Aikyam-Lab/Synoptic-Bench huggingface dataset:
Primary question this period is maximum temp extent underneath tremendous upper ridge blowing up ewd of deep trough carving out through the wrn US and stormy wrn Atlantic through wrn Caribbean. Ridging sfc and aloft builds further to begin this period. Mid and high level clouds will spread over terminals but building ridge expected to inhibit eastward progression of decaying pcpn.
GAH PREVIOUS SHORT TERM DISCUSSION: An upper low is centered over western Canada today but is elongating from west to east. But the southwest portion of the upper low drops into the central Rockies Thursday that concentrates dynamics and moisture. A deepening upper trough across the western U. will maintain cooler than average temperatures and occasional precipitation chances. Directly behind it a large trough stretches from central California through Idaho, Alberta, and northern Saskatchewan. Behind that a large ridge resides over the Gulf of Alaska. The coldest air of the northern hemisphere sets over the Arctic Ocean just north of the Alaskan North Slope with modified arctic air making incursions into the trough over the Northwest territories.
1146 PM CDT Wed Sep 20 2017 High level moisture moving northeast around the Upper low in western Saskatchewan will spread into NE ND during the night. Surface ridging will shift east setting up return flow along with respectable warm advection overnight. Broad upper troughing deepens from the northern Rockies into northern CA putting fa back into sw flow aloft. Will be breezy and with thermal ridge axis shifting over the fa temperatures will recover above average with southern area into the valley close to 80.
the low level jet is expected to increase into the 25-35KT range along with an ongoing instability axis along and just east of the frontal boundary.
610 PM CDT Wed Sep 20 2017 Monitoring the cold front as it shifts east this afternoon and evening. The cold front will only make it south to about Interstate 80 tonight before the model consensus beings it north again as a warm front as ridge builds. The low-level moisture transport convergence continues to migrate north through the evening Thursday, into nrn WI and nrn MN.
953 PM EDT Wed Sep 20 2017 A ridge of high pressure at the surface and aloft will bring warm weather to Pennsylvania through the weekend. Ridge holding strong again Thursday and Thursday night.
This high-energy air is supporting a moderately unstable atmosphere with little convective inhibition per data from the Key West evening radiosonde balloon. Winds gusted to hurricane force in the lower Florida Keys, with a storm surge of 3-5 feet.
536 PM MDT Wed Sep 20 2017 Warm and dry pattern will be in place through much of the short term as a deep upper trough digs across the Great Basin, and increasing southwest flow aloft ahead of it over the CWA.
Low pressure will ride along the front and expect a wet period either side of frontal boundary.
803 PM EDT Wed Sep 20 2017 High pressure at the surface and aloft will remain parked over the region through the next several days, providing dry conditions and above normal temperatures.
1044 PM MDT Wed Sep 20 2017 The strong and broad Pacific trough continues to dominate much of the western CONUS today with the tight wind gradient persisting aloft under a +110kt upper level jet. The forecast remains on track over the next several days as the Pacific trough is expected to elongate and dig further south.
516 PM MDT Wed Sep 20 2017 19z surface analysis had cold front from MN to KS with high pressure over the central plains behind it. Developing lee trough over the Rockies combined with high producing gusty west/southwest winds over much of the CWA this afternoon. Moisture looks scant, so mid/high clouds will be main effect along with the usual Black Hills/foothills downslope warming and gusty winds over the higher terrain of the Black Hills and over the southern SD plains. Dry boundary layer will preclude pops, although a few showers may develop off the Big Horns late and approach the CWA as a cold front starts to sink southeast toward CWA.
930 PM PDT Wed Sep 20 2017 At 9 PM PDT, water vapor satellite showed a deep upper-level trough across the PAC NW.
945 PM EDT Wed Sep 20 2017 A mid to upper level trough will drift across the Carolinas through Thu, then linger while weakening through the end of the week. A vorticity disturbance will drift slowly eastward across eastern NC on Thursday, and will eventually feed into the broad upper trough extending SW from TC Jose off of the southern New England Coast. H8 temps and low-level thickness drop off ever so slightly, so perhaps a degree or two cooler when compared to today, but still in the same ballpark with afternoon highs in the 85-90 degree range.
1155 PM CDT Wed Sep 20 2017 Cold front at 18z had pushed just south of the area, and was defined very well by a wind shift and an associated cloud street field from northeast KS through northeast IA. The stalled front then begins to lift back as a warm front by daybreak Thursday. Quite warm and muggy conditions persist Thursday night with lows only in the lower to mid 70s.
612 PM CDT Wed Sep 20 2017 The large scale pattern tonight and Thursday shows a positively tilted flow, with upper riding extending from Texas northeastward into the eastern Great Lakes, and an upper trough moving into California and the Alberta/Saskatchewan border. As high pressure shifts off to the east and shifts our low level winds around to an easterly and southeasterly direction, the models develop the stratus near 900mb and usher that moisture first into Sioux City toward day break Thursday, then expand it north to northwestward deeper into our forecast area. The low level jet becomes quite strong on Thursday coupled with a tightening surface pressure gradient. Therefore south to southeast winds will become quite brisk helping to mix the lower atmosphere through about 1 km, where winds of 35 knots reside.
Surface ridging will shift east setting up return flow along with respectable warm advection overnight. Broad upper troughing deepens from the northern Rockies into northern CA putting fa back into sw flow aloft. Will be breezy and with thermal ridge axis shifting over the fa temperatures will recover above average with southern area into the valley close to 80.
812 PM EDT Wed Sep 20 2017 Limited moisture and broad ridging kept storm coverage isolated this afternoon, but a band of showers and storms is continuing to linger along the sea breeze south of Tampa Bay along and east of Interstate 75. High pressure will continue to ridge into the northeastern Gulf of Mexico through the end of week, with light winds and seas. The pressure gradient will increase this weekend as the ridge lifts north, bringing winds up to around 15 knots and seas of up to 3 feet offshore.
1007 PM EDT Wed Sep 20 2017 A ridge of high pressure at the surface and aloft will bring warm weather to Pennsylvania through the weekend. Ridge holding strong again Thursday and Thursday night.
834 PM EDT Wed Sep 20 2017 A mid to upper level trough will drift across the Carolinas through Thu, then linger while weakening through the end of the week. A vorticity disturbance will drift slowly eastward across eastern NC on Thursday, and will eventually feed into the broad upper trough extending SW from TC Jose off of the southern New England Coast. H8 temps and low-level thickness drop off ever so slightly, so perhaps a degree or two cooler when compared to today, but still in the same ballpark with afternoon highs in the 85-90 degree range.
The lower levels were quite moist with a layer of drier air observed between 700 and 500 mb.
An upper level low will maintain a chance of showers and cooler temperatures over Western Washington Thursday.
Convection developed near troughing to the nw today and has advected into interior se Ga.
1046 PM EDT Wed Sep 20 2017 High pressure at the surface and aloft will remain parked over the region through the next several days, providing dry conditions and above normal temperatures.
549 PM MDT Wed Sep 20 2017 The strong and broad Pacific trough continues to dominate much of the western CONUS today with the tight wind gradient persisting aloft under a +110kt upper level jet. The forecast remains on track over the next several days as the Pacific trough is expected to elongate and dig further south.
Chattanooga Airport, TN 66 88 65 87 / 10 20 10 10 Knoxville McGhee Tyson Airport, TN 65 86 64 86 / 10 20 10 10 Oak Ridge, TN 65 86 65 87 / 10 20 10 0 Tri Cities Airport, TN 59 85 60 85 / 10 30 10 10.
Weak high pressure is over the Eastern U. Expect mostly cloudy skies with light winds and lows in the lower 70s.
Warm and dry pattern will be in place through much of the short term as a deep upper trough digs across the Great Basin, and increasing southwest flow aloft ahead of it over the CWA.
943 PM EDT Wed Sep 20 2017 High pressure will prevail through this weekend. The high will weaken and shift inland as Hurricane Maria tracks northward off the Southeast U.
638 PM CDT Wed Sep 20 2017 Cold front at 18z had pushed just south of the area, and was defined very well by a wind shift and an associated cloud street field from northeast KS through northeast IA. The stalled front then begins to lift back as a warm front by daybreak Thursday. Quite warm and muggy conditions persist Thursday night with lows only in the lower to mid 70s.
825 PM MDT Wed Sep 20 2017 Broad/deep upper level low/trough with center over the Canadian Prairies continues to elongate to the SW this evening as upper level energy drops south into northern CA, maintaining a fast and cold SW flow aloft across the Northern Rockies and MT. Snow levels currently range from around 5500 ft across northern areas to around 7500 along the ID/WY border this evening, with only minor lowering anticipated through tonight, keeping bulk of heavier precipitation across far SW MT in the form of rain or rain snow mix at pass levels through tonight with accumulating snowfall limited to the higher peaks.
A region of low pressure will overspread the Western states the latter half of this week.
1028 PM CDT Wed Sep 20 2017 The large scale pattern tonight and Thursday shows a positively tilted flow, with upper riding extending from Texas northeastward into the eastern Great Lakes, and an upper trough moving into California and the Alberta/Saskatchewan border. As high pressure shifts off to the east and shifts our low level winds around to an easterly and southeasterly direction, the models develop the stratus near 900mb and usher that moisture first into Sioux City toward day break Thursday, then expand it north to northwestward deeper into our forecast area. The low level jet becomes quite strong on Thursday coupled with a tightening surface pressure gradient. Therefore south to southeast winds will become quite brisk helping to mix the lower atmosphere through about 1 km, where winds of 35 knots reside.
1132 PM CDT Wed Sep 20 2017 Monitoring the cold front as it shifts east this afternoon and evening. The cold front will only make it south to about Interstate 80 tonight before the model consensus beings it north again as a warm front as ridge builds. The low-level moisture transport convergence continues to migrate north through the evening Thursday, into nrn WI and nrn MN.
Otherwise a warm night for the near Autumn season, with 9 PM temperatures in the lower 70s.
/issued 148 PM CDT Mon Mar 26 2018/ Upper trough coming in from the west will slowly progress east the next couple of days.
1153 AM MDT Mon Mar 26 2018 Upper level trough over the Great Basin showing signs of splitting in latest water vapor imagery with weak circulation developing over east-central Nevada. Focus remains north of Interstate 70 as we could see a few inches of new snow across the Eastern Uinta Mountains and over the Park and Gore ranges later today as the trough advances through the region. Could see several inches of new snow pile up over the highest peaks of the San Juans, but significant impacts at Pass level are not anticipated and snowfall amounts are expected to taper down rather quickly as we work below 11k.
/issued 1107 AM CDT Mon Mar 26 2018/ Minor changes to the current forecast which was to raise the high temperature for the afternoon for areas along and to the South of Interstate 20 which may not affect the wording in the zones.
353 PM EDT Mon Mar 26 2018 High pressure will control our weather through Tuesday morning. High pressure will keep fair weather over the region through Tuesday afternoon, before a frontal system sliding into the Great Lakes brings increasing clouds and rain showers to the region. The atmosphere will decouple tonight, allowing temperatures to drop into the lower-20s, even as warm air advection begins aloft. High pressure is in firm control this morning, with clear skies fixed across NY and PA.
As a warm front approaches from the west clouds will thicken back up tonight and there will be a chance for showers. A better chance of showers will occur Tuesday night as low pressure moves from the mid MS valley into the OH valley and a cold front approaches the area. A southern stream disturbance near the White Sands of southern New Mexico will combine with multiple rounds of northern stream energy, stemming from an upper low across the western shore of Hudson Bay.
In kind, tomorrow's highs should climb into the upper 60s to around 70 and with an outside chance that the sun breaks out, we might even end up warmer than that. Models continue to show a slow moving cold front developing to our west tomorrow afternoon and around midnight, have it breaking into our far northwest counties.
342 PM MDT Mon Mar 26 2018 An upper low over Arizona will move over New Mexico Tuesday afternoon and evening, keeping clouds around.
555 PM EDT Mon Mar 26 2018 Periodic rain chances return Tuesday through the rest of the work week with a series of crossing areas of low pressure. There still is a low chance of a brief period of light freezing rain for areas N of Route 422 and in the higher terrain, though increasing cloud cover should limit the temperature decreases. The best chance for freezing rain is expected in Garrett and ern Tucker counties where SE upslope flow should keep temperatures closer to freezing, though full sun today has resulted in pavement temps in the 50s and 60s, so expected impacts would be minimal. The first such break should come Tuesday evening/night in the wake of the lifting warm front.
Currently expect warm air advection to continue to be strong enough across the region to keep temperatures above freezing through the lowest levels. As this system begins to exit Monday evening, did include a small amount of ice accumulation as temperatures fall close to freezing and mid-level moisture peels out, but impacts should be minimal as road surfaces are forecast to remain above freezing. Fog will be possible as well, especially with dewpoints just above freezing across the snowpack in northern Wisconsin. Models are generally all over the map with the details, ranging from more of a flattened troughing scenario as depicted by the gfs/gfs ensemble mean, to the more amplified scenarios develop by the ecmwf/canadian models.
128 PM EDT Mon Mar 26 2018 Aviation Winds will become southerly in advance of a cold front today and tonight. The south winds will bring in slightly warmer air and rain.
Conceptually, would expect this location to be at the nose of the low-level jet, which is where isentropic ascent will be maximized. The 26/12Z NAM and GFS suggest the nose of the low-level jet will be somewhere near I-44 tonight.
359 PM EDT Mon Mar 26 2018 An upper closed low sits over Arizona with an upper ridge axis running from western New York down through Cincinnati, Ohio. At the surface the low is west over northeastern New Mexico and the high is just north of Maine. Expect lows in the mid to upper 50s with winds from the south at 10- 15 mph and gusts in the low 20s.
This will bring high temperatures into the low 60s for most of the mid state, along with winds around 10 to 15 mph gusting to around 20 mph at times, especially along the I-65 corridor. Winds look to stay up overnight as well, so low temperatures should not fall too much, and most of the area will see lows in the low 50s.
Across the west, clouds increase across the west and central, and there's still an outside chance at some light shower activity reaching into my western zones before sunrise, which would produce patchy freezing rain if it did so. Confidence still too low on this, and think most areas warm above freezing before precip arrives. Have placed the highest POPs of 80-90 pct across the northwest counties for the afternoon hours, where low level jet focuses best moisture and lift. Cold air damming and increasing clouds/moisture will keep temps slightly cooler than guidance, with most areas ranging from the upper 30s north to the lower 40s south.
201 PM MST Mon Mar 26 2018 A low pressure system will move through the region early this week bringing slightly below normal temperatures through Tuesday and breezy to windy conditions.
Snow and occasional light freezing precipitation continues across the northern and eastern parts of the area. Most of the area is seeing readings right around the freezing mark and we have had drizzle/ice/fog for a good part of the CWA, while rain/ice/snow is moving in from the west/southwest and we also see freezing rain/snow showers over the southern Coteau. Temperatures today will struggle to warm with the stratus in place, and while most should get just above freezing, this is not universal, with the Coteau the main area of focus though this is not exclusive. The split positive tilt mid level trof across the central and western CONUS at the beginning of the period should consolidate into a full latitude trof across the central CONUS during the period.
614 PM EDT Mon Mar 26 2018 High pressure will crest over the area through Tuesday.
Warmer air aloft and ridging in the mid to upper levels has kept things dry acrs the northwest Gulf Coast, with the nearest convection per regional radar mosaic occurring well northwest of the area. Ridging aloft will weaken as a trough over the western CONUS continues to dig and cutoff as it moves east acrs AZ, allowing southwesterly flow to become further established over the area. The upper trough/low will very slowly move east through the next few days.
A weak frontal boundary is washing out over the FL peninsula as strong high pressure along the eastern seaboard veers the local winds out of the east.
256 PM CDT Mon Mar 26 2018 Satellite loops showing a good plume of moisture coming into the southern Rockies and central plains at 19Z, around the base of the western trough moving across southern California. At the surface, low pressure was located over south central Kansas with an inverted trough extending into southeastern Nebraska and a warm front into central Missouri. A few showers will continue this evening mainly east of the inverted trough over southwest Iowa. Models have the front pushing south towards Oklahoma this evening as the low lifts northeast into north central Missouri and a northern stream trough advances into the northern plains.
An upper ridge starting the day over the Mississippi River has moved east, stretching north along the west side of the Appalachians. As the forecast moves into tonight, a strong upper system over the desert Southwest moves east along the US/Mexico border, pushing the upper ridge farther east. After a bit of discussion with neighboring offices, it is felt that leaning towards the warmer side of the solutions is warranted, with subsidence from the upper ridge the main driver. For tonight's lows, will have a smaller gradient than last night, but due to the upper ridge, above seasonal are expected. For Tuesday, highs closer to seasonal are expected with mostly cloudy skies limiting any daytime heating balancing subsidence from the upper ridge.
306 PM EDT Mon Mar 26 2018 This morning's regional RAOBs sampled rising heights at all mandatory levels, highlighting the amplifying ridge complex centered to our west, and the intensifying anticyclone to our north.
Short term models continue to indicate strong lift ahead of incoming trough channeled over central MN into the northeast through about 00z. We are near critical level with boundary layer temperatures around freezing just to the northwest of the metro. The higher totals should lift along and north of I94 and over Morrison and Mille Lacs Co.
A low pressure system will move across Arizona through Tuesday, bringing colder weather and a good chance for rain and snow showers. Showers are filling in this afternoon, primarily across Coconino and northern Yavapai counties, in response to an upper level low moving into western Arizona. This low will gradually meander through the state overnight, continuing to bring scattered showers to areas generally from Prescott to Window Rock northward. As the low moves east overnight, winds will shift to northerly and become breezy by Tuesday morning. The low will shift eastward on Tuesday, bringing similar conditions that we are seeing today to portions of Navajo and Apache counties.
Developing low pressure across the central plains will continue to push to the northeast, with its warm front extending into southern Wisconsin. There is currently scattered precip along the warm front in eastern Iowa, and this precip will reach southern Wisconsin later this afternoon. In addition to the warm front, and mid level short wave will push into the region this evening. The combination of the wave, low level forcing associated with the low, and ample moisture currently streaming in, will result in widespread precipitation in southern Wisconsin tonight. In addition, there is a chance that some patchy fog develops in the early morning hours when the winds die down as the low moves across the region.
A cold front currently stretched across far northwest Oklahoma will begin pushing southward across after 06Z, resulting in a north surface wind shift across our terminals as the morning progresses. Another, stronger short- wave trough will bring a chance for severe thunderstorms to part of southern and central Oklahoma late this afternoon and evening. South central and southeastern Oklahoma are expected to be under the influence of another wave emanating from the upper low over the southwestern U.
146 PM MST Mon Mar 26 2018 A low pressure system will move through the region early this week bringing slightly below normal temperatures through Tuesday and breezy to windy conditions.
The rest of the area will linger in the 40s through this evening as the lower clouds stay in place. Winds will continue out of the north through tonight, allowing these improvements to cloud and visibility conditions in wake of a cold front that pushed through earlier this morning. Another weak cold frontal boundary will push through overnight, bringing a more easterly component to the northerly winds, allowing for upslope effect. The models are all different in handling this low level situation but all tend to push the upper level trough out of the area to the east fairly quickly tomorrow. As the upper trough axis approaches, there will be chances for light rain showers later tonight and into Tuesday.
219 PM EDT Mon Mar 26 2018 Warm front tonight into Tuesday.
Much warmer air building into western areas with highs in the 50s expected along and west of the James/lower Missouri River Valleys.
Generally quiet weather, with warmer than recent temperatures, is on tap for the week. The forecast area will remain just to the east of an upper ridge axis, and above normal temperatures are expected for most of the week. A warm front will bring a chance for rain mainly to the coast north of Cape Blanco and the Umpqua Basin today through tomorrow.
As a warm front approaches from the west clouds will thicken back up tonight and there will be a chance for showers. A better chance of showers will occur Tuesday night as low pressure moves from the mid MS valley into the OH valley and a cold front approaches the area. A broad trough will gradually move from the Mississippi Valley to the Eastern Seaboard.