Aikyam-Lab/Synoptic-Bench huggingface dataset:
Also at the surface was a secondary cold front pushing southeast through Northeast Oklahoma with breezy westerly winds and drier air being transported into the region. Cloud cover associated with the low pressure system remained/continued spread back across much of Northeast Oklahoma and far Northwest Arkansas within the low level mean flow. the mid/upper level lows are expected to become more elongated from southwest to northeast over the Central Plains as the upper low center begins to lift northeast toward the Great Lakes region.
1145 PM CST Mon Jan 25 2021 A weak cold front will move through eastern Arkansas tonight. Today Through Wednesday As of 2030Z, mosaic radar imagery shows a broken line of showers with isolated embedded storms moving through eastern Arkansas as a cold front continues pushing through the area. Farther northwest, surface ridging is moving into the Plains with colder air poised to move into the area tonight. Statistical guidance shows a fairly narrow range between the lower and upper bounds for best/worst case scenarios, so overall confidence is higher, although some adjustments may be needed.
Reimer Low stratus persists over the lower elevations, and patchy fog is still present in far SE Montana. These cooler temperatures will help fog to quickly return to the entire area tonight and persist through Tuesday morning. The saturated layer in many areas of south-central Montana looks to be warmer than the DGZ, and hence may occur as freezing drizzle, but the saturated layer cools enough enough tomorrow morning to switch it all to snow showers and/or flurries. With all this being said, there's a very small chance for any precipitation to occur in the first place, so whether freezing drizzle or light snow occurs, impacts will be relatively minor. Vertz Ensemble consensus was for southwest flow to develop as an upper trough digs over the western United States.
1144 PM CST Mon Jan 25 2021 Updated for 06Z aviation discussion 06Z TAF discussion: Flight categories will continue to improve at area TAF sites overnight, in the wake of a cold front that's in the process of moving southeast through the region. This band will continue to shift southeast through the night as a weak cold front drops into the area. After the frontal boundary briefly exits the region to the west, it will begin to reverse its course as a warm front.
We are still getting a stratus overcast with upper level energy continuing to move across the area south of the upper low. A secondary low pressure system aloft was located over Arizona early this morning and will shift east across the central and southern Rockies today and across the plains tonight. There may be pockets of freezing rain where cloud ice is not present and may end as some light rain in the early afternoon over the eastern Ozarks, but the primary precipitation type should be light snow. Precipitation should come to an end before Wednesday evening with the main upper trough axis shifting east into the OH valley. Lows will be from the teens in central MO to the low 20s elsewhere.
Surface ridging across the area today will keep the area fairly quiet with winds shifting from northerly to east southeasterly this evening. This second shot of cooler air will bring temperatures back closer to normal.
/Issued 245 AM EST Tue Jan 26 2021/ A warm front currently remains entrenched across far NE Georgia this morning. Meanwhile, a cold front is moving across central Mississippi. Do expect the warm front to finally push north of the CWA this morning as the front approaches the state. Models continue to prog a low pressure wave developing across the northern Gulf and moving east along the stalled boundary on Wednesday. Strong storms have developed out ahead of the cold front across central Alabama. Any threat for stronger storms will shift southward later this morning and early afternoon across southern portions of the CWA ahead of the cold front. NListemaa Rain will be exiting at the start of the period as a cold front clears the area to the east.
245 AM EST Tue Jan 26 2021 A warm front currently remains entrenched across far NE Georgia this morning. Meanwhile, a cold front is moving across central Mississippi. Do expect the warm front to finally push north of the CWA this morning as the front approaches the state. Models continue to prog a low pressure wave developing across the northern Gulf and moving east along the stalled boundary on Wednesday. Strong storms have developed out ahead of the cold front across central Alabama. Any threat for stronger storms will shift southward later this morning and early afternoon across southern portions of the CWA ahead of the cold front. NListemaa Rain will be exiting at the start of the period as a cold front clears the area to the east.
One item to watch is whether we will see some freezing drizzle along and south of I94 as the DGZ tries to dry out today.
1033 PM CST Mon Jan 25 2021 A weak cold front will continue to move slowly to the southwest toward KPVW and KLBB in the first part of the TAF period, likely reaching both before sunrise. By Wednesday our deep westerly component aloft will shift to the northwest as an upper level ridge shifts over the FA. Main impact from this front will be lower clouds and just slightly cooler than average highs that will peak in the upper 40s to lower 50s.
1255 AM EST Tue Jan 26 2021 Weak high pressure will provide fair, dry weather through the first half of tonight, then conditions deteriorate as a storm passes over the region Tuesday with some wintry precipitation.
There is some speed and directional shear in the low-levels, but at this time helicities aren't excessive. A warm front that moved northward through Middle Tennessee overnight has become quasi-stationary near the TN/KY border, so most of Middle Tennessee is now in the warm, moist sector. A pre-frontal trough will swing through the mid state later this afternoon and evening, and this will provide some focus for the expected storms. Even though the bulk of the active weather will move across and exit the mid state overnight, the cold front won't actually arrive until Wednesday. ) After that, look for cooler temperatures the remainder of the week, with perhaps a weekend cold front representing our next chance of rain.
1028 PM MST Mon Jan 25 2021 Updated forecast for tonight to extend the coverage of fog for the high valleys west of the Laramie Range. Cold front analyzed on surface analysis from Cody to Rawlins to Laramie. upper ridge begins to build into southeast Wyoming with increasing 700mb westerly winds.
The cold front has moved to the coast and in its wake winds have become northwesterly across South Central Texas.
339 AM EST Tue Jan 26 2021 Rain and freezing rain this morning will transition to all rain this afternoon with ice accumulations expected across northern portions of the forecast area and in the eastern ridges this morning. The remainder of the week will be largely dry with cooler temperatures. Freezing rain mainly north of Pittsburgh by daybreak and in the ridges will slowly transition to all rain from south to north as winds veer south and surface temperatures warm. and more spotty areas to the south where surface temperatures are still near freezing have been handled with SPSs.
Snowfall looks to increase across southeast Utah and southwest Colorado this evening, as a closed mid level low pressure system associated with a larger trough across the west, moves into the Las Vegas area. By Tuesday afternoon, the low opens up and forcing begins to wane as the trough finally pushes east across the area. Some lingering light snow will occur over the divide Tuesday evening, but drier air will begin to filter in from the northwest as a ridge of high pressure moves into the Great Basin. Wednesday, flow aloft turns southwesterly as a deep trough briefly stalls along the Pacific Northwest coast.
Cloudy skies and above average temperatures will persist through tonight into tomorrow as humid southerly flow moves across the region, ahead of the advancing cold front moving in towards the forecast area from out of the north-northwest. Overnight low temperatures will be in the lower 60s and upper 50s. Approaching cold front will briefly stall in the vicinity of central and northern Georgia on Tuesday which will ensure warmer temperatures over the forecast area for this period along with showers and potential thunderstorms, with the heaviest activity occurring over southeastern Georgia and adjacent areas of northeastern Florida.
Despite the sunshine a very cold air mass hovers over the region with temps in the lower levels around -16C. This pattern stays fairly consistent with high pressure keeping things rather benign in the near term forecast. An upper level ridge begins to push in from west by midweek and warm advection slides in from the south.
1214 AM CST Tue Jan 26 2021 The latest observations show areas of light snow and freezing drizzle occurring across north central Kansas particularly along the I-70 corridor. Chances for lingering very light snow/freezing drizzle look to remain across central Kansas into the evening with shallow isentropic upglide as the colder air oozes south across the area. Next upper trof now moving through SoCal will move out across the central/southern Rockies on Tuesday before moving over the central/southern Plains. Clearing expected behind the departing upper trof for Wednesday though still cold with high temperatures well below seasonal climo.
(Today and tonight) On the synoptic scale, an amplified/progressive flow pattern continues with the next in a series of troughs passing through our region tonight. Wet bulb temperatures would support snow, but rates will probably be insufficient to saturate to the wet bulb temperature, and a slightly above freezing isothermal layer would be deep enough for rain. Again, low probability/light amounts, with some conditionality on ptype tied to not just ambient temperatures but rates and ability to fully saturate the low levels (unlikely).
As a weak upper trough shifts through our area tonight and Tuesday, can't rule out isolated snow showers or flurries, but chances at any one location will be very low. On Tuesday night, an upper trough will set up over the Pacific Northwest with a strong, moist southwest flow aloft developing. Warmer air in the southwest flow will start to work its way in by Wednesday afternoon, with showers changing to a rain/snow mix in the lowest valleys.
Tuesday night's weak wave will be followed by a transitory ridge Wednesday as a strong trough pulls southward just off the West Coast.
235 AM CST Tue Jan 26 2021 Visibilities have improved across the southern half of the CWA as winds and BL mixing have increased with the passage of the surface cold front. Temperatures will not rise much from their current values as the post-frontal air mass arrives from the northwest, maybe a few degrees warmer into the middle 40s in the northwest to the upper 50s in the southeast. While there may be a brief period of sleet or freezing rain on the onset of the precipitation, model soundings show this mainly to be a snow event. Skies will clear Wednesday night as chilly Canadian high pressure moves into the Midwest.
1026 PM MST Mon Jan 25 2021 Small chances for freezing precipitation have diminished enough that the chances have been removed from the forecast for the remainder of the evening. Latest analysis shows an upper low over SE Nebraska with a ridge building over Montana and Alberta. At the surface, low pressure is centered over southwestern Missouri with high pressure dropping southward from Saskatchewan into North Dakota. Bands of snow rotating northward around the low pressure system will bring some accumulating snow into south central and southwestern South Dakota with possibly up to an inch of accumulation over parts of south central South Dakota. There is also a chance of a little light freezing drizzle as the fog redevelops early this evening, with chances decreasing as the evening progresses.
Mild southerly flow will allow only a slow temp fall into the low and mid 60s by daybreak. On Tue, after morning clouds break, moderate S/SW flow will continue to bring unseasonably warm conditions to the area with high temps in the low to mid 80s all the way to the coast.
This band will continue to shift southeast through the night as a weak cold front drops into the area. After the frontal boundary briefly exits the region to the west, it will begin to reverse its course as a warm front.
As the warm and moist air continues to move over the cooler water nearshore, dense advection fog will continue to develop and affect coastal areas tonight, likely lingering near the coast through the day on Tuesday. The stalled front will serve as a focus for showers and few storms on Tuesday with a band of showers and storms lifting north from the coast during the evening hours on Tuesday as the boundary returns north as a warm front.
These storms haven't been severe, but the warm front is now situated through McMinn, Meigs, Rhea, and Bledsoe county so these do appear to be tapping into some low level instability. Showers and thunderstorms will move across the area over the next 4 to 5 hours ahead of a cold front. JB Chattanooga Airport, TN 56 67 46 58 31 / 80 20 10 40 10 Knoxville McGhee Tyson Airport, TN 46 65 42 55 30 / 80 30 10 40 50 Oak Ridge, TN 47 65 40 55 28 / 80 20 10 40 40 Tri Cities Airport, TN 49 62 38 54 27 / 90 40 10 50 80 TN.
Overnight into Tuesday, the elongated trough moves further inland, but with limited moisture. With this cloud deck and limited warming today, tonight's lows will be cool and below normal with the trough in place. The Spokane-Coeur d'Alene corridor, throughout the upper Basin, and into northeastern WA, snow from 1-3" is possible in the low lands and higher elevations may see up to 4-6" in 24 hours.
The best moisture and lift will still remain tied to the warm front our south however, which will likely limit any accumulations to around an inch or two for most, maybe up to three right along the lakeshore. Dry air will likely return quickly Tuesday afternoon, rapidly pushing out the remaining snow as the southern cyclone departs.
This was noted by the low relative humidities of 40 to 50 percent. The middle and end of the work week look to be dry as upper level and surface ridging move into and across the Midwest. As the ridging moves past the region, the upper level flow will turn to the southwest with a good model consensus that a system will advance toward the region for the weekend.
1033 PM CST Mon Jan 25 2021 (This evening through Tuesday) Temperatures this afternoon are a few degrees cooler than 24 hours ago, due to the cold front that moved through last night. Early Tuesday morning, a weak cold front will move down into the Big Country and likely stall over that region. A similarly strong 850 mb thermal ridge and warm southwest to west winds will result in highs Tuesday in the mid 60s to low 70s, except in the Big Country where there will be an east to northeast component to the winds behind the stalled weak cold front, bringing a little cooler air to that region (upper 50s/low 60s).
Evening water vapor imagery and objective analysis show a tightly wound upper low along the Nevada/Arizona border with a well defined arc of precipitation along a frontal band lifting across southern Utah. This has produced widespread snowfall and even dropped snow down to the lowest elevations around St George. This arc should gradually weaken with time as it lifts into central Utah, owing to weakening convergence into the band as the upper low continues east across northern Arizona. In the wake of this band precipitation across southern Utah should become more showery overnight toward Tuesday morning in proximity to the upper low.
207 AM CST Tue Jan 26 2021 Quite the longwave trough pattern across the western and central CONUS with a deep upper low helping to dump snow on the mountains of AZ this past few days. That same upper low will open up and shove eastward with passage to our north during the day today. Perhaps enough to lightly coat the higher peaks, but overall a mundane setup for snow.
Weak surface ridging builds in from the southwest behind the eastward moving surface cold front bringing a mild airmass. With the upper ridging and mild post- frontal airmass, temperatures remain about 15 degrees above normal.
(Today and tonight) A weak cold front will stall across the Big Country today but will have little effect, other then slightly cooler temperatures from yesterday, with highs in the upper 50s and lower 60s.
Today Through Wednesday Night An upper low is over the Rockies with southwest flow ahead of it through the Plains into the Midwest. The upper low moves into the Plains tonight and through Arkansas Wednesday. Ridging moves into the area Wednesday night. A secondary cold front continues to move through east Arkansas this morning. Moisture will return to the area tonight with a low pressure system. Rain should end in the east Wednesday afternoon and high pressure will continue to move into the state through Wednesday night. Above normal temperatures are expected today, 40s to 60s, then cooler and below normal Wednesday, 30s to 50s.
Finally beginning to see a south and eastward jog to the cold front and thus the push of the showers and storms south of the I-59 corridor. As we move into Wednesday the front will finally exit stage right by Noon and then we will see the upper level low swing through across the northern half.
700 AM EST Tue Jan 26 2021 Rain and freezing rain this morning will transition to showers as the morning progresses. The remainder of the week will be largely dry with cooler temperatures. Patchy freezing rain continues to plague areas generally along and north of I 76, as well as in the ridges, so headlines remain in effect. Warm advection via approaching low pressure will gradually improve the situation and pcpn will also diminish in coverage as that system passes.
Wednesday will turn milder w/ modest downslope warming underneath upper level ridging. The ridge axis will shift east thru the day, opening the door to southwest flow moisture and some orographic snow showers over the Beartooth/Absarokas.
Water vapour had upper low over western IA and a weak piece of lonely energy spinning over north central WY. These features will shift east today as upper low over AZ remains well south of the CWA. Tonight/Wednesday, upper level ridge builds toward the CWA. Aforementioned stationary front will transform into a warm front and inch eastward per increasing westerly component to low level flow.
On Wednesday, a trough will approach from the west. As the low stays situated off the West Coast, a moist southwest flow will advect over the area through the end of the week.
In the wake of yesterday's cold front, cooler temperatures can be found across much of Southeast Texas early this morning with lows ranging from the mid/upper 40s well inland to the mid to upper 60s at the coast. High temperatures are expected to reach the low to mid 70s for much of the inland areas with mid to upper 60s near the bays and beaches (if clouds become more extensive. Some models are developing some showers near the coast and offshore later today and on into tonight ahead of the next cold front, and that is where we will continue to carry some low rain chances and some patchy fog. Temperatures will cool back down later tonight (lows in the 40s inland and 50s coast) as the next and stronger cold front moves through the area.
On Wednesday a fast moving fairly sharp upper trough will move by in the afternoon and early evening.
With the approach of the second upper low (aka Las Vegas low mentioned above in the Synopsis), the threat for light snow will increase tonight as this system approaches from the SW. Further east, where snow cover is present, highs will struggle to get out of the lower 20s. Beginning Wednesday night, ridging will begin to amplify across the central CONUS.
The Florida Keys are still under the influence of a high pressure, located in the Western Atlantic. The anticyclone started to move off to the east overnight, causing the gradient to relax.
/19/ Today and Tonight: A cold front will continue to make its way southeast through the forecast area this morning, before stall south of the CWA later today. With convection coming to a quick end in its wake, drier air will steadily filter south into the CWA as weak high pressure builds into the region.
Widespread dense fog has developed behind the clearing of the low stratus. Visibilities have improved across the southern half of the CWA as winds and BL mixing have increased with the passage of the surface cold front. Temperatures will not rise much from their current values as the post-frontal air mass arrives from the northwest, maybe a few degrees warmer into the middle 40s in the northwest to the upper 50s in the southeast. While there may be a brief period of sleet or freezing rain on the onset of the precipitation, model soundings show this mainly to be a snow event. Skies will clear Wednesday night as chilly Canadian high pressure moves into the Midwest.
Afterwards, high pressure begins to vacate as a larger system to our south spins through Illinois.
The longwave trough across the westerns CONUS is in the process of advecting eastward and will continue to do so over the next few days as the upper level pattern becomes more progressive. The wave will sharpen as it moves into the High Plains this afternoon. Kinematic forcing in the left-front quadrant of a leading 160-kt jet streak rounding the base of the trough and increasing mid- level isentropic ascent ahead of the H500 low will serve to initiate the development of snow in western Kansas this afternoon, moving into eastern Kansas quickly by this evening. The forcing pushes east by 12Z Wednesday and the snow should wane quickly once the upper trough axis passes through before 15Z. The pattern takes a quieter and warmer turn for the end of the week.
349 AM CST Tue Jan 26 2021 Cyclonic flow aloft continues this morning, with a closed low over Manitoba expected to slowly push east through the short term. At the surface, persistent arctic high pressure is centered over Manitoba, with northeast surface winds but weak flow in the mid levels across the forecast area. Ridging starts to build over the northern Rockies on Wednesday in response to a deepening trough over the eastern Pacific.
346 AM CST Tue Jan 26 2021 Today and Tonight: A cold front will continue to make its way southeast through the forecast area this morning, before stall south of the CWA later today. With convection coming to a quick end in its wake, drier air will steadily filter south into the CWA as weak high pressure builds into the region.
Since the entire FA has stayed cloudy, temperatures have been warmer than anticipated.
An upper ridge on Wednesday will moderate temperatures somewhat but it will take a warm front Wednesday Night to push the cold air to the east.
Tonight, a quick moving mid-level trough which resides over the western Rockies this morning, will move into the region. Highs Wednesday will only reach the lower 20s to lower 30s making it one of the coldest days thus far this winter. Conditions look dry out with a warming trend through the end of the week as upper level ridging building across much of the central CONUS.
The range in model guidance is anywhere from 15 below zero to 5 above zero for overnight lows, so the current forecast is slightly on the warmer side of the model spread. We can not rule out freezing rain, but as of now the confidence was too low to even mention the chance of freezing rain in the forecast. No changes were made to the model blended forecast guidance given the higher uncertainty in this type of weather pattern. Forecast confidence usually goes down anytime there is convection associated with the development of a synoptic cyclone.