Aikyam-Lab/Synoptic-Bench huggingface dataset:
(This evening through Sunday) Northwest flow (aloft) has set up as upr ridge remains nearly stationary over the Lower Mississippi River Valley. A relatively quiet short-term period is expected across north and central GA, but that could change by late tomorrow (Sunday) and into early Monday as a series of upr lvl disturbances cut through the aforementioned ridge. Some of the higher-res models are hinting at remnants of an MCS originating somewhere between the Ohio and Tennessee River valleys to our north and west, could move across parts of the area Sunday night/early Monday morning. Temperatures will continue to be mild/warm given increased moisture and cloud-cover, along with influence from upr ridge (higher heights = warmer temps).
This upper low will slowly transition north thru today. This will keep chances for showers all day into tonight for northern 1/2 of the fcst area while southern 1/2 of the fcst area is on the south side of upper low and a bit drier airmass.
/ISSUED 546 PM MDT Sat May 6 2023/ Satellite imagery this afternoon shows one of several smaller scale circulation centers embedded with a larger scale/negatively tilted trough across the western US centered over Western portions of N- central MT.
Breezy surface winds from the southeast will help to make highs feel a little cooler in shady areas.
As an upper level ridge over the Mississippi River Valley flattens today and the mid level capping inversion erodes, showers and thunderstorm are expected to be in more abundance today than the past couple of days. At this time, our forecast delays the development of this additional activity until Monday night as a cold frontal boundary makes passage from north to south through the region.
Early this morning, the synoptic pattern was characterized by very broad troughing generally centered over the western CONUS, and weak ridging over the Ohio Valley region, with southwest flow over the Dakotas. Highs today will be in the lower 50s north central to the mid 60s southwest.
Convergence at the nose of low- level jet, and veering wind profile with the low level jet advecting in moisture are the driving force in an otherwise nebulous pattern beneath mean ridging.
(Today through Monday) The ridge remains in place today, so precipitation will be more like summertime activity with the pop up hit and miss variety through early evening.
It appears that the focus, if something were to develop, would be near and south of a Vermillion to Spencer IA line and if the higher probabilities for instability work out, it would likely be closer to a Sioux City to Storm Lake line. Right now the low levels do not appear overly favorable for any tornadic activity with weaker shear and somewhat dry conditions.
346 AM CDT Sun May 7 2023 Key Messages - Near record high temperatures are forecast once again this afternoon with readings in the lower 90s.
140 AM EDT Sun May 7 2023 High pressure will bring another day of dry and pleasant weather on Sunday. Much of the upcoming week looks dry with high pressure overhead. As of 140 AM EDT, high pressure remains overhead and will continue to do so through the overnight before beginning to push off to the east on Sunday. Upper-level ridging will continue to build into the region through the day Sunday. Expect a variation in low temperatures overnight with most locations falling into the 40s with some mid to upper 30s across the higher elevations. Confidence continues to increase on some rainfall that pops were increased into the high chance and likely categories with this latest update. Fair and seasonable Monday night with lows in the lower to mid 40s with 20s above mainly 1500 feet.
1237 AM CDT Sun May 7 2023 (This evening through Monday) An upper ridge is building over the eastern half of the U. with an upper trough over the western half of the country. The ridge will continue to build through Sunday. By Monday, the ridge will flatten somewhat in the east and build back to the west. A warm front has lifted north today and temperatures have warmed up considerably. Dew points are mainly in the lower to middle 70s.
high pressure. The east breeze will also push warmer temperatures to this side of the state.
This resulted in a modest lowering of Min T over the eastern zones where earlier convection left temperatures slightly cooler than anticipated. 24 (Tonight through Monday night) High pressure at the surface remains centered in the Atlantic near the Carolina Coast. Aloft, weak ridging is across the southern states into the mid MS Valley, however subtle disturbances are in the flow moving along the ridge.
Temperatures will remain in the low to mid 80s all week.
The forecast starts off with an upper ridge building over the OH River Valley, with SW flow aloft over the central U. A warm front in southern IL will lift north through the area tonight. This will be an afternoon/evening event, with storms developing ahead of a cold front that will push south across the area Monday night. The rest of the week looks to be warmer than average with highs in the upper 70s to mid 80s.
A few light showers may continue past midnight near the WI state line with the highest chances remaining across the far western portions of the UP and Lake Superior.
1127 PM EDT Sat May 6 2023 A ridge of high pressure extending through the eastern part of PA will bring mainly clear skies through early tonight followed by increasing clouds late.
One wave developed just to the west of the Lower Keys with a second wave developing off the southeastern Florida coastline and both drifted southwest. Due to a stronger surface gradient being imparted by the high pressure cell moving southeast and south across the western Atlantic, had to up the winds for today. Meanwhile, mean low level ridging across the Southeastern US and western Atlantic will maintain enhanced moisture in the low levels today. At the same time, upper level ridging will remain parked just to our west with the Florida Peninsula and Florida Keys in broad cyclonic flow aloft.
A warm front advances farther northeast between today and Sunday, but stalls over northeastern Michigan as it can't advance much farther with high pressure in its way. An increase in moisture provides a higher floor for temperatures tonight keeping them securely above 50 degrees, which is 5 to 10 degrees warmer than last night. Flow across the United States is fairly zonal not allowing for any strong low pressure systems to form, but does become more conducive for lingering convective complexes to arrive from the west. One thing of note for midweek is that, on Monday, a weak low pressure system looks to move through and the warm front over the northeastern Great Lakes looks to dive south as cold advection takes over behind the low.
A few storms may develop in the afternoon along the warm front where hodographs look particularly dangerous. Possible initiation along the trailing cold front would wait for a mid- level impulse late in the afternoon / early in the evening.
344 AM CDT Sun May 7 2023 Forecast challenges in the short term include: -convective chances mainly out west river this evening and Monday afternoon/evening (strong wind gusts?) -impacts of low cloud cover on temperatures today and Monday At 3 AM CDT, skies were a mix of low clouds and clear sky, with the low clouds steadily increasing in areal coverage throughout the CWA as they move from north to south on the backside of the upper circulation that moved up into North Dakota earlier. Temperatures on Monday may again only end up topping out in the 60s to perhaps the low 70s across much of the region.
(Today through Monday) High pressure will continue over the Western Atlantic waters today into tonight keeping a breezy easterly wind flow in place. The short range models have also weaken the mid-level trough over the southern Gulf coast states and now does not show it moving through South Florida today. On Monday the high will weaken while shifting southward while extending westward over South Florida. Temperatures will be increasing a little bit during this time with highs in the lower to mid 90s for most areas, except around 90 east coast metro areas.
1254 AM EDT Sun May 7 2023 A ridge of high pressure extending through the eastern part of PA will bring mainly clear skies through early tonight followed by increasing clouds late.
The persistent jet stream passing overhead around the broad area of cyclonic circulation anchored over western North America continues to replenish moisture supplies just enough to keep a few showers active over the high terrain of the West Slope this morning. Flow begins to turn more southwesterly Monday as the trough along the West Coast begins to deepen. Weak ridging will build ahead of the deepening trough and begin a multi day warm up to start the work week. The building ridge will put jet forcing well to our north Monday afternoon.
No changes to the forecast as of of yet, but this unexpected outflow may also push the warm frontal placement, and stronger convective potential, farther south later today. Northward recovery of the warm front later today is uncertain.
A moisture/instability axis aligned generally SW-NE in the lower/mid Miss Valley, has caused backward propagation of convection to develop along the line. It was noted that the low- level support may weaken a bit through the late morning into the afternoon as the initial low-lvl jet moves off to the ENE.
647 AM CDT Sun May 7 2023 (Today through Monday) The ridge remains in place today, so precipitation will be more like summertime activity with the pop up hit and miss variety through early evening.
High pressure initially near the Mid Atlantic coast will shift eastward into the western North Atlantic over the next several days.
(Today through Monday) The upper level ridge currently over the region will weaken today giving way to more of a zonal flow by tomorrow morning. While at the surface, high pressure will remain just off the Carolina coast. Late this morning the larger dirty ridge pattern will aid in the development of MCS activity to our north.
Forecast challenges in the short term include: -convective chances mainly out west river this evening and Monday afternoon/evening (strong wind gusts?) -impacts of low cloud cover on temperatures today and Monday At 3 AM CDT, skies were a mix of low clouds and clear sky, with the low clouds steadily increasing in areal coverage throughout the CWA as they move from north to south on the backside of the upper circulation that moved up into North Dakota earlier. Temperatures on Monday may again only end up topping out in the 60s to perhaps the low 70s across much of the region.
647 AM EDT Sun May 7 2023 High pressure and offshore winds will allow for warm weather today. Some showers will clip southern portions of the area tonight followed by a dry cold front passing Monday.
This will keep the higher chances for showers today in the north half of the fcst area as anticipated. This upper low will slowly transition north thru today. This will keep chances for showers all day into tonight for northern 1/2 of the fcst area while southern 1/2 of the fcst area is on the south side of upper low and a bit drier airmass.
Upper level analysis shows ridge over the Great Lakes region to the southeast US, with trough over the Pacific NW.
Moving ahead to Monday, some of the high-res guidance as well as operational models suggest we could be dealing with another MCS- type complex as our dirty SW flow regime maintains its presence. For now, have leaned toward the warmer NBM temps for Monday compared to the cooler MOS guidance but this could certainly change if we end up dealing with more widespread convection. When combined with the humidity, this could result in uncomfortable conditions, as heat index values would climb into the low to mid 90s.
Have a wonderful Sunday! (Today through Monday) High pressure will continue over the Western Atlantic waters today into tonight keeping a breezy easterly wind flow in place. The short range models have also weaken the mid-level trough over the southern Gulf coast states and now does not show it moving through South Florida today. On Monday the high will weaken while shifting southward while extending westward over South Florida. Temperatures will be increasing a little bit during this time with highs in the lower to mid 90s for most areas, except around 90 east coast metro areas.
Not much motion is expected over the next few hours as warm air advection aloft is rather weak, so surface pressure falls aren't anticipated to be too significant with this low. This will keep the higher chances for showers today in the north half of the fcst area as anticipated. This upper low will slowly transition north thru today. This will keep chances for showers all day into tonight for northern 1/2 of the fcst area while southern 1/2 of the fcst area is on the south side of upper low and a bit drier airmass.
We remain in a weakly-forced regime of ample deep moisture beneath mid/upper ridging, with rain chances driven somewhat diurnally and somewhat by the influence of periodic convective complexes.
Dry conditions, warmer high temperatures and afternoon breezes are expected through Monday.
As the closed low moves towards the area from the west, expect isolated showers to develop over the marine waters this morning and along the coast and inland from the Cascades east early this afternoon. Shower activity will gradually increase late this afternoon through tonight as the low approaches the coast. Models show good agreement that the closed low will move onshore near the Oregon-California border early Monday morning then slowly track inland along and just north of the Oregon-California border during the day Monday. With the timing of the low moving onshore Monday morning and models indicating weak instability and CAPE developing across inland areas by mid/late morning, have expanded the slight chance for thunderstorms into the mornings hours.
228 AM PDT Sun May 7 2023 Dry and a little warmer today and Monday but still a few degrees below normal for early May.
Key Messages - Near record high temperatures are forecast once again this afternoon with readings in the lower 90s.
Dry weather associated with high pressure conditions will persist on through today and tonight as high level ridging influences the pattern from out of the west and low level ridging associated with direr air continues to extend in from out of the east. High temperatures this afternoon will be in the lower to mid 80s for most inland areas with max temps reaching up into the mid to upper 80s for areas along and west of the I-75 corridor.
Gusty winds will be the main issue with the storms as the lower levels are pretty dry.
(Rest of today through Monday) South Florida sits on the periphery of a surface area of high pressure that is centered over the Atlantic waters off the Carolinas. As this high slides southward, a moisture gradient is moving across the southern peninsula of Florida. The additional cloud cover today will keep temperatures relatively cool along the eastern half of the peninsula but heading towards the Gulf coast, things will get less cloudy and warmer due to more abundant sunshine. Drier air behind the boundary should keep convective activity limited as the mid-level pattern places a ridge over the area. Less cloud coverage on Monday will lead to warmer temperatures compared to today with lower to mid 80s near the Atlantic and lower 90s in Southwest Florida.
Highs this afternoon and Monday will be mainly in the 50s and 60s with lows tonight and Monday night mostly in the low 40s.
340 PM CDT Sun May 7 2023 Pesky low pressure at the sfc and aloft continues to slowly spin across the ND/MN border region throwing low clouds and rain westward across ND. The low clouds remained tough all day long around Pierre, but now have broken and are fading. Peak heating this afternoon in combination with lee side troughing in the higher terrain of the Black Hills will kick off some convection. A ridge of high pressure and the presence of a cooler air mass will aid in temps falling into the 40s by daybreak Monday. Weak sfc ridging will remain over parts of the area. However, chances will remain on the low end so anticipate most areas will remain dry.
300 PM EDT Sun May 7 2023 As of 15Z surface analysis, a center of high pressure is located off to the southeast of the forecast area.
A weak cold front moving into the forecast area from the north should limit the northward extent of that potential as well as possibly serving as the focus for convective development late tomorrow.
With weak upper forcing, could see development later tonight in Iowas/northwest Illinois that could then ride the ridge and theta-e gradient down into northwestern Indiana and head southeast from there, and this is the prevailing thought that went into the forecast Pops. A cold front will be moving through at the start of the period with numerous showers and storms expected ahead of the boundary. Confidence remains low due to the low-predictability pattern in the short term period. The cold front should move south of the area by late Monday night with mostly quiet conditions expected. Look for slightly cooler lows in the 50s as cold air advection filters in.
This is one of those times be on alert even during the wee hours of the morning! Monday: A cold front arrives pushing the thunderstorm threat eventually east and southward and the severe threat has been pushed south of the dvn cwa. It will be cooler with highs in the upper 60s north to upper 70s south.
407 PM EDT Sun May 7 2023 A wave of low pressure will track south of the region tonight bringing a few rounds of showers. High pressure builds into the region with a frontal boundary to our south for the first half the week.
That being said, conditions do not appear overly favorable in the lowest levels given the amount of dry air present and lack of 0- 1 km shear, suggesting that the threat for tornadoes should remain rather low.
After midweek, a cold front is expected to stall over the area that will likely increase the chance of showers and thunderstorms even more.
324 PM EDT Sun May 7 2023 Some showers will clip southern portions of the area tonight as low pressure passes to our south. This low will be followed by a dry cold front passing Monday.
115 PM PDT Sun May 7 2023 Dry and a little warmer today and Monday but still a few degrees below normal for early May.
The general short term pattern is showers and thunderstorms both this evening and Monday afternoon and evening as waves continue to eject from the upper trof to the west.
Drier and somewhat cooler air returns mid week. Effective warm front has been pushed well south of the area with the main bowing segment (sub severe at this time) diving well SE of our area and the northern flank of the line now getting ready to move into White county.
A slow moving low pressure circulation continues to move northward out of north central Montana into Canada this afternoon. Meanwhile, another low pressure system moving through central Idaho will swing northwards into southwest Montana this afternoon and evening.
MLCAPE values this afternoon are expected to range from 500-1500 J/kg, with the higher values over the western portion of the area, then MLCAPE values of mostly near 500 J/kg are expected for tonight before increasing to 1000-1500 J/kg on Monday.
(Tomorrow through Sunday) Warm and humid conditions continue Monday with the storm focus being along a cold front and/or outflow boundary which will likely be near far NE OK into NW AR by late Monday afternoon or evening.
Showers and a few thunderstorms within the warm air advection arm in advance of this low have already moved east of the region. At most, expect an isolated shower or two to begin this forecast late today from enhanced low level convergence around this low/front.
249 PM EDT Sun May 7 2023 Upper air pattern consists of a weak 500 mb ridge over the Great Lakes region with a trough in the western U. Some additional rain showers may just be able to scrape our southern and western zones with the upper trough over northern MN and another embedded wave currently over the MN/IA border expected to move into WI by early Monday. A few light showers may continue past midnight near the WI state line with the highest chances remaining across the far western portions of the UP and Lake Superior.
353 PM CDT Sun May 7 2023 A cold front will pass across western Kansas tonight. Expect lows mainly in the 50s, with cooler highs in the 80s Monday.
Showers and the highest winds have been favored across the Upper Keys, while the cumulus streamer in the lee of the Lower Keys has remained mostly dormant. Temperatures across the island chain are in the mid to upper 80s, and dewpoints are back in the lower 70s.
Main forcing for this complex of storms is a wave/jet streak riding the top of the ridge over Kentucky/northern Tennessee valley. Due to the low Wet Bulb Zero around 9kft and decent mid-level lapse rates, the strongest storms could produce small hail.
This storm should act to reinforce the low level boundary near the I80 to Highway 30 corridor late this afternoon with the boundary acting as a focus for convection.
Winds remain fairly weak with this low thanks to the occlusion widening out the pressure gradient.
By the end of the week, a ridge of high will build over the region, allowing temperatures to climb to above-normal levels.
134 PM PDT Sun May 7 2023 Slightly warmer today and Monday, with breezy onshore winds occurring each afternoon and evening in the mountains and deserts. Persistent troughing will maintain a healthy marine layer, with night and morning low clouds extending into the valleys the next several days.
A warm front will lift north toward or just into our northwest Wisconsin zones this afternoon. Some lakeside areas may struggle to reach the lower fifties. Chances for showers/thunderstorms increase some tonight and continue into Monday with an upper trough remaining over north to northwest Minnesota.
1219 PM CDT Sun May 7 2023 (Today through Monday) The ridge remains in place today, so precipitation will be more like summertime activity with the pop up hit and miss variety through early evening.
Pattern Synopsis/Forecast: Early this afternoon, filling low pressure across northwest MN continues to weaken with a stationary/warm front extending across WI into southern/central MI. Secondary low pressure over the central Plains with a more potent warm front draped across IA/IL/Michiana. Building high pressure across Hudson Bay and that sharpening warm front to our south will aid in bringing continued that east- northeast flow this evening with continued damp conditions possible, especially for areas east of I-75.
318 PM EDT Sun May 7 2023 As of 15Z surface analysis, a center of high pressure is located off to the southeast of the forecast area.
1109 AM EDT Sun May 7 2023 High pressure and offshore winds will allow for warm weather today. Some showers will clip southern portions of the area tonight followed by a dry cold front passing Monday.
157 PM MDT Sun May 7 2023 Main forecast challenge in the near term is identifying the corridor with the highest potential for one or two severe storms this afternoon and evening.
Wind shear is only expected to be around 20 to 25 kts, which will lead to some organization of the storms with the higher end instability values.
Pesky low pressure at the sfc and aloft continues to slowly spin across the ND/MN border region throwing low clouds and rain westward across ND. The low clouds remained tough all day long around Pierre, but now have broken and are fading. Peak heating this afternoon in combination with lee side troughing in the higher terrain of the Black Hills will kick off some convection. A ridge of high pressure and the presence of a cooler air mass will aid in temps falling into the 40s by daybreak Monday. Weak sfc ridging will remain over parts of the area. However, chances will remain on the low end so anticipate most areas will remain dry.
1043 PM EDT Sun May 7 2023 Some showers will clip southern portions of the area tonight as low pressure passes to our south. This low will be followed by a dry cold front passing Monday.
732 PM EDT Sun May 7 2023 Mainly dry weather continues through tonight as high pressure remains near the East Coast.