Cool, dismal weather persists

Public weather briefing

Weak southerly to southwesterly flow around a high pressure area centered over Tennessee and Kentucky will continue to provide weak subsidence over southern Wisconsin through Friday. While clearing skies today teased us with the prospect of warmer weather, the presence of a strong inversion will keep the atmosphere from mixing warmer air aloft down to the surface. The continued southerly flow will gradually moisten and provide increasing clouds and the increasing threat of drizzle  or light rain later in the weekend.

The weather system bringing much need rain to the western US will head eastward across the Rocky Mountains and emerge into  southern Plains on Sunday morning before heading northeast toward southern Wisconsin later Sunday. Initially the precipitation associated with the weather system will be rain.  As the system tracks over then northeast of the state on Monday night, colder air will return - changing the rain to snow early Tuesday morning. Clearing will follow Tuesday afternoon with northwesterly winds. Colder, but likely dry weather is expected for Wednesday

Forecast 

Tonight. Mostly cloudy and cold. Light southwest winds 5 mph. Lows 23.

Friday. Partly to mostly cloudy and cool. Light southwest winds 8 mph. High around 37.

Friday night. Cloudy.  Low 27.

Saturday. Partly to mostly cloudy. Milder. Light winds. High 45. Low around 33.

Sunday. Cloudy with light rain possible. Rain developing late. High near 47. Low. 38

Outlook for Monday through Wednesday. Rain Monday High around 40. Rain changing to snow late Monday night and early Tuesday. Snow and snow showers on Tuesday, high around freezing early with steady then slowly falling temperatures Tuesday afternoon. Partly cloudy and breezy Wednesday, high 30, low 20. [CONFIDENCE: MEDIUM]

Forecast Discussion

An upper ridge crests over the upper Midwest late week providing subsidence while further strengthening the stubborn inversion over the area. With the ridge firmly in place, surface temperatures will be slow to rise;  while at 850 hPa, temperatures will rise from 4C this evening to 11C by Saturday afternoon. Advection of warm and an increasingly moist air from the southern Plains will increase clouds and the threat for light rain on Sunday.

A potent shortwave trough will approach the area on Monday. The arrival of the sharp trough will be accompanied by significant upper tropospheric divergence and concomitant ascent. With significant northward moisture transport from the Gulf, a descent rainfall is possible late on Monday.  The 0000 UTC 12 December  GFS tracks the surface cyclone associated with the upper trough more to the north than in earlier runs.  This track will hasten the transition of rain to snow relative to earlier forecasts and, with subsidence behind the upper trough, potentially clear the area sooner on Tuesday.  

Forecast confidence in the medium range is medium due to the uncertainty in the track of the shortwave from the southwestern US this evening to the midwest Monday night.  This uncertainty is manifest in the changing model evolution seen in recent runs. 

Michael C. Morgan

Unseasonably Warm Temperatures on tap for the Weekend

Public weather briefing

Cloudy and rather calm conditions will prevail for the remainder of the week with slowly warming temperatures as an area of high pressure moves off to our east. The persistence of light winds into the weekend will encourage the development of patchy fog during the overnight hours. The next chance of precipitation will be during the latter half of the weekend as light showers may develop in conjunction with warm front pushing north through southern Wisconsin on Saturday night. A developing low pressure system brings a renewed, and more likely chance, of rain on Monday with a transition to light snow showers and cooler temperatures around normal (32) on Tuesday.

Forecast 

Tonight. Cloudy with areas of fog, particularly in low-lying areas. Low temperatures around 22 with light and variable winds.

Thursday. Mostly cloudy with light west-northwesterly winds around 5 mph. High around 31.

Thursday night. Mostly cloudy with light westerly winds. Areas of patchy fog.  Low around 26.

Friday. Mostly cloudy with west-southwesterly winds 5-10 mph. High around 39. Patchy fog developing overnight with lows around 30.

Saturday. Mostly Cloudy with a chance of showers developing Saturday night. West-southwesterly winds 5-10 mph. High around 43. Low around 39.

Outlook for Sunday through Tuesday. Slight chance of rain showers on Sunday with greater chances of rain on Monday. Rain should taper off Monday night and transition over to light snow showers. Mostly cloudy skies should prevail on Tuesday with a lingering chance of flurries.  Temperatures should rise as high as the mid-to-upper 40's on Sunday and Monday before falling back into the lower 30's for Tuesday. [CONFIDENCE: MEDIUM-HIGH]

Forecast Discussion

The persistence of a 500 hPa ridge axis to the west of Wisconsin has positioned a region of mid-tropospheric subsidence firmly over southern Wisconsin for the past couple of days, producing a rather strong temperature inversion around 850 hPa in the 12Z soundings at GRB and DVN. With a surface anticyclone located over Illinois, light winds have struggled to erode the inversion, indicating that cloudy conditions are likely to continue overnight into Thursday. With the lower-troposphere near saturation, areas of patchy fog are likely to develop.

Throughout the day Thursday and Friday, the surface anticyclone over Illinois is forecasted to slide slightly off to the east, allowing for winds to increase slightly, though by not much, towards the end of the week and aiding in the erosion of the strong temperature inversion above the surface. West-southwesterly winds will also advect slightly warmer temperatures into southern Wisconsin into the day on Friday. With winds remaining light during the overnight hours, patchy fog will once again become a forecast issue.

The passage of a warm front on Saturday will help foster the chance for light rain showers on Saturday evening in conjunction with an area of Qs convergence. At the moment, areas north and west of the Madison area are most likely to experience these rain showers. A greater chance of rain will occur Sunday night and into Monday with a cyclone forecasted to develop over the Central Plains. The GFS depicts the deepening and tightening of a trough now located over the central Pacific as it propagates eastward into the central US. Strong PVA associated with this trough will encourage the development of a surface cyclone and active lower-tropospheric frontogenesis along the warm front stretched over southern Wisconsin. Temperatures will likely be above freezing throughout much of Monday so rain is expected over southern Wisconsin at this point. A transition to light snow showers is expected as the cyclone slides to our south and east on Monday night into Tuesday with temperatures falling back to around normal in the lower-30's. 

Andrew Winters

Warm Weekend Outlook

Public weather briefing

After a cloudy Tuesday, the good chance for clear conditions into the rest of the week continues. High pressure moves into the area tomorrow from Canada, providing calm conditions for the week ahead.  Along with this, another high pressure system from the Rockies has an impact in the region later in the week providing for more mild conditions.  Low temperatures tonight will be cold at just below 20 degrees.  Daytime high temperatures will slowly increase throughout the week providing for a very comfortable weekend, temperature wise.  It is looking very likely for above 40 degree highs for the weekend.  Partly to mostly sunny skies are the main feature for the middle to end of the week, before the clouds return for end of the weekend.  Also, the possibility for rain or snow comes into the picture at the start of next week.  Attributed to this is a low pressure system to the west along the Great Plains and north into Canada.

Forecast 

Tonight. Partly cloudy and light winds. Low around 20.

Wednesday. Mostly sunny with light winds. High around 30.

Wednesday night. Clear and cold.  Low in the upper teen's.

Thursday. Sunny and cool. Light winds. High of 35 and a low around 23.

Friday. Continued sun and warmer with a high in the upper 30's. Low in the mid 20's.

Outlook for Saturday through Monday. Clear Saturday, before clouds return Sunday and Monday. Very nice temperatures in the mid to up 40's for Saturday and Sunday before cooling to the upper 30's on Monday. There is likely going to be precipitation along with the cooling Monday. Probably a mix of snow and ice.[CONFIDENCE: MEDIUM-HIGH]

Forecast Discussion

The high pressure system from Canada will make its impact tomorrow and the subsidence associated to this anticyclone will deliver clearing skies for the end of the week.  Associated with this, are light winds and partly to mostly sunny conditions.  Anticyclonic motions provide descending air, which is adiabatically warming, would reduce the amount of relative humidity throughout the region limiting the amount of cloud cover.  Throughout the next few days, cold but consistent temperatures move in from the north will be providing seasonal temperatures of around 30-35 degrees.  

Late Thursday, into Friday, a secondary anticyclone from the Rockies, mentioned yesterday is likely to travel through the southern plains and eventually keep moving west to east through the central U.S., missing the upper Midwest to the south.  The effects are still felt however, as there will be warm air advection from the south giving us warmer than average temperatures for the weekend.  Along with this are clear conditions for most of the weekend as well.

Later in the forecast, Sunday, a low pressure trough pushes its way south from Canada into the Wisconsin region.  This brings ascending air and clouds return to the forecast along with a small chance of showers. 

After this pressure trough from the north, a low pressure system to the southwest, centered over the Great Plains brings in colder conditions and a good chance for a rain/snow mix on Monday.  There will most likely be rain during the morning/afternoon when temperatures are higher, and then snow once the cold front moves in and daytime highs end.

Will Hahn and Andrew Goenner

Calm Week Ahead

Public weather briefing

After a cold, rainy, and icy Monday morning and afternoon, clearing conditions and average afternoon temperatures, for this time of year, are anticipated for the week ahead.  The rainfall from this morning and early-to-mid afternoon will clear out this evening with the area of rain moving from west to east out of the region.  High pressure moves into the area, within the next day or so from Canada, providing calm conditions for the week ahead.  Along with this, another high pressure system from the Rockies arrives in the region later in the week providing for more mild conditions.  Low temperatures tonight and tomorrow will be a bit chilly hitting just below 20 degrees.  Daytime high temperatures will slowly increase throughout the week providing for a very comfortable weekend, temperature wise.  Partly to mostly sunny skies are the main feature of the middle of the week, before the clouds return for the weekend.

Forecast 

Tonight. Rain should clear out after 8 pm.  Moderate northwest wind at about 10 mph with lows in the middle 20's.

Tuesday. Partly sunny with some clouds, along with light to moderate winds. High in the middle 30's, around 34.

Tuesday night. A few clouds, but mostly clear and very cold.  Low in the upper teen's.

Wednesday. Sunny and cool. Light winds. High around 30. Very cold low, once again, in the upper teen's

Thursday. Mostly sunny. High near 35.

Outlook for Friday through Sunday. Warmer temperatures arrive for the weekend.  High in the low 40's for Friday, and middle 40's for Saturday and Sunday.  Along with the warmer temperatures, the clouds return as it is likely to be partly to mostly for the most of the weekend.  [CONFIDENCE: HIGH]

Forecast Discussion

Subsidence accompanying the arrival of a main anticyclone from Canada within the next day will provide clearing skies.  Associated with this, are light winds and partly to mostly sunny conditions.  Anticyclonic motions provide descending air, which is adiabatically warming, would reduce the amount of relative humidity throughout the region limiting the amount of cloud cover.  Throughout the next few days, cold but consistent temperatures move in from the north will be providing seasonal temperatures of around 30-35 degrees.  

Late Thursday, into Friday, a secondary anticyclone from the Rockies travels through the southern plains to the Great Lakes area, making its effect on the state, Friday and into the weekend.  Associated with this secondary height ridge is warm air advection from the south giving us warmer than average temperatures for the weekend.

Another item to mention are the GFS temperatures given at the 850 hPa level for the weekend.  

According the temperatures given at 850 hPa of about 8-10 degrees Celsius, if this air is brought down to the surface, we should expect temperatures of about 16 degrees Celsius or 60 degrees Fahrenheit.  However, this is the maximum temperature the surface could reach given the correct conditions.  At this time of the year, with the sun at its lowest angle and shortest duration in the sky, this would limit daytime heating.  Along with this, calm winds at the surface, due to the high pressure ridge, would provide very little mixing within the boundary layer, which would once again inhibit the high temperatures from reaching 60 degrees Fahrenheit.  

Overall, it should be a pretty nice week and the warm temperatures over the weekend will be welcomed after the past month of brutally cold temperatures.

Will Hahn and Andrew Goenner

Chance of Freezing Rain Moves South; Pleasant Weekend Ahead!

Public weather briefing

 Partly cloudy skies prevail into the end of the work week, as chances of precipitation shift further south for Friday.  A very slight chance of precipitation remains for midday Friday.  Saturday will be nicer, with sun and temperatures in the low 30s. Conditions remain pleasant through Sunday evening, when we will see the next chance of precipitation into Monday afternoon.  Agreeable weather returns for Tuesday and Wednesday.

Forecast 

Tonight. Partly cloudy skies with light winds. Lows around 25.

Friday. Cloudy with light winds, with a very slight chance of precipitation. High in the mid-30's.

Friday night. Mostly cloudy skies.  Lows around 25.

Saturday. Clearing skies with light winds. High of 32, low around 20

Sunday. Partly sunny, with light winds. High of 35, low of 28.

Outlook for Monday through Wednesday. Clouds returning on Sunday evening, with a slight chance of snow. Chances of precipitation linger through mid-Monday, with skies partly cloudy for Tuesday and Wednesday. Highs in the lower to mid 30's Monday through Wednesday. Lows in the mid 20's. [CONFIDENCE: MEDIUM-HIGH]

Forecast Discussion

The high pressure system that has influenced the weather over past few days has began to move towards the east. A low pressure system that originated off of the Baja peninsula of California will propagate eastward, passing south of the Madison area by mid-Friday. Warm air advection will accompany the system, with temperatures reaching the mid 30s by the weekend. Subsidence associated with a high pressure system will dominate the weekend weather, with clear skies Saturday. 

The next chance for possible precipitation is Sunday night through Monday afternoon. A maximum in positive vorticity is located over southern Minnesota. Positive vorticity will be advected towards Madison on Monday morning, increasing chances of ascent in the area, and therefore possible precipitation.  The chance of precipitation will end late Monday afternoon as the trough propagates towards the east.  Subsidence will follow once more, due to negative vorticity advection.  Yet another high pressure system will enter the region early Tuesday, bringing partly cloudy skies and temperature highs in the mid 30's



Elizabeth Schenk

Lindsey Nytes

Freezing Rain Possible for Case Study "Due-ms Day"

Public weather briefing

Cloudy skies on Thursday will give way to chances of precipitation starting Thursday night into Friday. The near-freezing temperatures indicate a risk of freezing rain. Precipitation will start moving out of the area by late Friday, and end completely by midnight. Saturday will be nicer, with sun and temperatures in the mid 30s. Conditions remain pleasant through Sunday evening, when we will see the next chance of precipitation into Monday afternoon.

Forecast 

Tonight. Partly cloudy skies with light winds. Lows around 10.

Thursday. Partly cloudy with light winds. High in the upper 20's.

Thursday night. Mostly cloudy skies with a slight chance of freezing rain.  Lows in the low 30's.

Friday. Cloudy skies, with a chance of freezing rain. High 36. Low around 26.

Saturday. Clearing skies, with light winds. High of 32, Low of 24.

Outlook for Sunday through Tuesday. Clouds returning on Sunday, with a slight chance of snow in the evening. Chances of precipitation linger through Monday, with skies clearing by Tuesday. Highs in the mid 30's Sunday and Monday, cooler on Tuesday. Lows in the mid 20's. [CONFIDENCE: MEDIUM-HIGH]

Forecast Discussion

The high pressure system that has influenced the weather over past few days will move on eastward. A low pressure system that originated off of the Baja peninsula of California will propagate eastward, reaching the Madison area by mid-Friday. Warm air advection will accompany the system, allowing highs to surpass the monthly average temperature of 32, reaching the upper 30s by the end of the work week. Subsidence associated with a high pressure system will dominate the weekend weather, with clear skies Saturday and Sunday. 

The next chance for precipitation will occur Sunday night through Monday afternoon. An upper level trough with a base over Iowa will advect positive vorticity due to thermal wind around midnight on Sunday, allowing for moist air to rise over southern Wisconsin. The chance of precipitation will end Monday afternoon as the trough propagates towards the east.  Subsidence will follow once more, due to negative vorticity advection. 



Elizabeth Schenk

Lindsey Nytes

Week of Warming

Public weather briefing

As temperatures began to warm up throughout the day, we expect Madison to remain cloudy until the weekend.  Although there is some small chance of precipitation in our area, we do not expect any significant snow accumulation.  Low temperatures tonight will be around 20, and will drop down tomorrow night, but the rest of the week should see a continuing warming trend.  Daytime high temperatures will slowly increase to the upper 30's by the weekend with partly sunny skies, but strong winds out of the north and east will make it feel a bit cooler.  The weekend is shaping up to be much nicer than the previous, and should even continue through the following week.

Forecast 

Tonight. Cloudy and cool.  Low in the lower 20's. Small chance of precipitation.

Wednesday. Very sunny and the high will be 30 with winds out of the northwest at about 20 knots.

Wednesday night. Partly cloudy and cooler.  Low around 15 with weaker winds out of the north.

Thursday.  Mostly cloudy with a high again at 30 and winds out of the southeast around 10 knots. Clouds persist into the night with a low of 25.

Friday. Cloudy high in the upper 30's.

Outlook for Saturday through Monday. Partly cloudy Saturday through Monoday with highs reaching the mid to upper 30's and very little chance of precipitation. Lows in the mid to upper 20's. [CONFIDENCE: Medium-High]

Forecast Discussion

Tuesday night will be mostly cloudy, insulating the surface temperatures and by preventing radiative cooling.  Northwesterly winds overnight will advect a moderate cold air mass, affecting most of the Midwest.  Clouds will persist through the middle to the end of the week limiting daily highs, but raising the overnight lows. bringing up the high temperature, but cloudy into the night insulating the area making a warmer low.  A low-level ridge will move through on early Sunday, initially advecting significant warm air into Madison making for our warmest temperatures over the weekend.   (average daily high temperature for later in the week 32F; low 22F).

The most difficult part of our forecast is determining the possibility of precipitation tonight, as a linear cold front appears to be moving west to east in northern in Wisconsin. It is expected that the precipitation associated will remain north of the Madison area, but some models show a slight chance of precipitation in southern Wisconsin.

Rachel Down and Sam Hartwick

Week of Warming

Public weather briefing

After a chilly and snowy thanksgiving break, the temperature will be expected to increase by Tuesday afternoon and remain constant throughout the rest of the week.  We expect no precipitation during the week, which could lead to some significant snowmelt over the weekend.  Low temperatures tonight will be in the single digits, but will increase tomorrow into the rest of the week.  Daytime high temperatures will slowly increase to the upper 30's this week with mostly sunny skies, but strong winds out of the south and west will make it feel a bit cooler.  The weekend is shaping up to be very nice, and should even continue through early next week.

Forecast 

Tonight. Partly cloudy with a low in the single digits around 5.

Tuesday. Partly sunny and the high will be 30 with winds out of the southwest at about 18 knots.

Tuesday night. Cloudy and cool.  Low in the lower 20's.

Wednesday. Sunny with a high again at 30 and winds out of the west around 20 knots. Cooling off into the night down to mid teens.

Thursday. Partly cloudy high in the upper 20's.

Outlook for Friday through Sunday. Partly cloudy Friday, Saturday and Sunday with highs consistently in the mid 30's and almost no chance of precipitation. Lows in the upper 20's. [CONFIDENCE: High]

Forecast Discussion

Subsidence accompanying the passage of an anticyclone over the upper-midwest this evening will provide clearing skies for the night.  With stronger winds and clear skies, radiational cooling will be maximized leading to frigid Monday night.  Tuesday will be mostly sunny bringing up the high temperature, but cloudy into the night insulating the area making a warmer low.  A small amount of cold air advection will bring a slight cool-down on Wednesday, but this gives way to a low level ridge to the east on Thursday into Friday, bringing in warm air for the rest of the week.  (average daily high temperature for later in the week 35F; low 20F).

The only wrinkle in an otherwise dry forecast for the week, is a descending cyclonic feature from the north that extends a pressure trough into northern Wisconsin.  The thickness contours over Wisconsin at this time are oriented southwest to northeast, indicating that the band of precipitation will be forced away from southern Wisconsin. Unless this orientation changes, this forecast should remain dry into the weekend.

Rachel Down and Sam Hartwick