Friday Weather Update


Friday, March 4th 2011, 5:20 am
By: News On 6


Update:

The front is starting to finally move in our direction.

The forecast remains in decent shape at this point and the chance of scattered showers and storms will remain this afternoon through tonight.

 A shallow inversion may continue to prohibit thunderstorm development today across eastern OK as the front approaches the area.  But as the upper level support arrives from the west, colder air aloft will begin to erode and change the thermal profile.  Additionally, the data supports the possibility of thunderstorms behind the boundary this afternoon and early evening.  Buf kit data indicates pockets of elevated cape (convective and potential energy) that could also provide the potential for a few strong to near severe storms even behind the boundary.  Large hail would be the main threat with these elevated storms.

 If discrete storms can form ahead of the front in far eastern OK, super cellular structures would be possible.  This probability remains rather low. 

 I have left the morning post intact below.  Nick Bender will be in the office this afternoon and tonight with forecast and storm updates if needed.

From earlier this morning:

Forecast confidence Today = 7

Issues= timing of the front and the initiation of storms.

 

 Forecast confidence for Monday through Thursday = 8

Issues= exact temps for Monday.  Storm Chances Tuesday.

  

The cold front is to our west-northwest this morning and will slowly move eastward through day.  The front will be entering the Tulsa area between 2pm and 3pm and then exiting southeastern OK around 10 pm to midnight. There will be a chance of storms today across the eastern third of the state and a few may be severe. Model data is indicating the possibility of post frontal precipitation across northern OK Friday afternoon and early evening.  Other showers and storms may also form behind the front across northeastern OK including the Tulsa metro by early afternoon.   This activity is not expected to be severe.  Most post frontal precip usually falls in the form of non thunder showers.  The upper level trough will be still near the area and the air aloft will be very cold.  This will create the possibility of post frontal thunder with some small hail potential. 

A cap, or layer of warm air aloft may suppress thunderstorm activity for most of the day ahead of the boundary.  If this layer erodes, severe storms will be likely.

 The deeper and colder air will move across the state early Saturday morning along with gusty north winds at 10 to 25 mph.  Most of the moisture will be depleted from the atmosphere at this point, but there's always a chance we may see a brief area of showers or even snow flurries tomorrow morning.  This probability remains near 10%.  

 Wind speeds Saturday morning may be on the strong side before the winds drop down in speed by the late afternoon.  North winds will advect cold air (moving horizontally) across the area.  These winds will back to the southeast by Sunday evening and advect low level moisture back across the state by Monday or Tuesday in advance of the next major storm system.

 

The Tuesday trough will be very powerful for early spring.  If low level moisture (quality and deep moisture) can move back in place before this system arrives, a severe weather episode would be possible.  We'll need to watch this time period very closely. 

 

Another major concern for this period which has a much higher level of confidence is the fire danger concerns for Monday and Tuesday.  If the projected wind speeds occur Monday and Tuesday, the fire danger across central and western OK will be of the highest concern.  Areas of western OK may be on the back side of the dry line Tuesday.  This would place western OK in a low moisture field with westerly winds nearing 40 mph.  I'm usually very conservative about pre-storm and pre-event messages, but I feel the need to stress the awareness of the fire danger during this time period.  Eastern OK will also be in the high fire danger category Monday, but not as high on Tuesday due to the increasing moisture content. 

 

The GFS and EURO data (the models I use for most of the later extended potions) have both been overall too cool for the Wednesday time period.  I bought this solution a few days ago and had highs Wednesday in the lower 40s.  I'm considering raising these temperatures to the upper 40s or even lower 50s for Wednesday based on the increasing sun angle for the time period. 

  

What's a dry line?

A dry line is a weather feature, similar to a boundary that separates warm and moist air to the east from dry and usually hot air from the west.  The dry line is mainly associated with moisture content.  During early spring the temperature contrast is usually very subtle, but during summer, the temperature contrast can be very evident due to the nature of dry air heating efficiently.

Again, the main determining factor for identifying the dry line is moisture content in the form of dew point temperatures.

  

Years ago, I had this crazy idea of running for political office.  I was young. 

 

 I get all kinds of calls and emails with people complaining about all kinds of things:  my boots, my hair, my forecast.  The list goes on and on.  I can only imagine the complaints public servants must receive. If you work in the public sector, or serve in the public sector, Thanks for serving.