Aikyam-Lab/Synoptic-Bench huggingface dataset:
Upper level low pressure system over the IN/KY border forecast to move into northern IN by Sat afternoon. Elsewhere an upper level ridge axis from the Dakotas to SASK will shift into MAN by Sat afternoon.
523 PM MDT FRI SEP 30 2016 An upper level short wave trough moves through the apex of the persistent upper ridge in place over the high plains region during the day on Saturday.
although have gone at or a bit below the lowest guidance numbers. Ohio Valley upper low will finally lift northeast.
820 PM EDT Fri Sep 30 2016 Upper level low pressure will continue to produce bands of showers across the region into the weekend. Closed low will continue to spin across the lower Ohio Valley through the period with a slow wobble toward the north.
1006 PM EDT Fri Sep 30 2016 A large upper level low pressure system will lift slowly northeast across the Great Lakes region through the weekend.
Coverage will increase and spread northward overnight ahead of an approaching upper low and accompanying cold front. Cold front is located across east-central Oregon this evening and will push into southwest Idaho around midnight.
1026 PM MDT Fri Sep 30 2016 Narrow band of showers progressing east across the Panhandle now in association with a weak upper impulse lifting northeast over the high plains. Continued quite mild across the CWA Saturday under an upper ridge axis situated over the high plains/central Rockys.
An upper level short wave trough moves through the apex of the persistent upper ridge in place over the high plains region during the day on Saturday.
Overnight low temperatures will mainly be in the mid to upper 50s, although a few low lying areas and river valleys may drop into the lower 50s. Slightly warmer temperatures are forecast on Saturday with highs mainly in the low to mid 80s, with light south winds.
These winds along with a canopy of opaque cirrostratus arriving from southeast NM should serve to keep a decent lid on min temps overnight - about 5 to 10 degrees warmer than this morning. Temporary erosion of an upper ridge during this time will provide some background ascent, but muted forcing overall should keep storms on the spotty side. Persistent upper low should be positioning just north of the Ohio Valley tomorrow evening with our next storm system of interest just offshore the Pacific Coast.
/issued 247 PM CDT FRI SEP 30 2016/ Only change from 24 hours ago is a bit more sun and warmer temperatures across the far north.
Pieces of energy rotating around the upper level cut-off low is producing isolated/scattered showers over parts of eastern Wisconsin and Illinois per latest mosaic radar. 12z GFS/NAM/ECMWF are in good agreement in lifting upper level closed/cut-off low into the Great Lakes Region tonight into Saturday. A series of impulses wrapping around the upper level cut-off low will continue to advect moisture into the area. Upper level cut-off/closed low tracks into the eastern Great Lakes Region Saturday night and allows any isolated/scattered showers to be east of the forecast area.
Southerly winds have been gusty today, as the CWA sits in an area of relatively tight isobars between high pressure to the east and low pressure west.
The upper level low continues to sit and spin near IN/KY this evening.
With skies clearing over a large portion of the area, temperatures are starting to drop into the middle 50s in rural locations and into the lower 60s near urban areas. Chattanooga Airport, TN 54 79 57 81 / 10 10 10 10 Knoxville McGhee Tyson Airport, TN 52 76 56 78 / 10 10 10 10 Oak Ridge, TN 52 75 55 78 / 10 10 10 10 Tri Cities Airport, TN 49 73 51 75 / 10 10 10 10.
Central and Southwest Montana will remain underneath unsettled southwest flow ahead of the low pressure trof over the West Coast.
511 PM MDT FRI SEP 30 2016 A large Pacific low pressure trough off of the Pacific Northwest coast will move inland towards western Wyoming bringing increased clouds and showers with isolated afternoon and evening thunderstorms Tonight and Saturday.
850 PM CDT FRI SEP 30 2016 Large upper low which has been situated over northern Kentucky for the past 24 to 30 hours appears to be inching its way north this evening into extreme southern Indiana.
Still have plenty of VFR bases/ceilings rotating into northern and northeastern Arkansas this evening, on the southwest side of an upper low situated over the Ohio River Valley.
957 PM EDT Fri Sep 30 2016 High pressure will slowly move northeast of the region through the weekend. Low pressure will track south of the Gulf of Maine Saturday night. A high pressure ridge will dominate the weather for the area through the forecast period. The warm front will continue to move north through the period, and by the end of the period will be over southwestern Maine, and the Gulf of Maine. The ECMWF show the low in the same area 6 hours later. Weak low pressure will track south of the Gulf of Maine Saturday night while high pressure remains ridged across the region. The low will bring rain to Downeast areas Saturday night, with the better chances near the coast. High pressure will keep partly cloudy skies across northern areas Saturday night.
Northern plains will generally be under the influence of a broad upper level ridge for the short term, and this will result in mainly dry and quiet conditions tonight and Saturday, with the exception of the northern hills where an isolated thunderstorm or two could occur Saturday afternoon.
A strong upper low pressure system continues to spin its wheels over the Ohio Valley today while a strong upper level moves into the Pacific Northwest. In between these systems, an upper level ridge was gradually weakening today. ranging from the mid 70s in central Kansas to the lower 80s along the Colorado border. Weak upper level ridging will continue in place across the central High Plains Saturday night.
705 PM EDT Fri Sep 30 2016 Upper level low pressure will continue to produce bands of showers across the region into the weekend. Closed low will continue to spin across the lower Ohio Valley through the period with a slow wobble toward the north.
This will allow low/mid level ridge over the Atlantic to nudge back towards Florida and the southeast states.
927 PM EDT Fri Sep 30 2016 Upper level low pressure will continue to produce bands of showers across the region into the weekend. Closed low will continue to spin across the lower Ohio Valley through the period with a slow wobble toward the north.
Stacked low pressure center in place over the Lower Ohio Valley this evening and is bringing a few high based stratocu to parts of the Southern Appalachian Region.
Strong upper closed low continues to spin over the region, with the center currently located over central KY. Models have the low continuing to churn over that region until Saturday morning when it begins its track northward. Before that, lobes of vorticity will pass through the mid state as they swing around the upper low, so continued chances for showers will stay in the forecast through Saturday afternoon.
Upper level low pressure system centered over Louisville, KY continues to spin light to moderate showers into northern Middle TN this evening.
720 PM EDT Fri Sep 30 2016 A stationary front will linger just offshore through the weekend as high pressure builds south. Tonight: The large and deep mid/upper level low centered over Kentucky will slowly begin to lift northward. Meanwhile at the surface, a broad and weak area of low pressure will persist as the main moisture band along the residual front will remain offshore.
610 PM CDT FRI SEP 30 2016 Upper low will begin to slowly lift to the north northeast late tonight. With the clouds lingering over the region, lows tonight will be a few degrees warmer. As for winds, to lighten up and back to the northwest by midday on Saturday as upper low moves away from region.
/issued 132 PM CDT FRI SEP 30 2016/ The last day of September had an upper ridge over the area this morning with a deep low over the Eastern U. and a trough along the NW Coast. This trough will slowly dig down the West Coast before swinging inland.
Pesky upper low that has been slowly wobbling around central Kentucky will drift northward tonight to a position somewhere along the IN/OH border by daybreak Saturday. Models show the upper low continuing on its northward trend, though would not be surprised at it slowing down before making it to Lake Erie, as several models suggest. Those chances should start waning with loss of heating and with our distance from the low Saturday night.
1003 PM EDT Fri Sep 30 2016 A stationary front will linger just offshore through the weekend as high pressure builds south. Convection off the northeast Florida coast along the stationary front has been moving northward, and with small height falls aloft around the large cyclone spinning from Kentucky toward Illinois and Indiana there is a small risk that this activity could skirt coastal sections well after midnight within a S-SW synoptic flow.
One feature of interest over the next 24 hours is a retrogressing upper trough currently centered over the lower Ohio valley. There is a lot of moisture wrapping fully around this upper low and resulting in widespread low to mid level cloud cover as far west as central MO this afternoon. Fog/clouds will also keep morning temperatures slightly warmer in the east but will also make things slower to warm through the morning and have thus reduced the high temperatures a bit in the eastern half of the forecast area. Expansive upper low begins to lift and fill during the evening hours, while a very weak perturbation translates over central and southern portions of Kansas overnight.
ranging from the lower 50s over northern interior counties to the lower 60s at the coast. Max temps on Saturday at or just above normal with highs generally in the low to a few mid 80s across the region.
1252 AM EDT Sat Oct 1 2016 An upper low near the Ohio River will begin to drift north tonight and should be over northern Indiana Saturday afternoon.
A large upper level closed low over the Ohio Valley and a ridge of high pressure aloft from Mexico into the Central and Northern Plains will help spread cirrus around 25-30 kft Southeast around the ridge, while some lower to mostly middle clouds between 6-17 kft rounding the back side of the upper low to the East.
BMickelson Previous short term discussion: Southwest flow aloft will prevail across the region ahead of a deepening Pacific trough.
1101 PM CDT FRI SEP 30 2016 Large upper low which has been situated over northern Kentucky for the past 24 to 30 hours appears to be inching its way north this evening into extreme southern Indiana.
Concur with deterministic output that the upper ridge will remain quasi-stationary over the Region. maximum temperatures Saturday only slightly warmer.
749 PM EDT FRI SEP 30 2016 A cold front will linger near the coast through the weekend with dry and cooler air filtering into the region. Cold front remains along the coast with drier air over the forecast area and temperatures quickly falling. The closed upper low over the ohio valley will shift toward New England. Models suggest weak cold advection but with cool bias for maximum temperatures stayed on the warmer side of guidance with mainly southwest low level flow. Upper closed low will shift east towards New England. Generally clear skies through the period with a few passing mid-level clouds circulating around the closed upper low located over the Ohio River Valley.
Another wave will rotate northward around the persistent Ohio Valley upper low Saturday bringing an increasing chance for showers Saturday afternoon into Saturday evening. During this period, model consensus continues to point towards a gradual opening up/lifting out of the pesky upper low/trough that has been plaguing the region the last several days.
Satellite showing upper low centered just offshore with southerly flow aloft over the region. The upper low will move inland Saturday with partly to mostly cloudy skies and scattered showers.
723 PM EDT Fri Sep 30 2016 An upper low near the Ohio River will begin to drift north tonight and should be over northern Indiana Saturday afternoon.
Aiding vertical development, a short wave in the south-central Gulf of Mexico is evident on water vapor imagery rounding the base of a parked long wave trough. MSLP analyses indicate a weak ridge axis washes out near eastern Florida, with a weak pressure pattern across the Florida Keys and the Southeastern Gulf of Mexico. Given 10 to 15 knots of easterlies in the lower troposphere, and mid latitude infusions above 500 mb, the atmosphere should destabilize overnight.
RAP/HRRR have backed off on coverage of dense fog, however nam12 is a bit more aggressive just to the west of the low cloud area. Manual analysis of 12z upper-air data revealed a deep-layer cyclone over the Ohio Valley, a weak ridge over the southern and central Plains and a substantial trough off the Pacific Coast. An axis of low-level moisture wrapping around the northern and western periphery of the Ohio Valley cyclone is evident in afternoon visible satellite by a westward-expanding strato-cumulus deck across Iowa.
However as the low level flow becomes northeast and east - the gulf convection stays offshore as showers/storms form inland in the afternoon then push toward the Gulf coast late in the afternoon. this will support isolated to scattered coverage with the highest inland and south.
/Issued 420 PM CDT FRI SEP 30 2016/ An upper ridge over the Texas and Oklahoma Panhandles will break down and shift east Saturday as a short wave trough approaches the forecast area from the southern Rockies. The NAM and GFS are beginning to trend towards a drier solution and are leaning more towards the ECMWF in tracking the closed upper low across the Great Basin and into the central Rockies. the GFS was bringing the closed upper low farther south near the Four Corners region.
The pattern over the eastern US has a 500mb cutoff low sitting over the midwest, and a trough over the Gulf. There is also a 500mb ridge over the western Atlantic. The ridge will be the influence for the flow over South Florida this weekend, generally keeping a light wind out of the east. This, and the trough to the west, will help to cause showers thunderstorm to develop each day, with little movement.
620 PM CDT FRI SEP 30 2016 Satellite clearly shows the Low is rotating across the mid Ohio river valley attm. Low clouds will again hang around tonight, even as the Low starts to lift north again, headed back toward the Great Lakes. Tmrw nite, these chances will diminish for good, as the Low finally makes its way back to the Great Lakes.
An increase in mid and high clouds will take place tonight and Saturday as a weak upper level disturbance moves around the upper level ridge in place.
722 PM CDT FRI SEP 30 2016 Manual analysis of 12z upper-air data revealed a deep-layer cyclone over the Ohio Valley, a weak ridge over the southern and central Plains and a substantial trough off the Pacific Coast. An axis of low-level moisture wrapping around the northern and western periphery of the Ohio Valley cyclone is evident in afternoon visible satellite by a westward-expanding strato-cumulus deck across Iowa.
540 PM MDT Fri Sep 30 2016 Narrow band of showers progressing east across the Panhandle now in association with a weak upper impulse lifting northeast over the high plains. Continued quite mild across the CWA Saturday under an upper ridge axis situated over the high plains/central Rockys.
Temperatures will be cooler then last night due to less nocturnal cloud cover. Today and tomorrow a weak upper trough will be slowly moving east through the weak upper ridge over Colorado. At the surface a low pressure center resides over southeast Colorado. The boundary and the clouds resulted in slightly cooler temperatures today. Saturday night the upper level trough will be centered over the Rocky Mountain Region. with a deep upper level low pressure trough just off the west coast of the United States.
Have tweaked overnight low temperatures a bit to match current trends, with some locations already a littler cooler than originally expected. ranging from the lower 50s over northern interior counties to the lower 60s at the coast. Max temps on Saturday at or just above normal with highs generally in the low to a few mid 80s across the region.
Have kept the lower temperatures, especially in the north where low temperatures have been pretty cool.
upper low is not expected to move very much, a bit to the northeast during the short term period.
1001 PM CDT FRI SEP 30 2016 Our period of quiescent weather will continue unabated the next few days with ridging in place along with a very dry low-level airmass.
Ridging aloft will keep the area dry today. However, plenty of moisture will be trapped below the ridge, so clouds will hang around. In addition to the moisture, waves of energy, revolving around the upper low, will also move northward Sunday afternoon. At the surface, low pressure will rapidly develop beneath the upper low tonight and move quickly eastward on Sunday with the strong upper level support.
Cooler and breezy conditions with rain likely over the eastern half of the area tomorrow.
This will keep the snow to liquid ratios very low and there may be areas near the 4 Corners that stay all rain as this pseudo warm front lifts to the north through the early morning hours. only held back from some really impressive amounts by the high liquid content. This region will do better into the day Saturday as the main trough passes through and instability boosts snow rates. There will be a decent break on Sunday as a more substantial ridge moves over the Rockies.
An area of low pressure is forecast to move out of the southern Mississippi valley and across the Ohio and Tennessee valleys tonight and tomorrow. Temperatures will remain well above normal this weekend, with highs expected to top out in the mid to upper 60s today, and the lower 60s on Sunday. Overnight lows should be in the lower 50s. Initially, it will be more blocky, as two deep upper level lows start out affecting the eastern and west third of the U. Eventually, by the end of the work week, these two systems will merge across southeast Canada, allowing for broader troughing east of the Rockies, and a return of more winter-like air.
Dew points will slowly be on the rise, but I don't know if it's going to be fast enough to cause any real widespread fog tonight, especially with the high cloud deck in place.
Surface winds will increase again Saturday in advance of a cold front and approaching upper level storm system. The cold front will move through the area Saturday evening with gusty NW to N winds in its wake. Surface winds will diminish markedly this evening, then increase again Saturday in advance of a cold front and approaching upper level storm system. The cold front will move through the area after 00Z Sunday.
These winds will continue Saturday evening with a wind shift to northwest expected around sunrise Sunday due to the passage of a Pacific cold front. Shower and thunderstorm chances will increase area wide Saturday and Saturday night as an upper level low moves out from northern New Mexico across the Texas Panhandle and southern Oklahoma. The upper level low will move into Arkansas by midday Sunday. Meanwhile a Pacific cold front will move through the region Saturday night and Sunday morning. In the wake of the cold front expect gusty northwesterly winds Sunday.
Confidence: High Rain ongoing across the central to northern portions of Iowa will continue to propagate northeastward with the low. As of now, it appears any sensible effects and precip from this low should remain just south of Iowa.
Fog and drizzle continues to spread into the region with the moist feed ahead of the upper low system shifting toward the western Great Lakes region. Radars show a band of light showers moving northward this morning ahead of aN 850 MB warm front. Temperatures early this morning ranged from a few degrees above freezing over central and northeast Wisconsin to near freezing across north central Wisconsin. Reports from last evening over north central Wisconsin along with latest state road report early this morning suggest a continued support for the winter weather advisory for the north this morning for mainly freezing drizzle. Light precipitation will shift northward tonight into Sunday as the upper low system lifts to Lake Superior.
The dense fog has recently shown some expansion into parts of north central Wisconsin while the higher terrain of the remainer of western Wisconsin was also likely experiencing dense fog.
Highs today in the upper 30s along the Pine Ridge in northern Sheridan county with 40s over the remainder of the forecast area with light west winds becoming northwest this evening.
Low-level moisture along the southern edge of the low was resulting in stratus clouds extending across much of the outlook area. The cloud cover from this scattered light precipitation will aid in keeping temperatures warmer overnight with lows only dropping into the mid/upper 30s over that region.
However, after 00z, ceilings and visibilities will drop at each terminal to MVFR to IFR levels as another round of showers moves into the region from the SW along a warm front.
Forecast soundings keep the low level moisture in place and have no reason to expect anything other than overcast skies.
301 AM CST Sat Jan 21 2017 Manual 00z upper-air analysis and early-morning water vapor imagery indicate the presence of a high-amplitude wave pattern over the lower 48 states. In the low levels, a moist air mass which has contributed to areas of dense fog and drizzle/rain showers early this morning will become displaced by a drier boundary-layer advecting into the the mid MO Valley from the west and northwest.
An upper trough, which extends from a low centered off the Washington coast, will weaken and lift to the north today. Scattered showers will continue across SE Oregon and SW Idaho through the day, with rain/snow showers in the lower valleys and snow showers in the higher elevations. A second and stronger low pressure system will approach the PacNW coast and stall offshore on Sunday. Greater amounts are expected in the Lower Treasure Valley.
A continuation of low clouds/fog/areas of light freezing drizzle across mainly central North Dakota is the theme for the short term period. Far western North Dakota will mostly be detached from the worst of the fog and any freezing drizzle threat at this time. The result will be for more of the same with clouds/areas of fog and light freezing drizzle initially. BUFKIT soundings indicate supercooled water droplets in the saturated layer with enough vertical motion for light freezing drizzle. High temperatures Saturday will be similar to Fridays, especially with the low cloud canopy remaining overhead. Sounding profiles moisten up through the column allowing for a transition from light freezing drizzle/light freezing rain to light snow Saturday night into Sunday.
we should transition into more of a scattered light rain and/or drizzle scenario with strong isentropic lift continuing to go along with the low ceilings. Models crop up some scattered activity during the day with divergence aloft and while still warm, tomorrow with more clouds and less wind may be a tad cooler.
Although the low clouds have been lifting all day, the clearing line will progress northeast through the area mostly after sunset. With the upper low just south of the area, lapse rates aloft are fairly steep, so thunderstorms are a decent bet along with the showers. This period will feature a pattern change, to a cooler and drier regime. The persistent upper level trough over the western U. will be replaced by a ridge, resulting in a downstream trough forming over the eastern U.
Meanwhile, forecast soundings show a plume of increasing instability arriving from the south, with the highest of values spanning southern areas. *Impacts_Severe: If the low-level jet and associated storms find their way into our southeastern counties, there will be another risk of tornadic activity, hail, and damaging straight-line winds. Additionally, colder air aloft associated with the parent upper low is forecast to spread across Alabama through Sunday.