Aikyam-Lab/Synoptic-Bench huggingface dataset:
Satellite imagery shows broken low/mid level clouds across a good portion of the forecast area early this morning as the trough axis slowly moves to the north/east. Precipitation seems to be dropping off a little sooner than expected with accumulations looking weak even in the higher terrain. Northerly flow aloft moves in on the back side of the trough today keeping us cool through the short term. Outside of extreme southern Utah, much of the forecast area will struggle to see daytime temperatures above freezing today with similar conditions expected for Wednesday.
/22/ Today and Tonight: Early morning surface analysis had a >1020mb high just off the Florida peninsula's east coast that was ridging back across the peninsula and northern Gulf of Mexico while a cold front was noted dropping southeast over southeast Missouri and northwest Arkansas. Surface dewpoints will climb into the low to mid 60s areawide by this evening along with PWATs just shy of an inch and a half. As the cold front approaches our CWA today and becomes nearly parallel to the flow, it will slow and model consensus doesn't move the cold front into our CWA until after midnight tonight. Although temperatures will top out in the low to mid 70s again today, temperatures will be back into the 60s by the time the cold front arrives.
Given the high QPF values for Wednesday afternoon and evening, we'll be keeping an eye on observed rainfall amounts over the next 24 hours.
Dry weather will continue through the rest of the short term period as a 1030 mb high pressure system settles in this morning and exits early Wednesday. Skies should be mostly clear across the board, helping to boost confidence for warmer-than-Tuesday readings and above average values on a whole.
Weak high pressure ridging across the area. Southerly surface flow today, as east central Florida will be on the western periphery of a high pressure drifting into the Atlantic. Weak high pressure ridging across the area. High pressure over the western Atlantic will produce southerly flow and warming conditions.
In the bigger picture, a large upper trough axis is xpcted to drop into the SW states, while a sfc wave develops over the srn Plains and begins to lift NE. In addition, a diffluent flow pattern aloft ahead of the upper trough pattern may support multiple rounds of locally heavy rainfall from Tue night into early Thu and translate into a threat of localized or flash flooding. The severe/flooding threat should begin to diminish Thu morning with the passage of the cold front, although lingering showers will continue thru the day as the upper trough axis begins to pivot thru the SE states. Temps are xpcted to remain unseasonably warm into Thu, although cooler/drier air will begin to move into NW AL late Thu in the wake of the frontal passage.
529 AM CST Tue Feb 4 2020 Low CIGs have moved into the region following the passage of a strong cold front. The upper level trough was slowly churning across the Intermountain West and appears to already have a closed off height contour over Colorado. This will continue through Wednesday afternoon to a varying degree on the downstream side of the upper trough. Before the main snow event occurs tonight, a cold front was currently moving through the area much quicker than anticipated. A quick end to the event will occur late Wednesday afternoon with the trough axis moving overhead.
334 AM MST Tue Feb 4 2020 Satellite imagery shows broken low/mid level clouds across a good portion of the forecast area early this morning as the trough axis slowly moves to the north/east. Precipitation seems to be dropping off a little sooner than expected with accumulations looking weak even in the higher terrain. Northerly flow aloft moves in on the back side of the trough today keeping us cool through the short term. Outside of extreme southern Utah, much of the forecast area will struggle to see daytime temperatures above freezing today with similar conditions expected for Wednesday.
856 AM EST Tue Feb 4 2020 Moisture will slowly increase across the area today as a low pressure system approaches from the lower Mississippi Valley.
/Issued 347 AM CST Tue Feb 4 2020/ Cold front moving into southeast Oklahoma/northwest Arkansas early this morning, currently located near a Clayton, Fayetteville line. Otherwise, cold/breezy conditions expected over the area today behind cold front. In addition, point soundings suggest the potential for sleet and/or freezing rain to spread into southeast Oklahoma Wednesday morning. Forecast ice amounts have increased to around a tenth of an inch across aforementioned area, including the higher terrain areas of northwest Arkansas. Heavier snow will begin to lift northeast of the area Wednesday evening as upper trough axis begins to shift east of the region.
100 PM EST Tue Feb 4 2020 Moisture will slowly increase across the area as a low pressure system approaches from the Lower Mississippi Valley.
In addition, a diffluent flow pattern aloft ahead of the upper trough pattern may support multiple rounds of locally heavy rainfall from Tue night into early Thu and translate into a threat of localized or flash flooding. The severe/flooding threat should begin to diminish Thu morning with the passage of the cold front, although lingering showers will continue thru the day as the upper trough axis begins to pivot thru the SE states. Temps are xpcted to remain unseasonably warm into Thu, although cooler/drier air will begin to move into NW AL late Thu in the wake of the frontal passage.
Upper trough over the desert southwest to continue deepening. Mid/Upr troughs draw further east, helping to spin up fairly good SFC/LL low. This low rides up frontal boundary on Wed, eventually crossing right over the mid- state Wed evening. As SFC wave moves north and drags our front east Wed night, heavy rain is expected to vacate by early Thu morning, although it will take into Fri morning for the upper trough axis to pass.
1014 AM EST Tue Feb 4 2020 Moisture will slowly increase across the area today as a low pressure system approaches from the lower Mississippi Valley.
Any brief change over (light freezing rain or sleet) from say Marble Hill, MO to Mount Vernon, IL late tonight will be of little consequence, if it happens at all. To our west, an upper level H5 trough will move east across the naiton's mid section. On the back of the system Wednesday into Wednesday night, cannot rule out a period of light freezing rain or sleet, or even trace drizzle/freezing drizzle from SEMO into southern IL. It will likely be somewhat breezy Wednesday into Wednesday night as well, as the low deepens to our south and east.
CD Chattanooga Airport, TN 60 67 58 63 38 / 80 90 90 80 60 Knoxville McGhee Tyson Airport, TN 58 68 58 64 38 / 60 90 90 90 80 Oak Ridge, TN 58 65 57 63 35 / 80 90 90 90 70 Tri Cities Airport, TN 53 65 56 63 36 / 80 90 90 90 90.
Cold front should be moving into northern parts of the region between 4-6 pm, so noted a quicker temp drop there during that time period. Warm, moist air moving over the cooler shelf waters has allowed for some sea fog to develop.
But main issue is the northern stream 500 mb trough axis moving thru central ND into S Manitoba. Some moisture with this trough axis and this will move thru the area this morning. High pressure will be over the area today with light winds. Not as cold tonight as winds turn southerly 5 to 12 kts, then much warmer Wednesday as southwest winds increase into the 10-20 kt range by aftn.
121 PM MST Tue Feb 4 2020 A departing mid-level trough will give way to NW flow through the remainder of this week. However, a few weak short wave troughs moving through the region could still bring some snow showers to Northeast Montana.
Mid-levels remain saturated, however, there has been considerable dryness in the low levels which has inhibited snowfall across the region. An upper trough will move through the area Wednesday with northwest flow setting up over the region late in the afternoon.
Winter precipitation will move into the area late tonight, with a mix of sleet, snow and freezing rain. 12Z data suggests an period of freezing rain/sleet before an eventual changeover to snow.
Strong, but positively-tilted, trough was centered across western Colorado at midday. Modest lift and forcing ahead of the trough axis continues to produce scattered light snow showers or flurries, with trace dustings at most locations. Stratus clouds will persist through this afternoon through tonight, as trough axis continues to approach from the west. Wednesday will remain plenty cold, with the positively-tilted trough axis not arriving until about 6 pm, and the airmass remaining very cold. Despite the return of sunshine, temperatures will struggle to reach freezing in the afternoon.
Weak SFC/LL boundary remains just to our northwest as upper trough across the desert southwest continues to dig.
1058 AM CST Tue Feb 4 2020 Early morning analysis showed upper level ridging over the eastern CONUS with troughing over the Rockies, leaving the forecast area under southwest flow aloft. At the surface, high pressure continued to build into the area with a tight pressure gradient leading to gusty northerly winds. This continued to usher in some cooler air, though widespread mid to high level clouds were keeping temperatures in the 20s to lower 30s. Farther northwest in central Minnesota under clear skies, temperatures had dipped into the lower teens and single digits. Otherwise, high pressure will continue to build in through the day and lead to quiet weather.
This will keep us in a cold air advection regime, though weakening into this evening as the center of the high approaches and winds slacken.
Southerly flow to increase further Wed night-Thu with high dew point airmass advecting into the area over cooler shelf waters for the potential sea fog near the coast especially in NE Gulf.
Tonight and Wednesday The latest RAP analysis and satellite/radar imagery show arctic high pressure centered over the northern Plains and a stalled front over the Ohio Valley. The arctic high pressure will become centered across the region. High pressure will remain centered across the region. Mid and high clouds should exit for a time during the morning before they return in the afternoon ahead of the developing cyclone over the southern Plains.
Surface temps from the West Texas Mesonet show the entire area is just at or below the freezing mark so any liquid that does fall out of the sky is expected to be snow from this point forward. Our stronger round of more widespread precipitaion will begin to take hold this evening through tomorrow midday as embedded disturbances round the base of the upper level trough and move across the CWA.
1017 AM CST Tue Feb 4 2020 The forecast has been updated to reflect the current position of the cold front and the rain that has developed over the Permian Basin. Temperatures will remain above freezing through the afternoon in these areas so we should just see wet roads.
1021 AM MST Tue Feb 4 2020 Water vapor shows the upper trough moving from the Great Basin into the CO/WY Rockies. Surface analysis shows high pressure centered pushing into ND from Canada. There is a little bit of freezing fog across parts of northeast WY. Temperatures today will be in the 20s to low 30s, then slightly warmer on Wednesday, with highs in the mid 20s to mid 30s.
As the high pressure moves eastwards, the pressure gradient tightens and will create some breezy winds over the area.
Cold front will continue to sag south toward the mountains this afternoon with winds shifting to the northeast at all terminals. /issued 1017 AM CST Tue Feb 4 2020/ The forecast has been updated to reflect the current position of the cold front and the rain that has developed over the Permian Basin. Temperatures will remain above freezing through the afternoon in these areas so we should just see wet roads.
The potential for single digit readings overnight is there with the upper trough over the region and H85 temps around -10C. The large 500mb trough that is currently centered from northern Canada through ND/CO/AZ and impacting much of the continuous U.
318 PM EST Tue Feb 4 2020 Cold anticyclonic flow continues to usher in increasingly cooler air from the north and establishing an elongated baroclinic zone from central Texas into portions of New England. This frontal zone will serve as the focus of multiple waves of low pressure as the trough over the 4-corners region lifts northeast during the latter half of the week.
Early this afternoon the freezing line has made it into southeast Kansas into central Missouri, with rain showers mainly across the central and eastern Ozarks into portions of central Missouri. Will see this freezing line slowly work its way southeast tonight, setting up somewhere near the highway 60 corridor by morning. With warm ground and roads and temperatures only settling into the upper 20s to lower 30s impacts will be minimal, concentrated on elevated objects, bridges and untreated roads.
As the gradient flow between the approaching front and departing high pressure builds on Wednesday, wind speeds will be stronger and some coastal areas could see some wind gusts on Wednesday afternoon in the 20 kt range.
With weaker winds, expect another cold night tonight with freezing temperatures expanding west of the mountains.
1215 PM CST Tue Feb 4 2020 Cool high pressure was over the eastern Dakotas and Minnesota, with light and variable winds over much of central North Dakota. Some low stratus clouds had developed in the Jordan/Glendive Montana to Beach/Hettinger ND along a low level warm frontal boundary. Ahead of high pressure that was pushing in from the north, a cold front was crossing the forecast area. The high holds on with subsidence for tonight and a clear sky. Not as cold on Wednesday, actually quite a bit warmer with southwest winds and warmer air over us - aloft.
12Z data suggests an period of freezing rain/sleet before an eventual changeover to snow.
GOES-East clean IR imagery shows the upper level, positively tilted, longwave trough over the western US. In the low levels, brisk winds from the north-northeast have accentuated the chill today.
539 PM CST Tue Feb 4 2020 Mostly clear skies this afternoon thanks to a broad area of high pressure over the region, with a few clouds and perhaps some isolated flurries possible across Iron county this evening.
High pressure to our east and extending towards the Gulf tonight, will keep quiet weather conditions overnight.
Temperatures have warmed into the lower 70s most locations as the area of rains has continued to increase in size over southeast Texas and southern Louisiana. The cold front extends from a low in southwest Arkansas down towards Austin and finally over towards Rocksprings north of Del Rio.
1000 PM EST Tue Feb 4 2020 Deep mean-layer ridging persists across the Western Caribbean. Temperatures are in the lower to mid 70s with dewpoints in the upper 60s. Skies are mostly clear, although alto layers are spreading north from Cuba, and high-level cirrus is spreading northeast along the fringes of the mean-layer ridging.
The persistent feature will be a strong ridge centered near 40 north 140 west in the Pacific Ocean. A number of weather systems will develop and move around this high pressure area. In the short term, a moist northwest steering flow around the ridge will impact our area along with warmer marine air and rising snow levels.
546 PM CST Tue Feb 4 2020 /00Z TAFS/ A mix of wintry precipitation, including snow, freezing rain, and ice pellets will begin by 06Z tonight. An upper level trough currently across the Southwest United States will approach the forecast area overnight. Farther south across the Concho Valley, northern Heartland and Northern Edwards Plateau, expect the precipitation to changeover from rain to freezing rain/sleet mainly after midnight due to a low level warm layer on top of shallow sub freezing surface air. Significant travel impacts are possible, especially across the Concho Valley due to icy roads, especially bridges and overpasses.
438 PM MST Tue Feb 4 2020 Latest upper level analysis has positively tilted trof sliding through the Northern Plains and Central Rockies this afternoon with ridging across the western CONUS. At the surface, high pressure is located across the eastern Dakotas and across the Northern Rockies, with a weak lee trof in between. Temperatures across the area at 2pm are in the teens and 20s in snow covered areas, and in the lower 30s across northwest South Dakota. Steep lapse rates along the upper trof axis are producing the light snow showers currently. As diurnal heating wanes and trof shifts east, snow showers will slowly dissipate by late afternoon or early evening. Upper ridging will move in overnight with mostly clear skies expected and chilly temperatures.
753 PM EST Tue Feb 4 2020 Benign weather conditions remain across South Florida with high pressure dominating the weather pattern. As the gradient flow between the approaching front and departing high pressure builds on Wednesday, wind speeds will be stronger and some coastal areas could see some wind gusts on Wednesday afternoon in the 20 kt range.
An upper level trough currently over the Rockies will shift eastward today bringing some chances of light snow to the southern CWA. Wednesday: The upper level trough will be overhead on Wednesday. Temperatures on Wednesday will remain below average and will remain near or below freezing across the area.
Any brief change over (light freezing rain or sleet) from say Marble Hill, MO to Mount Vernon, IL late tonight will be of little consequence, if it happens at all. To our west, an upper level H5 trough will move east across the nation's mid section. On the back of the system Wednesday into Wednesday night, cannot rule out a period of light freezing rain or sleet, or even trace drizzle/freezing drizzle from SEMO into southern IL. It will likely be somewhat breezy Wednesday into Wednesday night as well, as the low deepens to our south and east.
This wind increase may take until midnight or later to reach some areas across northwest Minnesota, so temperatures should be cooler there. However, even with warmer temperatures, the wind will keep a chill in the air.
Clouds are expected to clear out across there after midnight and winds are expected to remain light so there should be some radiational cooling, dropping temperatures quickly into the single digits with the cooler airmass and lack of clouds. There is a little concern the temperatures could be cooler across southwest and north central Nebraska.
Models have trended warmer just above the surface, which will mean a higher probability of sleet occurring, especially across parts of south central into central Oklahoma. Some freezing rain may also occur, mainly southeast Oklahoma and some light accumulations appear possible.
215 PM MST Tue Feb 4 2020 Latest upper level analysis has positively tilted trof sliding through the Northern Plains and Central Rockies this afternoon with ridging across the western CONUS. At the surface, high pressure is located across the eastern Dakotas and across the Northern Rockies, with a weak lee trof in between. Temperatures across the area at 2pm are in the teens and 20s in snow covered areas, and in the lower 30s across northwest South Dakota. Steep lapse rates along the upper trof axis are producing the light snow showers currently. As diurnal heating wanes and trof shifts east, snow showers will slowly dissipate by late afternoon or early evening. Upper ridging will move in overnight with mostly clear skies expected and chilly temperatures.
643 PM EST Tue Feb 4 2020 Moisture will slowly increase across the area as a low pressure system approaches from the Lower Mississippi Valley the next few days.
An upper level trough currently across the Southwest United States will approach the forecast area overnight. Farther south across the Concho Valley, northern Heartland and Northern Edwards Plateau, expect the precipitation to changeover from rain to freezing rain/sleet mainly after midnight due to a low level warm layer on top of shallow sub freezing surface air. Significant travel impacts are possible, especially across the Concho Valley due to icy roads, especially bridges and overpasses.
Pressure falls are maximized over northeastern Montana along and ahead of a warm front which will shift into central North Dakota 12z-15z Wednesday. Cool high pressure over the eastern Dakotas/Minnesota this afternoon is forecast to drift southeast towards Iowa tonight, with developing low pressure in the Lee of the Canadian Rockies. This will result in a light southwesterly surface flow of 5 to 10 mph across western and central North Dakota, keeping the lower atmosphere mixed.
Mid-levels remain saturated, however, there has been considerable dryness in the low levels which has inhibited snowfall across the region. An upper trough will move through the area Wednesday with northwest flow setting up over the region late in the afternoon. A 500 mb trough axis crosses the Tri-State area Wednesday night.
436 PM EST Tue Feb 4 2020 Rain showers continue to stream across eastern Kentucky from the southwest as rich moisture transport takes place ahead of an approaching cool front and upper trough, stretching from the northern Great Plains to the Desert Southwest.
GAH AFTERNOON DISCUSSION: A departing mid-level trough will give way to NW flow through the remainder of this week. However, a few weak short wave troughs moving through the region could still bring some snow showers to Northeast Montana.
Cold front is on the doorstep of our CWA and will be moving into the region bringing much cooler temperatures to most areas overnight. Wed night: Will remain on the lookout for a narrow band of precip possibly developing to our west (or overhead) with the approaching upper trof axis. These conditions will be improving with the pas- sage of a cold front late tonight/early Weds morning. A weak cold front is still in the fore- cast for late Sat.
/issued 353 PM CST Tue Feb 4 2020/ Surface analysis shows a cold front extending across west Texas to the Missouri Bootheel. However, a strong to perhaps an isolated severe thunderstorm may be possible tonight across East Arkansas south of I-40 and into North Mississippi, but overall confidence remains low at this time due to the less than ideal instability and timing of the upper-level support with the cold front. By Wednesday, as an upper-level trough pushes toward the region, the severe weather potential will increase. Temperatures Wednesday will range from the lower 70s in our southern areas to lower 40s in far northeast Arkansas.
330 PM CST Tue Feb 4 2020 Mostly clear skies this afternoon thanks to a broad area of high pressure over the region, with a few clouds and perhaps some isolated flurries possible across Iron county this evening.
AMDAR soundings show a below freezing profile all the way up from KLBB north and west though a thin unfrozen layer is indicated around 8500MSL to the ESE of KLBB, conditions are expected to worsen toward midnight local as another batch of wintry precipitation overspreads the area. Surface temps from the West Texas Mesonet show the entire area is just at or below the freezing mark so any liquid that does fall out of the sky is expected to be snow from this point forward. Our stronger round of more widespread precipitaion will begin to take hold this evening through tomorrow midday as embedded disturbances round the base of the upper level trough and move across the CWA.
Upper trough over the desert southwest to continue deepening. Mid/Upr troughs draw further east, helping to spin up fairly good SFC/LL low. This low rides up frontal boundary on Wed, eventually crossing right over the mid- state Wed evening. As SFC wave moves north and drags our front east Wed night, heavy rain is expected to vacate by early Thu morning, although it will take into Fri morning for the upper trough axis to pass. Southerly winds will become more westerly/northwesterly as a weak cold front moves into the mid state this evening/overnight.