Aikyam-Lab/Synoptic-Bench huggingface dataset:
This will glacially spin off to east, allowing ridging to gradually build in. Temperatures, and probably even sun angle, have really affected accumulations here, but at least 1-6 additional inches are possible in the higher terrain with a trace elsewhere along the South Shore. Snow should wind down tomorrow, though this area will stay on the cooler side, closer to that cut- off low. Further into the week, we really start to see some (relative to the last two weeks) warmer temperatures with ridging and high pressure. Closer to Lake Superior, a weak lake breeze may develop, keeping lakeshore areas cooler in the 40s and 50s.
(Today through Wednesday) A large deep-layer trough will continue to oscillate over the Northeastern CONUS during the short term period while longwave ridging sits in place over the Central CONUS. Similarly, temperatures should drop sharply after dark with clear skies and decreasing winds, so utilized some of the cooler solutions to forecast lows ranging from the lower 40s north to upper 40s south.
(Today and tonight) Currently we have mid and upper level clouds streaming across the region as subtropical moisture rides up and over the ridge in the area. With southwest flow edging into the area from the west, a few late afternoon and evening thunderstorms are expected to develop over the higher terrain to our west.
(Today and tonight) An upper level omega block ridge remains in place across the center of CONUS, extending from the Montana Rockies to South Texas. Upstream from the ridge is a large closed low centered near San Francisco. Modest southeasterly flow in the low levels will result in some moisture advection, eventually leading to a moist, instability axis extending from northwest Texas northwestward to the South Plains with a dryline setting up vicinity of the New Mexico state line later this afternoon. Aloft a mid-level short wave trough is showing up pretty well on water vapor imagery moving northeastward across Chihuahua. This trough has helped generate some isolated convection on the Sierra Madre last evening, and it is this trough that will add some mid level support for thunderstorms that are expected to fire along or east of the dryline this afternoon.
145 AM MDT Tue May 2 2023 Current surface map places high pressure across the Dakotas. Upper ridge, part of Omega block, is located over the Northern Plains. Upper ridge weakens Wednesday as western CONUS trough slowly advances eastward. Slow eastward progression of upper trough continues for the end of the week into the weekend, resulting in daily chance of showers/thunderstorms.
1015 PM MDT Mon May 1 2023 Synoptic Overview: An omega block -- characterized by an upper level trough/low along the Pacific Coast, an upper level ridge over the Rockies and High Plains, and an expansive upper trough/low over the eastern CONUS (east of the MS River Valley) -- will prevail through the short term period. Today-Tonight: Synoptic subsidence on the eastern periphery of the aforementioned ridge / western periphery of the east CONUS trough. along the western periphery of a persistent low-level (surface to 850 mb) ridge extending NNW from the Lower MS River Valley/Gulf Coast to the Dakotas. with afternoon highs in the lower-mid 70s and overnight lows in the mid-upper 40s. Trough entrenched along the west coast will be slow to lift out due to a blocky upper pattern.
346 AM EDT Tue May 2 2023 Relentless high amplitude troughing ensures another 24 to 36 hours of cold and unsettled conditions prevail throughout Southeast Michigan. Governing closed low now featured over Ontario will briefly retrograde before ejecting southeast during this time, as another substantial lobe of vorticity pivoting cyclonically around the northwest flank of this system repositions and strengthens the height fall center. A marginal freezing level maintains the possibility for some inconsequential snow showers to mix in at times. Deep layer northerly flow still entrenched Wednesday as the lower height field begins the slow eastward release.
142 AM EDT Tue May 2 2023 Slow moving low pressure will bring chilly, windy and damp weather through Tuesday.
Tuesday will be breezy and slightly warmer with highs 70 to 80.
Discussion: The overall synoptic pattern remains tied to Omega blocking system keeping us in northwest flow for one more day before starting to break down. After another day of generally cool northwest flow, the blocking pattern will finally start to breakdown as the upper low over the Great Lakes region translates east.
Water vapor satellite imagery displayed a deep upper low across the Great Lakes region, with several waves circling around the low, a ridge stretching north from the Desert SW across the Rockies, and a low off the northern CA coast. At the surface, a 983 mb low was stacked below the upper low, a 1014 mb high was across south FL and a 1021 mb high was across the northern Plains.
407 AM EDT Tue May 2 2023 A stalled boundary is in place across north FL this morning with weak ridging across the local area. Weak ridging and dry conditions continue through the week as flow gradually turns to the N/NW through mid week and then to the E/SE with afternoon sea breezes for the end of the week.
1206 AM EDT Tue May 2 2023 A broad trough will prevail across the area into mid week.
Strong wind gusts would be the main threat, especially in the lower elevations given the decent dew point depressions, approaching 50 degrees in some locations. Southerly flow will keep temperatures warm as well with highs in the 70s and 80s fairly widespread East of the Divide in the lower elevations. However, coverage should be less as heights are higher and with the ridge building back northward, instability parameters are not as impressive as today.
Upper level northwest flow on the back of a fairly deep trough is bringing pleasant feeling warm and dry air with light generally northerly winds. By Wednesday ridging now to our west will move over the area signaling a warming trend through the end of the week.
1225 AM CDT Tue May 2 2023 (Tonight through Tuesday night) Upper level ridge along the Rio Grande into the southern Rockies will move eastward to an axis from the southern high plains down to deep south Texas Tuesday and Tuesday night. The low level flow will be weaker for Tuesday night but low clouds will remain over the region.
Therefore, synoptically, an omega blocking pattern exists. With northwesterly flow present, CAA will be taking place keeping the area rather cool again today but the highest elevations of the CWA could see a rain/snow mix before the eastern low pressure center ejects out of the region overnight tonight. Lastly with the trough moving through and high pressure building across the Central Plains; increased surface winds will be present today. The large scale pattern in the extended will start off with a large trough of low pressure aloft moving through central New England on its way to sea.
(Today) Low pressure system centered over the Great Lakes region is expected to remain in place for one more day.
1234 AM CDT Tue May 2 2023 (This evening through Wednesday) A robust sfc center of low pressure in the neighborhood of 980mb remains anchored across southern Quebec in Canada with an evident tightening of isobars extending well away from the center of the low pressure to as far as Arkansas which has provided gusty afternoon winds over most of the state. Temperatures will remain on a slow warming trend overall as the upper lvl omega block slides eastward and Arkansas encounters stout upper lvl ridging. Expect weather conditions to remain distinctly similar each day through Wednesday with high temperatures in the 70's across most of the state and morning low temperatures in the low 40's to mid 50's statewide as well.
Key Messages: - Temperatures start today around freezing in northeast Nebraska, with a freeze warning in effect until 8 AM. Wednesday will be one more dry, sunny day with very high fire danger, but high pressure over the Northern Plains finally starts to break down with the destruction of the Omega Block pattern aloft which has held us in this pattern for the last several days. With the shifting of the trough out west eastward, southerly flow pushes northeast across all of Nebraska and into western Iowa on Wednesday afternoon, which will bring afternoon temperatures up into the low-to-mid 70s.
A low pressure system off the coast of California will bring gusty southwesterly winds to the region through much of the week.
There is some uncertainty in the western extent of cloud coverage today, but with the amount of dry air shown in RAP/HRRR soundings it will not take much for relative humidity values to plummet into the low 20s this afternoon. TONIGHT: FROST POTENTIAL High pressure builds in from the west tonight resulting in clear skies and uninhibited radiational cooling. LOOKING AHEAD: TEMPERATURES RISE, RAIN RETURNS TO THE FORECAST Ridging across the central CONUS amplifies mid-week into the weekend ushering in a period of warmer weather with periodic precipitation chances.
A stubborn upper low along the CA coastline has finally gotten close enough to transition mid level flow to the southwest over the region.
This corridor of dry air lies between a nearly stationary upper-level low spinning over the Great Lakes and amplified midlevel to upper-level ridging extending from Mexico northwestward through the Great Basin and into the Pacific Northwest. West of the ridge, another upper-level low is spinning near the West Coast, completing an omega blocking pattern. Latest sfc analysis shows a ridge extending from Manitoba and Saskatchewan southward through the southern Plains. Aforementioned deep ridging and upper lows will slowly slide eastward over the next 36 hours.
The urban corridor and plains trend near upper 30s to low 40s tonight; the mountains and foothills trend near the low 30s to low 40s. 40 inches mainly in the higher terrain. Wednesday the ridge axis will be over northeastern Colorado which will bring warm temperatures to the area and perhaps the warmest day of the week. The ridge begins to shift east Wednesday evening which will break down the omega blocking pattern that has been all the hype as of lately.
135 AM EDT Tue May 2 2023 Dry, breezy, and unseasonably cool weather will prevail through Wednesday as Canadian high pressure builds toward the East Coast. Warmer weather will develop late in the week as the high moves offshore. A deeply occluded and nearly stationary area of low pressure in the Great Lakes will be our main weather-maker through the period. A broad and moderately strong swath of northwesterly winds will flow cyclonically around the low into the Carolinas.
/20/ (This evening through Wednesday Night) Upper-air pattern tonight will somewhat resemble an Omega Block of sorts, with a large area of low pressure just off the northern coast of California, while another large area of low pressure centered over the Great Lakes. At the same time, high pressure aloft stretches from Mexico northward into Montana.
Several troughs continue to rotate into the area tonight with the latest tossing a patch of clouds as far west as US71, just entering our Iowa border counties at 0630z. The net effect will be to keep mins over the northeast/east a bit warmer through morning.
120 AM PDT Tue May 2 2023 Cooler than average temepratures for the Valley with a warmup to the mid to upper 70s expected over the weekend.
The HREF MinRH seems to perform well in these dry, deep mixing days, so have decreased the humidity values to the low end of the blended guidance.
(Today and tonight) Dry conditions are expected during the day today as the Southern Plains remains within a ridge axis between two upper-level closed- lows across the western and eastern U. Ascent associated with feature will result in widespread convection across the High Plains, which will move to the east-northeast.
(Today through Wednesday) Upper air analysis this morning shows a ridge axis over Texas with the flow turning from northwesterly over the east to southwesterly over the west. The low level flow will become more southeasterly today and push the front northward as a warm front. With a cloudy start to the day, temperatures today will be a little cooler than yesterday.
1152 PM CDT Mon May 1 2023 (This evening through Wednesday night) Warm, dry weather remains in place today with RH's dipping into the 30s and highs in the low 80s. Persistent eastern CONUS troughing will provide northwesterly upper flow and a steady stream of weak surface anticyclones that will keep winds light and variable through the period. Winds remained elevated enough last night that temperatures did not cool as efficiently and given highs are on the higher side of NBM guidance, a bit apprehensive to being more aggressive with cooler lows tonight so they're being kept as is. High temperatures will still reach the low to mid 80s regardless of the cloud cover.
Well defined area of low pressure aloft will continue to drop south, allowing mid level heights to begin rising overnight. The ridging build in through the mid levels will set the stage for a much warmer day on Tuesday with highs into the 70s in most areas. Upper level low off the Oregon coast late this evening and will move south and end up near KSFO Tuesday. Light flow in the lower levels.
Upper level ridge axis is centered across central MT this evening with mainly clear skies across most of the forecast area. At the surface, a fairly strong pressure gradient exists across the region between high pressure centered over the Dakotas and deepening low pressure across ID and the Northern Great Basin, resulting in gusty east winds through early this evening, especially in areas where terrain enhances easterly low level flow, including the Lewistown and Bozeman areas. By the end of the week, cooler temperatures will move back in, along with a chance for a more widespread rain and high elevation snow. The upper level ridge is over MT, resulting in fairly quiet weather conditions as of early this afternoon.
High pressure takes control over the region and temps will begin to rebound Wednesday onward following today's continued cold. On Wednesday the aforementioned high pressure moves in place over the region following the persistent low from the past several days.
Tonight, lows are expected to be in the lower 70s with light southeasterly winds.
(Today through Wednesday Night) Not much of a pattern change going on in the short term with a upper level ridge over Texas providing us with mostly clear skies. Really no chance of meaningful precipitation in the short-term period, though there is a non-zero chance of some streamer showers developing Wednesday afternoon west of the Brazos River as daytime heating combined with the low level moisture. Temperatures will be rising through midweek with highs this afternoon expected in the low 80s, then into the mid 80s on Wednesday. Overnight lows will be in the low to mid 60s.
138 AM EDT Tue May 2 2023 (Rest of today through Tuesday) Dry and benign weather will persist through early week over the southern Florida peninsula with the lack of any significant surface features and the establishment of the Omega Block synoptic upper level pattern across the CONUS (ridging over the central US while troughing flanks the ridge along the Pacific West Coast and across the Northeast).
Nevertheless, we have reached 35+ mph gusts the past two days, and forecast soundings supports mixing that may deepen a bit further today, possibly yielding gusts of ~40 mph, especially in the higher elevations. Forecast highs will reach the upper 60s to around 70 in valley areas, and a few degrees cooler atop the higher elevations.
234 AM CDT Tue May 2 2023 06z surface data has deep low pressure in the Ontario Province with a strong high over the northern Plains. These low RH values combined with the wind and somewhat warmer temperatures 'could' result in a stealth fire weather day. When the low RH values, near full sun, wind and temperatures are taken into account, all would aid in drying out vegetation (especially grasses). Tonight, quiet but chilly conditions will be seen has high pressure builds into the Midwest.
While the lowest levels below 900mb may remain dry the increase in moisture in the 700-500mb layer may have enough moisture and forcing to allow for some sprinkles to reach the surface. Unfortunately the upper low will keep the region fairly cool today though southwest could see temperatures get into the 50s with maybe some sun. By the evening clouds associated with the upper low will finally push out and bring us one more chilly night before we return to more normal conditions going forward. overnight lows should be expected to fall to near freezing with potential for some frost overnight if winds can calm enough.
Mostly clear skies, light winds and dewpoints in the lower 60s have allowed for excellent radiational cooling at interior locations of the larger islands overnight, with North Big Pine down to 62F and the office backyard here in midtown Key West down to 67F as of 4 AM. Temperatures along waterfront locations in the Keys are mostly in the lower to mid 70s. The gyre currently over the Great Lakes will drift slowly eastward across the Northeastern states during the next few days, keeping the subtropical ridge suppressed to our south, preventing any deep moisture return and maintaining an unusually dry airmass at the surface and aloft across our area.
Highs on Wednesday slightly warmer in the mid to upper 60s, with highs Cumberland Plateau Region remaining in the upper 50s to around 60 degree range.
(Today through Wednesday) A large closed low over the eastern Great Lakes Region will slowly drift southeast to a point just off the Northeast coast by Wednesday evening. Highs are forecast to reach the upper 80s to lower 90s, with overnight lows ranging from the upper 60s along the coasts to the lower 60s across the interior.
1108 PM MDT Mon May 1 2023 Key messages: 1) Increased shower/thunderstorm chances Tuesday Mainly isolated convection firing over the higher terrain this afternoon in response to slight increase in low level moisture/instability, though storm strength is still rather weak as surface CAPE is only a few hundred J/KG, and t/td spreads are rather large. On Tuesday, low level moisture continues to increase along and east of the mountains, while mid level wave works through the ridge and crosses srn Colorado in the afternoon. Wednesday still looks to be the warmest day of the period, as the ridge axis passes overhead. Highs into the upper 70s and low 80s are likely for our plains, with warmest temperatures remaining concentrated to the lower Arkansas River Valley.
Therefore, synoptically, an omega blocking pattern exists. With northwesterly flow present, CAA will be taking place keeping the area rather cool again today but the highest elevations of the CWA could see a rain/snow mix before the eastern low pressure center ejects out of the region overnight tonight. Lastly with the trough moving through and high pressure building across the Central Plains; increased surface winds will be present today.
554 AM CDT Tue May 2 2023 (Today through Wednesday) A large deep-layer trough will continue to oscillate over the Northeastern CONUS during the short term period while longwave ridging sits in place over the Central CONUS. Similarly, temperatures should drop sharply after dark with clear skies and decreasing winds, so utilized some of the cooler solutions to forecast lows ranging from the lower 40s north to upper 40s south.
Showers and storms should return to the area later this week and last through the weekend as a warm front moves north.
Two-three significant short wave disturbances are poised to round the southern periphery of the parent low and across the lower Ohio Valley and Tennessee Valley over the next 24-36 hours. Therefore, synoptically, an omega blocking pattern exists. With northwesterly flow present, CAA will be taking place keeping the area rather cool again today but the highest elevations of the CWA could see a rain/snow mix before the eastern low pressure center ejects out of the region overnight tonight. Lastly with the trough moving through and high pressure building across the Central Plains; increased surface winds will be present today.
A stalled boundary is in place across north FL this morning with weak ridging across the local area. Weak ridging and dry conditions continue through the week as flow gradually turns to the N/NW through mid week and then to the E/SE with afternoon sea breezes for the end of the week.
This east wind developed thanks to the thermal trough to our west and higher pressure east of the Divide. Besides the high confidence for breaking a few high temperature records at Kalispell, Missoula, Eureka, Libby, West Glacier, Pierce and Powell, another round of showers and thunderstorms is anticipated today.
The higher elevations will see some late-season accumulating snow. Cold closed upper low is centered near the Bay Area early this morning with scattered showers now covering most of interior NorCal. Some light snow is occurring over the high Sierra, but traffic cameras indicate wet road surfaces so far given the recent mild temperatures. The cool and unsettled weather will continue today into tonight with scattered showers as the low remains centered near the Bay Area. The low is forecast to drift further south the second half of the week with shower chances mainly retreating to the NorCal mountains.
610 AM CDT Tue May 2 2023 (Today through Wednesday Night) Not much of a pattern change going on in the short term with a upper level ridge over Texas providing us with mostly clear skies. Really no chance of meaningful precipitation in the short-term period, though there is a non-zero chance of some streamer showers developing Wednesday afternoon west of the Brazos River as daytime heating combined with the low level moisture. Temperatures will be rising through midweek with highs this afternoon expected in the low 80s, then into the mid 80s on Wednesday. Overnight lows will be in the low to mid 60s.
943 AM CDT Tue May 2 2023 Forecast continues to remain on track this morning as high pressure invades the Ark-La-Tex. Still anticipating highs this afternoon in the low 80s. Low-level southerly flow across the ArkLaTex will bring increased moisture as well as a warmer airmass to the region.
Strong high pressure ridge will result in continued anomalous warmth through midweek.
Aside from the river flooding, a few radar returns are showing up tonight as an upper level low remains situated to our south. By Wednesday, the upper level low appears to move farther south, although still close enough to impact the weather in the region. The most likely location for some thunder will be in the Cascades as the high resolution ensemble forecast system is predicting a fair amount of convection in the region.
(Tonight through Wednesday night) More quiet weather in the short term forecast with mid-level ridging remaining in place. We'll see increased cloud cover and in turn, cooler temperatures today. A pool of (at least compared to yesterday) substantially cooler 850MB temps is noted today and tomorrow at 13-15C. Expect a weak to moderate southeasterly flow today with a more easterly flow tomorrow while a weak coastal trough tries to develop. High temperatures both days range from the low 80s east to the upper 80s west.
627 AM CDT Tue May 2 2023 (Today and tonight) Dry conditions are expected during the day today as the Southern Plains remains within a ridge axis between two upper-level closed- lows across the western and eastern U. Ascent associated with feature will result in widespread convection across the High Plains, which will move to the east-northeast.