pennsylvania by early Monday, keeping unsettled conditions in place through early in the week.
Over the next 5 days, two upper level systems and an arctic high pressure system will be the major players in our forecast. The major trough will amplify over the Rockies in positively tilted fashion and this will allow for a strong surge of arctic air in in the lee of the Rockies. Sunday and Monday, the minor trough will becomes embedded in the major trough and eject rapidly to the east and northeast across the central plains.
Total snowfall amounts from late Sunday night into Monday will average 1-2 inches for much of the area, with the higher amounts favoring grassy and elevated surfaces.
Meanwhile, subfreezing air is expected to seep into northwestern Oklahoma tonight, changing rain into freezing rain initially, and some sleet is likely toward morning on Monday, mainly in the far northwest. We are issuing a Winter Weather Advisory for the counties where impacts are most likely to occur, mainly for freezing rain. In addition, where subfreezing temperatures are very likely to occur, we are upgrading the Freeze Watch to a Freeze Warning.
By Monday, an upper ridge will begin to build over the Gulf of Mexico and a trough will amplify over the western CONUS. Meanwhile at the surface, a cold front is exiting our local area and moving to the east.
151 AM EDT Sun Oct 25 2020 Aviation -Cool week ahead; benign pattern -Chance of light precipitation late Sunday into Monday night -Late week southern stream storm needs watched -- Cool week ahead; benign pattern -- Surface ridging generally prevails for the next several days which keeps the low levels cool and dry.
An additional 2 to 3 inches could accumulate with this band, with the higher amounts closer to the southern border of our CWA. Bitterly cold air drifts in behind the system on Monday as surface ridging and an upper level trough slide into the Northern Plains. With that, highs on Monday will be in the lower to mid 20s.
116 AM EDT Sun Oct 25 2020 Dry and cooler conditions will continues across the area through Sunday. Post- frontal high pressure should maintain or slightly weaken through this evening and overnight hours. At the same time, an upper trough is forecast to slowly spill southwards along the Rockies and northern Plains. On Sunday, as the trough continues to slide further south along the Rockies, the upper flow across the area will become more southwesterly. Weak WAA will help to bring the 850mb front associated with yesterday's cold front back north while a surface reflection remains well south.
1140 PM MDT Sat Oct 24 2020 (25/00Z TAF Period) North to northeast flow aloft will prevail over Montana tonight through Sunday evening as the upper level trough continues moving southward. As this trough axis moves away, subsidence will bring an end to most areas of snow, while lingering longest in the Southwest mountains.
207 AM EDT Sun Oct 25 2020 An area of low pressure track northward along a front just to our south, bringing light rain to parts of the state. The low will slowly lift across western Pennsylvania by early Monday, keeping unsettled conditions in place through early in the week.
This could have an impact on the low temperatures if skies don't become mostly clear before sunrise but for now have kept current low temperature forecast intact.
and Monday High pressure was situated across the forecast area early this morning. Highs temps will range from the lower 30s across the Northwoods to around 40 along the lakeshore. Lows tonight should range from the upper teens northwest to the lower 30s near the lakeshore.
Additional accumulations of 1 to 4" of snow is expected, with the highest amounts across southeast South Dakota, northern Nebraska into northwest Iowa.
Diegan Chattanooga Airport, TN 74 64 75 61 76 / 10 10 10 10 20 Knoxville McGhee Tyson Airport, TN 74 61 74 59 73 / 10 10 20 10 20 Oak Ridge, TN 73 62 73 58 72 / 10 20 20 20 20 Tri Cities Airport, TN 72 55 74 56 71 / 30 10 10 10 20.
359 AM CDT Sun Oct 25 2020 Broad trough will be found across the state today. Trough and secondary surge of moisture exits the region tonight, with dry air behind this system.
After the cold start to the week, the EC and GFS continue to trend toward a more zonal configuration to the upper level flow for the later half - even ridging by the weekend (EC a bit quicker, stronger in this stead). There may even be some convective snow showers in the wake of cold front.
350 AM EDT Sun Oct 25 2020 Weak high pressure east of Florida will shift east today as Tropical Storm Zeta slowly lifts northwest through the western Caribbean Sea, and into the central Gulf of Mexico tonight and Monday.
The temperature forecast tonight through Sunday night also leans on the deterministic short term model blend which is cooler during the day and warmer by night than the guidance blend. If this occurs, the lows near zero in place across that area could easily be 5 or 10 degrees too warm. The record setting arctic high pressure system near Calgary this afternoon will drift through wrn and ncntl Nebraska Monday evening. The blended forecast suggested highs in just the lower 20s Monday. A period of strong radiational cooling Monday evening before the high moves south should set records.
Temperatures are generally in the lower to middle 20s under cloudy skies.
water vapor satellite imagery, heights, WSR-88D radar, and observations showed a broad mid-level trough across the northern third to half of the U. Through Sunday night, the longwave trough will rotate south and east so that by Monday morning it will extend from Northern Minnesota across South Dakota and Nebraska toward Colorado and New Mexico. Ahead of the trough we expect periods of lift and some frontogenesis, however the brunt of the storm system and stronger forcing is expected to remain to the southwest of the forecast area. The higher amounts would be over southeast Minnesota and northeast Iowa. North to northeast winds 5 to 15 mph, the drier air in the lower levels, stronger forcing to the southwest are responsible for the lighter amounts.
Into Sunday, a positively tilted upper trough amplifies over the Intermountain West. Our surface and low level winds will shift from the east/southeast to more of a northeasterly direction as low pressure in Colorado dives southward into Texas ahead of the upper wave. Rain is expected to transition to snow in northern and north-central KS late Sunday as temperatures near the surface and just above fall to below freezing.
1155 PM EDT Sat Oct 24 2020 High pressure ridge in place through the central Great Lakes and a static positioning to the upper level jet axis aloft leads to very little thermal advection locally through tonight. While these will wane with the loss in daytime heating this evening, low level flow will veer to the east during the night as expansive high pressure extends across the northern lakes. In light of how cold the low level airmass is and with sfc dewpoints down into the low 30s, nighttime cooling will still support mins well down into the 30s despite some uncertainty in cloud trends.
No IFR cigs are planned at this time, but would guess that the higher elevation at DRT would have the better chance considering the current dewpoint analysis. A weakening surface pressure gradient ahead of a cold front late tonight could lead to a more common IFR cig over the I-35 corridor by around 09Z Monday. This will result in warmer temperatures on Sunday, with highs forecast in the low to mid 80s for most areas. Showers may increase in coverage before sunrise Monday as low level convergence increases just ahead of the next cold front.
1014 PM CDT Sat Oct 24 2020 High pressure will continue to dominate the weather tonight with overnight lows expected in the 50s inland and the 60s along the beaches.
142 AM EDT Sun Oct 25 2020 A weak low pressure system will bring a chance of showers to the area Sunday.
Morning lows will settle into the low 60s. The forecast will depend heavily on the timing of a strong upper level low pressure system and the track of current T.
Moreover, a broad upper-level trough will become more positively-tilted as the day goes on, resulting in a northern pivot of an area of light snow over northwest Wisconsin. Most locations will see little to no snow accumulations resulting from the trough, as well as the lake effect snow. The only exception is the higher elevations of northern Iron county, where between 1 to 3 inches of snow will be possible, with some isolated amounts exceeding 3 inches. The main forcing from the upper-level trough will move out of the region this evening, resulting in a downward trend in snow over northwest Wisconsin.
Large jet feature will progress into the area within the southwest flow regime that becomes established along the periphery of this upper troughing.
Still carry slight chance PoP's across the higher terrain of the Smokys but even these chances really drop off toward the afternoon and early evening hours.
339 AM CDT Sun Oct 25 2020 Temperatures a little warmer than yesterday are expected, though cloud cover has been very slow to clear. At this time, expect limited clearing across parts of eastern Oklahoma before clouds fill back in as a cold front approaches later today/tonight. Models are trending towards warmer temperatures over the next several days though the GFS still remains the coldest.
This will bring mostly cloudy skies to western Kansas with pockets of drizzle or freezing drizzle as the day progresses. Light freezing rain will transition over to snow overnight as the temperatures drop below freezing. Lows tonight are anticipated to range from the low teens across west central Kansas to mid 20 s across south central Kansas.
Drizzle is also possible because of lingering moisture in the lower levels of the atmosphere. By Monday, an upper ridge will begin to build over the Gulf of Mexico and a trough will amplify over the western CONUS. Meanwhile at the surface, a cold front is exiting our local area and moving to the east.
353 AM EDT Sun Oct 25 2020 A few scattered light lake effect rain showers are possible south of Lake Ontario this morning, otherwise high pressure will bring dry and cool weather for the rest of the weekend.
This has contributed to a cooler day around much of the state w/ several locations below 50F over the Nrn half of the state. Aloft, mesoanalysis indicates that subtle longwave troughing is settling in across the CONUS. Aloft, stronger S/Wrly flow will setup over the Ern 2/3rds of the CONUS through the day Sun as positively tilted troughing digs into the S/W US. Due to the shallow nature of the sfc cold layer (of which it does not appear to extend above H850), the next cold front will lkly get 'funneled' through OK, and slowly wash through AR as it encounters the terrain of the Ozarks, causing the bndry to stall over the state.
A weak cold front will then move through tonight, followed by high pressure. High temperatures are expected to range from the upper 70s across the SC Lowcountry to the low to mid 80s across SE GA.
For tonight, high pressure sinks southward into western South Dakota, with winds calming a bit, but shifting around and becoming westerly. It is worth noting, that the high resolution and short range ensemble guidance hint at slightly warmer overnight lows. Good confidence in the extended time frame with respect to a period of dry and warmer but still continued below normal weather pattern.
328 AM CDT Sun Oct 25 2020 An upper level trough crossing the region early this morning will bring light snowfall to the CWA.
FGC Previous discussion: Synoptic Setup: Trough of cold air runs from northern Montana up into the Canadian Prairie Provinces. Farther west a large warm pacific ridge is butting up against the trough over the Pac NW coast. This is constantly pressing on the cold trough to move out. Sunday and Sunday night: Ridge to the West will topple over the front Range over Northern British Columbia and ALberta forming a chinook to the far northeast. The ridge should kick out the cold core trough aloft and start shallowing out the surface cold with a massive inversion forming.
High temperatures in the valleys will struggle to make it into the low-to- mid-40s today, and should stay in the 30s for the mountains. High pressure moving onshore into the PNW will return sunny skies and low winds back into the forecast through the rest of the weekend and into much of the week.
Concerns for the first snowfall include slick roads - especially areas that see any light freezing rain or drizzle as the changeover takes place. Currently, the upper level pattern features broad west to east flow with a Pacific trough digging into the northern Rockies as advertised. Over the SoCal region, a cut-off low feature appears to be developing as also progged by many of the deterministic solutions. Lower level 925-700mb lift appears to also be developing with a reinforcing push of Canadian high pressure spilling into Montana behind the aforementioned digging trough. Also, snow ratios may suffer which would keep some areas from seeing even the higher end snow totals.
This precipitation will generally stay a rain-snow mix during the day generally west and north of the US Hwy 151 corridor with more in the way of rain south and east of this highway.
309 AM MDT Sun Oct 25 2020 Currently, the upper level closed low is spinning just off the CA coast with the positively tilted trough moving down from the northern rockies. Along with the trough there is a jet that is pushing into the region positioning the right entrance region across the northern counties of our CWA. For areas along the I-25 corridor and Denver Metro amounts will range from 5 to 9 inches with the higher amounts closer to the foothills and north of I-70. For the current fire in Grand and Larimer counties in addition to the higher terrain areas we are continuing to expect 8 to 14 inches with locally higher amounts where convective snowfall is possible. Lows tonight will drop into the single digits with negative values in the high country and high mountain valleys.
08Z Surface analysis places a cold front from the Carolinas back through Southern Alabama and into the Central Gulf of Mexico. Models continue to indicate the upper level flow transitioning back to the southwest later tonight into Monday with rain chances gradually increasing across Northeast Arkansas as a cold front approaches the Mid-South and then becomes quasi-stationary as it becomes nearly parallel to mid-level flow aloft.
/NF/ In the wake of yesterday's low pressure system passing through, weak cold air advection will continue into the day today. This will help to reinforce the low stratus deck in place across the region and thus keep the diurnal temperature range "flattened" more than usual. Low-level clouds may begin to break up some by the evening as upper-level flow becomes southwesterly with a digging trough to our west, and as low-level begins to veer in advance of this system. slowly countering the cooler air in place currently.
/Issued 339 AM CDT Sun Oct 25 2020/ Temperatures a little warmer than yesterday are expected, though cloud cover has been very slow to clear. At this time, expect limited clearing across parts of eastern Oklahoma before clouds fill back in as a cold front approaches later today/tonight. Models are trending towards warmer temperatures over the next several days though the GFS still remains the coldest.
4" where deep tropical moisture has lifted northward into the southern FL peninsula from an inverted trough stretching northeast from TS Zeta. Highs will reach the low to mid 80s south of Orlando, where greater cloud cover and higher rain chances exists.
1010 AM EDT Sun Oct 25 2020 A weak area of low pressure will track up the east coast later today and tonight. Behind this system, a weakening cold front will push in from the Great Lakes Monday, then stall out south of the state.
A 1045 millibar arctic high pressure resides over central Montana and with lower pressure in southern Idaho, strong northerly winds have been observed over Lemhi County. Zooming out for a bird's eye view of the synoptic pattern, there is a very amplified upper level ridge over the northeastern Pacific with a subtropical moisture plume extending from Hawaii all the way north towards the Gulf of Alaska. Over the Northern Rockies,there is an anomalously cold trough above us. By Monday, the trough is expected to shift southeastward towards the Four Corners. This upper level warm front will moisten the mid-level layers of the atmosphere and potentially bring light snow through Monday night. This could be the impetus for freezing fog development each night, but confidence on when and where is low at this time.
There is quite a wind speed gradient across the area with winds 10 knots or less to the west, and in the high 15 to 20 knot range to our east. This is likely due to both mesoscale fluctuations and our eastern waters getting a bit more pinching between the low and a ridge located well out in the Atlantic. In addition, a subtle southern stream trough aloft will migrate eastward across Florida providing some support and increased ventilation. This is due to the upper level short wave trough moving out to the east, replaced by ridging.
Broad trough will be found across the state today. Trough and secondary surge of moisture exits the region tonight, with dry air behind this system.
Fog formation will be possible again tonight as the low-level cloud deck is forecast to lower. Upper level height rises are forecast to start the work-week as a deep trough digs in across the Desert Southwest. Bitterly cold air is forecast to dive southwards into the Rocky Mountains and Great Plains as this trough progresses eastward this week.
428 AM CDT Sun Oct 25 2020 In the wake of yesterday's low pressure system passing through, weak cold air advection will continue into the day today. This will help to reinforce the low stratus deck in place across the region and thus keep the diurnal temperature range "flattened" more than usual. Low-level clouds may begin to break up some by the evening as upper-level flow becomes southwesterly with a digging trough to our west, and as low-level begins to veer in advance of this system. slowly countering the cooler air in place currently.
Rain chances today look slim, even for the higher elevations today. Diegan Chattanooga Airport, TN 74 62 74 61 77 / 10 10 10 10 10 Knoxville McGhee Tyson Airport, TN 72 61 73 59 74 / 10 10 10 10 10 Oak Ridge, TN 72 61 72 58 74 / 10 10 10 10 10 Tri Cities Airport, TN 71 56 73 55 72 / 20 0 10 10 10.
An upper level trough crossing the region early this morning will bring light snowfall to the CWA.
1033 AM EDT Sun Oct 25 2020 A few scattered light lake effect rain showers will continue through midday to the southwest of Lake Ontario, otherwise high pressure will bring dry and cool weather for the rest of the weekend.