Aikyam-Lab/Synoptic-Bench huggingface dataset:
Precipitation may linger over the southern half of the forecast area through Monday afternoon, and with the rain and cloud cover, high temperatures tomorrow will be notably cooler in the lower to middle 80s. High pressure should keep things for much of Tuesday, before isentropic ascent and several low amplitude waves projected to move through the Central Plains brings periodic precipitation chances mid/late week. Despite the low coverage there will not be any period for the next 12-20 hours that will be prevailing dry conditions.
325 AM CDT Mon Jul 27 2020 A pleasant start to the work week today, with high pressure working across the Tri-State area. Light and variable winds continue through the day, thanks to the aforementioned high pressure. However, some areas along and near the Buffalo Ridge could see some gusts around 20 knots this afternoon with slightly better mixing potential.
18Z Surface observations and RAP analysis indicated pre frontal trough across the southeast corner of the forecast area. Observations as well as visible satellite indicate cold front steadily advancing south and was located between Wray and St Francis. Already have convective initation along trough and with continued forcing along front expect storms to steadily increase in coverage through the afternoon. Fog, low stratus and cooler temperatures will build into the area in the morning which will diminish precipitation threat. Long range guidance suggests that WNW to NNW flow aloft will prevail over the Central/Northern Plains in this period -- on the N-NE periphery of an amplifying upper level ridge over the Desert Southwest/Intermountain West.
Ridging aloft continues today, and with a low and mid level theta-e ridge axis in place, we see isolated to widely scattered afternoon and evening showers and thunderstorms forming, mainly west of Interstate 25.
405 AM EDT Mon Jul 27 2020 High pressure will remain anchored south and east of the area for the early portion of the week. A cold front will move across the area mid-week and settle to the south during the second half. Upper level ridge will break down today under pressure from digging mid-upper level trough over the Great Lks region. Heat indices expected to remain below criteria in the low 100s east of the Blue Ridge and below 100 west. Digging mid-upper level trough over the Great Lks and Mid- Atlantic states will drive a cold front through the area Tue night. At mid-upper levels, a closed low centered over Quebec will be slowly progressing off toward the east, leaving us in zonal flow to its south.
216 AM MDT Mon Jul 27 2020 MORNING DISCUSSION: Synoptic Setup: Forecast begins with a hot high pressure developing into a large heart dome ridge over the western third of the CONUS. An extension of this ridge juts north into souther British COlumbia and Alberta. On either side sits large troughs over Manitoba and the Alaskan Panhandle. Northeast Montana lies in between airmasses on the warmer side of northwest flow aloft. Today through Tuesday: Ridge pressing in from the west will generate hot dry conditions as the ridge axis topples east across the region.
1148 PM CDT Sun Jul 26 2020 Surface analysis at 1 pm has a cold front sagging southeast, currently extending from central WI into northeast IA. Radar pretty quiet right now but expecting a broken line of showers/storms to form along the cold front as it progresses southeast through the rest of the area. Front and associated storms expected to push south of the area this evening as refreshing Canadian high pressure pushes in. Cooler/much drier airmass over the area through Monday with northwest winds in the the 10 to 20 mph range. The upper level low currently over central Manitoba will track slowly to the east allowing the upper level ridge to build back over the northern Rockies into the High Plains.
246 AM EDT Mon Jul 27 2020 Upper air pattern consists of a 500 mb trough over the upper Great Lakes this morning with a closed low over northern Ontario and both digs to the southeast this forecast period.
The upper lvl flow pattern acrs the Mid-South wl cont to transition to NWLY in the coming days, as upper ridging gradually blds acrs the WRN States.
1129 PM CDT Sun Jul 26 2020 Morning stratus is breaking up quickly this afternoon as the cold front continues to push southeast away from the area. Dew points will drop from the low to mid 70s into the 50s this evening, which is where they will stay until further notice. Weak ridging is in place over the Rockies and High Plains while a southwesterly jet is flowing onshore to the central California coast.
High temperatures are expected to be in the low to mid 90s with afternoon heat index values in the low 100s. Convection will gradually diminish after sunset with overnight lows in the low to mid 70s.
133 AM EDT Mon Jul 27 2020 High pressure will maintain dry through this morning before showers and thunderstorms return from the west this afternoon. Broad ridging should shift east overnight in response to a digging northern Plains trough, supporting warm, moist advection within SW flow. upper ridging flattens and is replaced by upper troughing across the Great Lakes. A sfc cold front will accompany this initial wave and track ESE across the area late Monday through Tuesday, with showers and thunderstorms expected through much of the same period. Further movement of the front south plus loss of heating should move most convection out of the region by Tuesday night, save for a lingering shower over the ridges. Hot and humid conditions will make Monday the warmest of the week, before drier/cooler air filtering in behind the front provides more seasonable temperature Tuesday.
152 AM EDT Mon Jul 27 2020 An upper ridge Today will suppress widespread convection. Morning low temperatures remaining mild, with readings in the lower 70s. Today: Weak upper ridge will still reside over the area through the day. Further north, an upper trough will be pushing towards the Great Lakes. An upper trough will move towards the northeastern states Tuesday. This will drive a cold front into the OH/TN Valley region Tuesday. Subtropical high pressure will ridge into the forecast area at the surface.
345 AM EDT Mon Jul 27 2020 A cold front will be the focus for showers and thunderstorms today into Tuesday.
The sfc cold front that was the focus for storm development yesterday afternoon is currently entering far northern Kansas. In addition, the cold front progresses southward through the morning and afternoon. Model QPF consistency is low given the varying solutions on precip coverage, but believe that the heavy rain potential is isolated and focuses south of the highest observed rainfall from earlier this evening. Lingering showers and isolated thunder may be impacting areas south of Interstate 70 on Tuesday morning, otherwise most of the area should be dry during the afternoon as cooler, more pleasant temps rise to the low and mid 80s.
Cold front pushes across the area later tonight, but instability will be diminishing so not expecting too much fanfare. It will be cooler and much less humid as dewpoints drop into the middle 50s (north) and lower 60s (south). Models signaling isolated showers across northern WI in the mid-late afternoon hours during peak heating as a upper trough sinks southeast from Canada. Limited moisture and weak subsidence in the lower levels should keep any activity pretty few and far between. 850mb temps drop into the lower teens, supporting highs in the upper 70s in the Northwoods and the lower 80s and the Fox Valley.
As models have advertised the past few days, satellite imagery is now confirming a well defined upper trof along the lower Mississippi River. Better coverage of showers and storms expected on Tuesday as the upper trof axis pulls deeper moisture farther inland into Alabama. The higher coverage of rain and cloud cover on Tuesday will keep highs in the middle to upper 80s.
302 AM EDT Mon Jul 27 2020 An U/L ridge will hold over the Gulf of Mexico and Florida through the period creating broad large scale subsidence across the region.
temperatures are ranging from the lower to mid 70s across the area tonight and should not drop much more from that. A weak upper level low continues to meander over south central Louisiana, and will be the main focus for shower and thunderstorm development on Monday.
123 AM EDT Mon Jul 27 2020 The area will remain between high pressure to the east and low pressure inland through the week. Temperatures in the low to mid 70s appear on track. In addition, a weak upper low/trough is expected to move north along the coast through Tuesday.
236 AM CDT Mon Jul 27 2020 A cold front will push southeast into the area today, bringing scattered showers and thunderstorms.
High pressure continues through the short term forecast period. Broad closed cyclone will slowly shift into southern Ontario with mid-level heights beginning to rise over the Northern Plains as an upstream ridge builds. With a ridge building, temperatures should be slightly warmer than yesterday in the west with highs in upper 70s north to upper 80s southwest. Lows going into Tuesday morning should again be mostly in the low to mid 50s with a few spots reaching the upper 40s possible. Conditions stay dry on Tuesday during the day as the aforementioned ridge drifts over the region.
109 AM EDT Mon Jul 27 2020 Heat and more oppressive humidity are expected Monday and Tuesday as high pressure builds over the region. A cold front will move to just north of the area by midweek and linger in the region into the weekend. A mostly clear night is expected to continue with high pressure ridging in from offshore.
As the day progresses on Monday, expect a cold front dropping through Illinois and Indiana to finally approach our area of responsibility. By Monday night, the cold front associated with the closed low over Ontario is forecast to begin pushing into the southern IN/northern KY region. The front is then expected to continue sinking southward across the area Tuesday, eventually stalling out somewhere over the lower OH Valley/TN Valley and remaining in the vicinity through the week.
235 AM MDT Mon Jul 27 2020 It's been a rare cloudless night across the state of Montana as prominent upper ridging continues to build into the area, which combined with dry low-levels is helping to produce another cool night. Going into today, ridging will persist. Temperatures will rise back into the lower 90s, and relatively low dewpoints possibly dropping into the upper 30 will bring about humidities in the mid teens by the late afternoon.
High pressure building over the desert southwest by the midweek will bring much warmer temperatures and a downturn in monsoon activity. Another round of convection is forecast for Monday, with the highest chances primarily east of I-17 and Highway 89. Currently there are isolated to scattered showers and thunderstorms over the higher terrain east of a line from Prescott AZ to Kanab UT. Water vapor images show the dry air from the southern flank of of the low off the California coast intruding into western Arizona. High pressure builds in over the Desert Southwest bringing clear skies and warmer temperatures through the week.
The high pressure ridge near the SE Atlantic coast weakens slightly, retreating to the east. Convection is expected to initiate in the higher terrain of the mountains and Plateau around noon, and spread into the Valley through the afternoon.
Quiet conditions are expected today as drier are moves in behind the front and high pressure builds to our west. Clouds will gradually clear with highs expected to be in the low to mid 80s. Some low level convergence looks to set up between the high pressure to our south and the low pressure to our northeast.
Temperatures range from the lower 60s to the lower 70s. As the surface cold front moves through the region this morning, more comfortable dew points (in the 50s) will move into the region. With 850 mb temperatures about 3 to 4C cooler this afternoon, high temperatures will only range from the mid-70s to mid-80s. With drier dew points across the region tonight, low temperatures on Tuesday morning will range from the lower 50s to lower 60s. During this time, a low pressure system will move eastward through southern Canada towards the northeast coast of the US. The patchy fog should stay to the south ahead of the cold front.
The wave is associated with sfc and upper level low pressures in far nrn Ontario. All of the better showers and storms were out ahead of the lows in southern Hudson Bay, as well as, nrn Il back through the central Plains. This will help push the cold front through this morning, drawing in cooler and less humid air. Pattern synopsis/forecast: A broad long wave trough will linger over the Great Lakes region throughout the forecast period. As a short wave rotates around the long wave trough with associated moisture. Troughing gradually begins its slow exit to the east as we head through the remainder of the work week as heights begin to rise locally heading into the upcoming weekend.
536 AM EDT Mon Jul 27 2020 An upper ridge Today will suppress widespread convection. Morning low temperatures remaining mild, with readings in the lower 70s. Today: Weak upper ridge will still reside over the area through the day. Further north, an upper trough will be pushing towards the Great Lakes.
Temperatures are expected to return to just below seasonal, in the mid 80s, for Tuesday while we're briefly under the influence of ridging aloft.
421 AM PDT Mon Jul 27 2020 A weak trough aloft will keep us seasonally warm through Monday, with night and morning, coastal low clouds and fog. Additional warming is expected this week as a strong ridge builds over the Southwest. The baggy persistent upper level trough remains along the west coast this morning, and today will be the last day with slightly below normal temperatures, as the trough begins to exit and weaken as it moves to the northeast. On Tuesday the subtropical ridge will begin to build west from the Southern Plains towards the Southwest.
This along with an upper level Low over central and western portions of LA will bring increased lift and instability into the area with locally heavy rainfall possible throughout the daytime hours today. temperatures will remain very pleasant again today with highs only in the low to mid 80s. upper level trough will begin to drop into the western Great Lakes beginning today. Upper level trough will move eastward towards the northeastern USA by the middle and latter part of the week. Upper level high pressure will expand and slowly drift westward through the Gulf during the middle and latter part of the week bringing a drying trend with conditions returning to more typical summer conditions.
540 AM CDT Mon Jul 27 2020 A cold front will push southeast into the area today, bringing scattered showers and thunderstorms.
Temperatures range from the lower 60s to the lower 70s. As the surface cold front moves through the region this morning, more comfortable dew points (in the 50s) will move into the region. With 850 mb temperatures about 3 to 4C cooler this afternoon, high temperatures will only range from the mid-70s to mid-80s. With drier dew points across the region tonight, low temperatures on Tuesday morning will range from the lower 50s to lower 60s. During this time, a low pressure system will move eastward through southern Canada towards the northeast coast of the US. Skies are clearing behind a cold front this morning.
Expect one more day of a typical summertime weather before a cold front starts to work its way into the region Tuesday.
405 AM CDT Mon Jul 27 2020 Early morning sfc analysis shows high pressure centered over the sern CONUS with a weak coastal trof noted along the TX/swrn LA coastline at this time. 2 inches which is higher than the 90 percent moving average for the date per SPC) is already producing quite a bit of convection over the near shore coastal waters and adjacent coastal zones with some rainfall already spreading into the lower Atchafalaya Basin.
939 AM EDT Mon Jul 27 2020 Weak southwest winds in the lower levels will exist over much of the area today, as ridge axis remains near the Lake Okeechobee region. Otherwise, with the ridge axis near Lake Okeechobee a light offshore flow this morning will become southeasterly around 10 kt once the seabreeze develops this afternoon.
534 AM MDT Mon Jul 27 2020 500mb RAP analysis and satellite imagery showed a trough spanning the northern Plains and Upper Midwest early this morning. Behind the trough, ridging continued over the Four Corners region to the Pacific Northwest. This placed the region under northwest flow aloft, with an area of high pressure across western New Mexico. Northwest flow persists on Monday with the upper trough sliding east and high pressure over the southern Plains and Desert Southwest. High temperatures will be slightly cooler, in the upper 70s to low 80s.
630 AM EDT Mon Jul 27 2020 An upper ridge Today will suppress widespread convection. Today: Weak upper ridge will still reside over the area through the day. Further north, an upper trough will be pushing towards the Great Lakes.
556 AM CDT Mon Jul 27 2020 Scattered showers and storms are developing and moving through northeast and central MO and west central IL early this morning south of a cold front extending from WI southwest through southern portions of Nebraska and Iowa. This cold front will drop southward through our forecast area today and tonight as the upper level trough over the Northern Plains deepens as it moves eastward through the Great Lakes region. By 12Z Tuesday the cold front should be near the MO and AR border with slightly below normal low temperatures for northeast and central MO and west central IL tonight along with much lower humidity/surface dew points.
Northern California finds itself nestled between a ridge positioned to our east in the Rockies and a trough just to our west. Upper level ridge then builds off the southern California coast on Tuesday as much of the northern Pacific is influenced by an upper level trough.
704 AM CDT Mon Jul 27 2020 12Z TAFS Widespread showers already ongoing ivo LFT and ARA this morning in response to a broad upper trof extending from the remnants of Hanna across the northwestern gulf and through the region. /issued 405 AM CDT Mon Jul 27 2020/ Early morning sfc analysis shows high pressure centered over the sern CONUS with a weak coastal trof noted along the TX/swrn LA coastline at this time. 2 inches which is higher than the 90 percent moving average for the date per SPC) is already producing quite a bit of convection over the near shore coastal waters and adjacent coastal zones with some rainfall already spreading into the lower Atchafalaya Basin.
918 AM EDT Mon Jul 27 2020 A cold front will be the focus for showers and thunderstorms today into Tuesday.
421 AM PDT Mon Jul 27 2020 (Corrected WWA section at the very end) A weak trough aloft will keep us seasonally warm through Monday, with night and morning, coastal low clouds and fog. Additional warming is expected this week as a strong ridge builds over the Southwest. The baggy persistent upper level trough remains along the west coast this morning, and today will be the last day with slightly below normal temperatures, as the trough begins to exit and weaken as it moves to the northeast. On Tuesday the subtropical ridge will begin to build west from the Southern Plains towards the Southwest.
Ludwig An upper level ridge of high pressure will reside over the northern Rockies this week. For this afternoon, expect some monsoonal moisture to start to work its way up into Southwest MT, as upper level disturbances rotate around the Great Basin area of high pressure. As a result, afternoon temperatures over Southwest MT will be a touch cooler on Tue, while hot temperatures continue over North Central MT.
With the synoptic cold front lagging slightly behind a mesoscale outflow boundary roughly across central Kansas and northern Missouri, this will be the general impetus for the next few hours for showers to continue. Weakly driven isentropic ascent over the low level cooler air will continue to drive the precipitation through the morning hours.
Upper level flow from the northwest will continue as a ridge over Colorado retrogrades west. At the surface, high pressure currently centered across central Nebraska will gradually shift eastward today with return southerly flow developing across western Nebraska late this afternoon on the back side of the high. Dew points will be more comfortable in the 50s as drier air mixes downward due to subsidence associated with the high. The exception will be across far northwestern Nebraska, where southeasterly upslope flow could support an isolated thunderstorm moving southeast off the higher terrain late this afternoon. Temperature wise, highs today will be in the low to mid 80s to the north of a stationary front across Kansas. Lift associated with this disturbance combined with southeast upslope flow will create an environment for scattered thunderstorms on the higher terrain in Wyoming and Colorado.
And a cold front is moving into northwest Oklahoma which will also create a focus for storm development. There is still some question on where in northern or central Oklahoma the heaviest rain will develop and that will depend on where the surface cold front (and any outflow boundaries) are located, and in the short term will also depend on the movement of the MCV in southwest Kansas.
Very warm high pressure will be present over the Northern Rockies throughout this week. A trough of low pressure developing along the Pacific Northwest coast during this weekend is expected to eventually move inland (eastward) and bring a cool, showery airmass over the Northern Rockies for at least the first half of the following week. The recent trend for the global models has been to delay the trough, however.
430 AM MDT Mon Jul 27 2020 Aviation Section Updated An upper level ridge of high pressure will reside over the northern Rockies this week. For this afternoon, expect some monsoonal moisture to start to work its way up into Southwest MT, as upper level disturbances rotate around the Great Basin area of high pressure. As a result, afternoon temperatures over Southwest MT will be a touch cooler on Tue, while hot temperatures continue over North Central MT.
Have thus covered the higher probability periods for showers at each site with accompanying TEMPO or PROB30 groups carrying this potential for moderate to heavy rain. Upper ridge continues to move to the west, with northwesterly flow aloft coming into place over the Panhandles. Chances for development will increase through the afternoon as the upper ridge continues to exit to our west.
310 AM MDT Mon Jul 27 2020 500mb RAP analysis and satellite imagery showed a trough spanning the northern Plains and Upper Midwest early this morning. Behind the trough, ridging continued over the Four Corners region to the Pacific Northwest. This placed the region under northwest flow aloft, with an area of high pressure across western New Mexico. Northwest flow persists on Monday with the upper trough sliding east and high pressure over the southern Plains and Desert Southwest. High temperatures will be slightly cooler, in the upper 70s to low 80s.
Upper level troughing continues to dominate the west coast and the weather around the Bay Area. We're watching a building ridge out of the desert southwest for late week and in through the weekend to bring a return to heat. However, a deepening upper trough digging in from the northwest may suppress the advancing ridge. Operational atmospheric models seem to be in good agreement with the ridge making it into our southern service area of Monterey and San Benito Counties, but the onshore flow may be strong and cool enough to limit significant heat impacts. This weekend as the ridge noses northward we'll see that marine layer compress under that high pressure, which should help clouds to burn off sooner, not have as far inland movement, and later onset. SFO Bridge Approach.