Aikyam-Lab/Synoptic-Bench huggingface dataset:
Some patchy fog/freezing fog will also be possible mainly north of I-40 tomorrow morning where skies clear this evening. a mid-level ridge will build into the area which will allow temperatures to rebound into the upper 40s - mid 50s under sunny skies. Highs could remain a little cooler in areas that received the greatest snowfall that will require substantial melting tomorrow.
The cold front is currently moving across Middle TN this morning, shifting winds from the west at up to 10 mph. Farther east, temperatures will hold steady in the lower 40s, eventually trending downward slightly this afternoon as the front arrives. No accumulations are anticipated give the above freezing temperatures.
Most precipitation and forcing for broad-scale ascent will have left the area by this evening as the trough axis moves to our east. However, residual moisture along the western flank of the upr trough, continuing CAA and slight terrain-induced uplift may result in some flurries along the plateau in middle TN. Better likelihood of any snow flurry activity will exist farther north in TN, but a few flurries could not be ruled out along the higher terrain in Franklin County, TN. Due to the low likelihood for our area, this was not included in the current forecast, but will need to be monitored today. An upstream vort max will move quickly into the region on the heels of the exiting trough and carve out a broader trough across the region on Thursday.
Nudged today's temperatures for portions of NW Oklahoma towards the ECWMF, and manually lowered the high for Woodward to 26 deg F.
Then, a cold front is expected to pass through the area later this afternoon through the overnight. This is where the highest PoPs are confined to, up to 60-80%. Then, a cold front will pass through the area later this afternoon into the overnight. Showers and scattered thunderstorms are expected, with the highest coverage from KMLB northward. Then, a cold front will pass through east central Florida and its adjacent waters later this afternoon through the overnight. The front will weaken/slow as it passes southward, with the highest PoPs north of the Cape (~50-60%).
349 PM EST Wed Dec 16 2020 Another very warm December afternoon for the Florida Keys, with temperatures universally around 80 degrees and dew points in the lower 70s. Water vapor imagery depicts a vigorous trough pushing through the Southeast and Mid-Atlantic, with cyclogenesis occurring just offshore of the Carolina coastline. A trailing cold front associated with this system is producing a pretty healthy squall line extending from the south-central Gulf of Mexico northeastward across Central Florida.
However, these winds will shut off as a deep trough swings south of us over the 4 corners region. A weak cold front associated with this trough will pass over the area Thursday evening, bringing with it a small chance for at first, a rain-snow mix, then all snow by Thursday night. Also associated with this upper trough is light mountain snow, with a few inches possible.
1008 AM MST Wed Dec 16 2020 Current surface analysis shows low pressure over southeast SK, with trough stretching southward across far western ND into the Black Hills area. Temps range from mostly teens to the east of the Black Hills to the lower 30s from parts of northeast WY to far western SD. Winds are currently light from the south to the east of the trough, with increasing westerly winds behind it to the west.
Winds will veer to the south to southwest early tomorrow afternoon in response to a developing surface lee trough. This change to a southerly component, along with upper level ridging, will allow temps to warm back into the 50s and 60s.
Surface temperatures in this area are a few degrees above freezing, so no accumulation or travel impacts are expected. Across SE MO, S IL, and much of W KY, lows will fall into the lower to middle 20s. More solar insolation will allow temperatures to reach the lower 40s across SE MO, SW IL, and W KY Purchase.
1123 AM CST Wed Dec 16 2020 Fresh snow cover, light winds, and small dewpoint depressions will support patchy freezing fog overnight into this morning across the region. Since temperatures are below freezing, patchy slick roads are likely. Could see additional patchy freezing fog tonight into Thursday morning, mainly across eastern/southeast KS, possibly as far west as I-135.
High temperatures in the low to mid 50s are expected across the area on Thursday.
Ridging aloft will build over the region for Thursday, with dry conditions expected.
Thursday: Warmer temperatures with upper ridging is anticipated, although combo of moist ground/linger snow will curb temperature recovery.
The cold front is currently moving across Middle TN this morning, shifting winds from the west at up to 10 mph. Farther east, temperatures will hold steady in the lower 40s, eventually trending downward slightly this afternoon as the front arrives. No accumulations are anticipated give the above freezing temperatures. Mainly IFR cigs expected today as a low pressure system crosses the area with widespread showers. Winds will be mainly SSW under 10KT through early this morning, becoming WNW near 10KT as the low pressure center moves to our east in the afternoon.
923 PM EST Wed Dec 16 2020 Low pressure will track away from the Delmarva tonight. High pressure will reside well to the north over Quebec.
221 PM MST Wed Dec 16 2020 Warm, westerly winds with mostly sunny skies have blown the high temperatures around noon today by several degrees for many locations. An upper ridge slides across the area through Thursday for continued warmer downslope conditions. However, a Pacific low pressure system will sweep across the state by Thursday night.
Lows tonight will range mostly in the 30s area-wide with right at freezing for the interior sections towards daybreak. Thursday is expected to be cool with highs in the lower to mid 50s despite mostly sunny skies.
538 PM CST Wed Dec 16 2020 Low level clouds have been gradually clearing out as a longwave trough passes through the region.
The attendant surface cold front is well to our east with cold advection and overcast skies persisting across the Mid-South this afternoon. Expect skies to gradually clear late tonight with slightly warmer temperatures by tomorrow afternoon.
Temperatures will drop into the low to mid 20s for most areas. The exception will be areas with greater snow pack, and overnight lows could fall into the low teens (especially over NW Oklahoma). A mid-level ridge is prog'd to reach the plains tomorrow resulting in mostly sunny skies. Tomorrow will be roughly 10 to 15 degrees warmer than today, with coolest highs expected over NW Oklahoma.
/issued 204 PM CST Wed Dec 16 2020/ An upper trough responsible for our the increased winds yesterday is quickly moving eastward and out of Texas. Weak ridging behind this trough will improve our temperatures todays as highs will be mostly in the 50s with a few 60s along the Pecos and Rio Grande rivers. Increasing cloud cover on Thursday will help keep temperatures warmer Thursday night.
/GG/ High pressure ridge at the surface over TX is building eastward behind the exiting storm system. That northwesterly wind will usher in cooler and drier air. As a result, overnight lows will drop to below freezing, ranging from the upper 20s to right around the freezing mark.
A cold front currently near the FL Big Bend will move across east central Florida, clearing the Treasure Coast just past daybreak Thursday. The cold front will have slowed sufficiently to still be draped across or just south of the Treasure Coast by daybreak on Thursday. At the surface cool high pressure building into the area will keep a dry and cool regime in place. There may be some isolated frost potential across some normally cooler and wind sheltered portions across the I-4 corridor, but will not include in the digital forecast just yet due to low certainty. A cold front will push southward through east central Florida and the local waters through Thursday morning front while slowing.
308 PM CST Wed Dec 16 2020 Low level clouds have been gradually clearing out as a longwave trough passes through the region.
The first of which involves slightly cooler afternoon highs, and the second of which involves the potential for fog and freezing fog overnight. With cloud cover inhibiting mixing and evaporation of yesterday's precipitation, there is a slight possibility of fog and freezing fog developing that may become a concern for any overnight travel across bridges and elevated overpasses. Beyond tonight, the forecast impacts become simpler as clouds gradually dissipate and clear skies allow for mixing to highs in the 50s and uninhibited radiational cooling by tomorrow night with lows back to near or below freezing.
Other locations will receive light precipitation and some of that could fall as rain, snow or even a few pockets of light freezing rain.
Temperatures trend warmer at lower elevations with increasing southwest winds.
Clearing skies will also bring cooler overnight lows tonight, generally in the teens. With clear skies and westerly winds mixing down warmer air, temperatures have risen nicely across the area and are as much as 20 degrees warmer than yesterday. We will be in between two systems tonight/tomorrow as transitory upper-level ridge moves in.
A bit of a warm up in temperatures Thursday afternoon as an upper level ridge passes across the area.
649 PM EST Wed Dec 16 2020 Flurries and patchy freezing drizzle will linger through the overnight and into the day Thursday.
A storm with a history of rotation off the coast weakened before rapidly strengthening as it moved through Central Pinellas, continuing over the Bay near the Howard Frankland Bridge. Winds will become northwest later tonight as a cold front moves through. A cold front will move through later tonight with winds shifting out of the northwest.
334 PM CST Wed Dec 16 2020 Upper level ridging will translate eastward into the central CONUS Thursday. This is ahead of an upper trough that will be moving onto the west coast. Winds will turn south on Thursday as the low deepens across northeast WY. As a result, highs Thursday will probably not be any warmer than today with lower to mid 40s across the area. The upper trough dampens and remains positively tilted as it moves toward the area Thursday night.
Low pressure will bring a chance of showers across the southern Sierra and much of the Great Basin region Thursday, along with gusty winds for the Mojave Desert.
Radar data suggests some light snow continues to fall over the higher terrain, and the expectation is for light snow showers to continue at or above 9-10kft in the northern mountains early this evening. Short term guidance indicates drying in the low and mid levels by the 3z timeframe this evening up north, and any lingering snow showers should come to an end. Low stratus may also scatter out as well by midnight, especially along the lower US 40 corridor. A weak 500mb ridge axis will pass early on Thursday morning.
We reduced QPF on the mountain ridges around the Indian Peaks as models are likely overestimating the remaining snowfall potential this evening as they have been doing all day. The upper ridge will continue to advance over the Rockies tonight and Colorado should be under the ridge axis by morning. The next trough will be advancing to the Rockies through the day.
Forecast remains on track with overall snow intensity diminishing with eastward shift of the upper trough/jet support. The eve update generally involved some cosmetic adjustments as widespread snow continues in response to an encroaching upper trough which features an impressive coupled jet structure. Patchy freezing drizzle will linger, but ice accumlation greater than a trace is not anticipated in that time frame.
The valley looks to be on the edge of the clearing so has the highest range of possible outcomes for the lows tonight.
530 PM CST Wed Dec 16 2020 At 130 PM, weather conditions were fairly quiet across the area underneath a lobe of surface ridging, though an influx of low- level moisture from the east was leading to partly to mostly cloudy skies. Lows are expected to drop into the upper teens to low 20s tonight, though if things end up clearer than expected, temperatures could fall into the low teens for some. Highs Thursday should be mainly in the upper 20s to low 30s, perhaps a tad cooler if clouds linger longer than anticipated.
514 PM CST Wed Dec 16 2020 Upper level ridging will translate eastward into the central CONUS Thursday. This is ahead of an upper trough that will be moving onto the west coast. Winds will turn south on Thursday as the low deepens across northeast WY. As a result, highs Thursday will probably not be any warmer than today with lower to mid 40s across the area. The upper trough dampens and remains positively tilted as it moves toward the area Thursday night.
Lows tonight under clearing skies expected to drop back into the middle to upper teens for many with the little to some snowpack areas being a touch warmer in the low 20s. High pressure continues to build eastward across the four corners, while low pressure strengthens over the Southeast with the associated cold front extending through Alabama. Conditions are expected to become unstable as an upper level ridge propagates eastward towards the Midwest.
957 PM CST Wed Dec 16 2020 At 130 PM, weather conditions were fairly quiet across the area underneath a lobe of surface ridging, though an influx of low- level moisture from the east was leading to partly to mostly cloudy skies. Lows are expected to drop into the upper teens to low 20s tonight, though if things end up clearer than expected, temperatures could fall into the low teens for some. Highs Thursday should be mainly in the upper 20s to low 30s, perhaps a tad cooler if clouds linger longer than anticipated.
222 AM CST Thu Dec 17 2020 High pressure shifting across Illinois today, will bring quiet weather and cool temperatures.
We do have an interesting synoptic wave setup over the Central/Eastern CONUS though, with a positively tilted low-level trough axis at h850 across GA at 12Z but the trough axis around h500 back across the Ozark and ArkLaTex region that wouldn't pass through the region until later tonight around 00 UTC. The low-level trough will help keep the thicker low-level clouds in place in through the early morning.
1235 AM EST Thu Dec 17 2020 Flurries and patchy freezing drizzle will linger through the overnight and into the day Thursday.
The I-79 corridor, Pittsburgh included, is looking at a possible inch of additional accumulation while locations farther east from Clarion southward through Indiana and Greensburg may easily pick up an additional 3 or more inches of snowfall before the higher rates end in the next few hours. By daybreak, dry air will begin to move into the dendritic growth zone such that any remaining dendrites will turn into an area of freezing drizzle. Highs will range from around 30-35 for most of the area and few degrees colder in the higher elevations of the Allegheny Mountains.
Stumpf (Issued 140 PM CST Wed Dec 16 2020) Tonight through Thursday night: High pressure the dominating influence this period. Heading into Thursday night the lower level flow becomes more southwest and takes any lake effect precip off more to the northeast of the area.
Should skies become clear a little more quickly than currently anticipated, then portions of Northwest Alabama could drop into the low to mid 20s, but this is not a likely scenario. Depending on cloud trends, highs will only reach the lower 40s in valleys on Thursday, with upper 30s atop the Cumberland Plateau/Sand & Lookout Mtn areas). Lows should dip into the lower to middle 20s Thursday morning.
Despite the colder air, a large canopy of low stratus from the TN valley into the state of LA would help to offset how low temperatures get and have made an upward adjustment to night-time lows, now in the lower to mid 30s interior to 37 to 41 coast.
It is likely that southwest Indiana, most of the northern two thirds of the west Kentucky Pennyrile region and a small part of southeast Illinois will remain under cloud cover, while the remainder of the area, influenced by the approaching high pressure ridge, remains clear overnight. Surface temperatures in this area are a few degrees above freezing, so no accumulation or travel impacts are expected. Across SE MO, S IL, and much of W KY, lows will fall into the lower to middle 20s. More solar insolation will allow temperatures to reach the lower 40s across SE MO, SW IL, and W KY Purchase.
As for the high terrain, expecting orographic lift to initiate which will favor additional accumulations above 3500ft. DGS Chattanooga Airport, TN 43 27 49 30 49 / 10 0 0 0 20 Knoxville McGhee Tyson Airport, TN 40 26 45 29 49 / 10 0 0 0 20 Oak Ridge, TN 41 25 45 28 48 / 10 0 0 0 20 Tri Cities Airport, TN 39 25 41 26 47 / 10 10 0 0 10.
Otherwise forecast remains on track with cooler temps tonight and tomorrow.
KBOI 00Z upper air sounding revealed warm air aloft, with wet bulb temperatures above freezing for roughly 2000 ft AGL. This will allow precipitation to fall as rain in the lower valleys. While mild air has mixed down to the surface near Boise this evening, cold air with temperatures near freezing in the lower Treasure Valley, Weiser River Basin, and portions of northern Malheur and Harney counties will be slower to mix out tonight, and pockets of freezing rain are expected overnight into early Thursday.
359 AM EST Thu Dec 17 2020 Low pressure will linger over the region today, keeping conditions cloudy and cool with some lingering light precipitation.
As for the high terrain, expecting orographic lift to initiate which will favor additional accumulations above 3500ft. A upper wave and associated cold front will continue traversing atop the region through tonight, with all sites firmly behind the front by daybreak Thursday. CDG Chattanooga Airport, TN 33 43 27 49 30 / 10 10 0 0 0 Knoxville McGhee Tyson Airport, TN 34 40 26 45 29 / 40 10 0 0 0 Oak Ridge, TN 33 41 25 45 28 / 30 10 0 0 0 Tri Cities Airport, TN 33 39 25 41 26 / 70 10 10 0 0.
257 AM CST Thu Dec 17 2020 Weak upper troughing passing over the central CONUS this early morning, while the strong nor'easter continues to impact the New England states. An additional upper low is entering the northwest coast, spreading mid level moisture on top of an upper ridge present within the mountainous terrain. Cannot rule out patchy dense freezing fog in low lying areas, but otherwise the haze should lift shortly after sunrise.
205 AM CST Thu Dec 17 2020 A fairly benign pattern will occur over the next several days with weak ridging establishing through the end of the week with rebounding temps back to near and above normal today and tomorrow.
/JNE/ Prior discussion below: High pressure ridge at the surface over TX is building eastward behind the exiting storm system. That northwesterly wind will usher in cooler and drier air. As a result, overnight lows will drop to below freezing, ranging from the upper 20s to right around the freezing mark.
Have extended the High Wind Warning for Arlington/Elk Mountain thru 18z Thursday. Lows tonight under clearing skies expected to drop back into the middle to upper teens for many with the little to some snowpack areas being a touch warmer in the low 20s. High pressure continues to build eastward across the four corners, while low pressure strengthens over the Southeast with the associated cold front extending through Alabama. Conditions are expected to become unstable as an upper level ridge propagates eastward towards the Midwest.
334 AM EST Thu Dec 17 2020 With the recent cold front moving into southern Florida, northwesterly low level flow today will setup strong cold air advection.
208 AM CST Thu Dec 17 2020 Cold ground, light winds, and smallish dewpoint depressions will support patchy freezing fog through early to mid-morning across eastern/southeast KS. Since temperatures are below freezing, patchy slick roads are possible.
1044 PM EST Wed Dec 16 2020 A low pressure system is currently trekking northeast along the eastern seaboard. A trailing cold front extends south and southward across central Florida and the southeastern Gulf of Mexico. As such the cold front has yet to move into our region. Southeast winds across the island chain is keeping temperatures in the mid 70s with dew points in the lower 70s, keeping it quite muggy. Given the low level steering flow (925-700 mb mean flow) from the southwest, showers that develop will have a tendency to stay offshore. Otherwise, the cold front to our north and northwest will slowly edge southward tonight and into Thursday, eventually passing through in the late morning and early afternoon hours. Then winds shift to the northwest in the afternoon and sharply increase behind the cold front.
1100 PM CST Wed Dec 16 2020 Low level clouds have been gradually clearing out as a longwave trough passes through the region.
1114 PM CST Wed Dec 16 2020 Upper level ridging will translate eastward into the central CONUS Thursday. This is ahead of an upper trough that will be moving onto the west coast. Winds will turn south on Thursday as the low deepens across northeast WY. As a result, highs Thursday will probably not be any warmer than today with lower to mid 40s across the area. The upper trough dampens and remains positively tilted as it moves toward the area Thursday night.
Overall, this should result on only minor wording changes in the zone text product as all areas are expected to reach near or below freezing by daybreak with skies continuing to gradually clear over the next several hours.
400 AM EST Thu Dec 17 2020 Cold temperatures and upslope flow across the forecast area will lead to ongoing drizzle, snow flurries, and possible some freezing drizzle today and tonight. Any freezing drizzle will likely only persist through 14 or 15Z today, before moving out of the area.
This upper ridge axis will be centered over the area overnight Thursday night. Temperatures will dip into the low to mid 20s in the eastern Ozarks and the low 30s over the western CWA.
With temperatures below freezing, fog that is dense enough (generally below one-half mile) could create slick spots on area roadways. Warmer temperatures are anticipated today with more sunshine in the offing.
248 AM EST Thu Dec 17 2020 An upper level trough will move through the area today and result in considerable clouds and cool temperatures. A high pressure ridge will build in behind the trough from the southern Plains into the weekend.
1231 AM EST Thu Dec 17 2020 IFR/MVFR ceilings are beginning to spread over area terminals as the cold front works south through the Florida Peninsula. A storm with a history of rotation off the coast weakened before rapidly strengthening as it moved through Central Pinellas, continuing over the Bay near the Howard Frankland Bridge. A cold front will move through later tonight with winds shifting out of the northwest.
/issued 205 AM CST Thu Dec 17 2020/ A fairly benign pattern will occur over the next several days with weak ridging establishing through the end of the week with rebounding temps back to near and above normal today and tomorrow. Trough axis will quickly cut southeast into the northern half of the Panhandle, eventually ejecting eastward into the Red River valley.
Forecast highlights in the short term period will be another mild day today, followed by a cold frontal passage tonight through Friday morning. Active flow pattern continues with the S/WV ridge moving quickly eastward across the area today, followed by another S/WV trough/cold frontal passage tonight into Friday. along the cold front, so went with higher POPs for this feature.