Friday, February 14, 2020

Friday Night - Clear. Low: 22-26

Saturday - Overcast. High: 42-46

Saturday Night - Scattered Clouds.  High: 26-30

Sunday - Partially Cloudy.  High: 46-50

Monday -  Rainy.  High: 50-54

Thanks to for the icons!

For this weekend, we expect warmer temperatures than today.  This weekend the flow is more zonal which indicates that we should expect quieter weather.  However going into Monday we expect precipitation in the form of rainfall though it may be a maximum of 0.25 inches. 
Forecasters: Balkissoon, Munley, Travis
Issued:  5:00pm: February 14, 2020

Technical Discussion (The nerdy stuff we are discussing in class) 

For today's analyses, we will be using a both the GFS, NAM and SREF outputs as the WPC's model diagnostics preference.

Today's low temperature can be attributed to our northward position of the jet as seen in 250 hPa map.  Throughout the remainder of the weekend the flow becomes more zonal as there are no significant strong troughs and ridges thus the expectation of quiet weather.  Similarly for 500 hPa map of relative vorticity, over the weekend there is no significant longwaves or shortwaves  as such we don't see much circulation over our area over the weekend.  However, today since we sit on a base of a trough of a shortwave where there is a counterclockwise wind flow, we incur positive curvature.  Together with the increased shear indicative of the higher change in wind speed over the horizontal contours implies we have increase vorticity over the region.  We observed this from the map.

From the 700 hPa RH and Omega map, there is no moisture over Northern Missouri until Saturday at 12Z however, there is no significant lift (Omega = -1).  Similarly, Sunday at 18Z we have the same situation.   On Monday at 18Z, looking at this map, we observed that precipitation is hindered once again not because the lack of moisture in the atmosphere but the UVM.  Consulting the GFS Skew-Ts we observe the best chances of rain is on Monday from 3pm to 6pm as we do have the combination of these two parameters.  This is supported by the NAM run which puts us at a max of 0.25 inches on Monday at 3pm.  From the SREF, the models average output does show precipitation fro Monday.

From the 850 hPa map, we also see  the transitioning from colder to warmer temperatures from Friday to Saturday.  We observe this from the change in the direction in which the wind is blowing; it changes from the North-West to South-West. Warm air from the NW is blowing through our region.  We see further support of this when we look at the 1000-500  hPa thickness.  The thickness contours are more dense on Saturday than Friday.  From the hypsometric equation delta z is proportional to average temperature, thus we expect our temperatures to rise on Saturday.  From this map, we also observe that the pressure contours are perpendicular to the thickness contours indicative of WAA.     

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