Wednesday, October 21, 2015

Bring an Umbrella Friday Night

Public weather briefing

Following a few light showers today, the evening is expected to be clear.  Gradual cooling will occur over the next few days into the weekend.  A clear day is expected for tomorrow followed by a high likelihood of rain beginning on Friday evening and continuing into Saturday morning.  Temperatures will be around 60 this weekend with partly cloudy skies until Sunday night when there is a chance of rain.  Temperatures will remain moderate into next week.  


Tonight. A few clouds. Low around 43.

Thursday. Mostly clear. High around 64.

Thursday night.  Partly cloudy.  Lows in the low 40s.

Friday. Cloudy with rain beginning in the evening. Moderate winds. Highs around 60 and lows in the upper 50s.

Saturday. Rain into the morning with cloudy skies later in the day.  High of around 58.  Lows around 40.  

Outlook for Sunday through Tuesday. For Sunday through Tuesday Highs should be about 60 with lows in the evening of around 45. A slight chance of rain exists Sunday night followed by a cloudy Monday and a chance of scattered thunderstorms Tuesday.  [CONFIDENCE: MEDIUM]

Forecast Discussion

A cold front associated with a low centered over Ontario will pass through the region this evening with cool and dry air following in behind.  The dry air will reduce clouds into the night and Thursday Morning.  Skies will be partly cloudy on Thursday.  Then, a Colorado Low moving through the plains will reach southwestern Minnesota by Friday afternoon, forcing differential warm air advection to the east of its center. At this time, showers may begin.  A short wave trough will provide the means to lift the warm and moist air with its downstream, upper level divergence located above Wisconsin.  In addition, modeling of Q-Vector convergence indicates strong upward vertical motion that will also aid in the production of precipitation into Saturday morning.  Subsidence and more dry air following the event will make for a calm Saturday and Sunday.  

Alexander F. Fox

1 comment:

  1. This is an excellent forecast with very little error in the forecast for the high and low temperatures compared to the observed readings, as well as little error in the periods of rainfall. Friday night and Saturday morning saw increases in temperature - against the typical trend of the diurnal cycle - which could have been highlighted more strongly in the forecast. Also, the helpfulness of this forecast could be improved by including a comment of the intensity of the rainfall or an estimate of the amount of precipitation that is likely to occur. This forecast discussion provides an excellent diagnosis of the atmospheric features that are aiding the forecast of the weather. There is nice use of Q-vector convergence to diagnose the continued rainfall on Saturday morning, which ultimately did occur.


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