Alan Crone's Weather Blog: Winter Storm Pushes Into State

Wednesday, March 4th 2015, 4:04 am
By: Alan Crone

The cold front continues to surge southward bringing strong north winds and much colder air to the state this morning.   Relatively warmer and moist air is being drawn up and over the shallow dome of cold air producing precipitation across the state this morning.   Winter weather advisories are posted until midnight for a large portion of Oklahoma, including the eastern third of the state. Please check the top of our main web page for up-to-date listings of advisories or warnings.  The latest “trend" in the model data is supporting lower amounts of accumulation compared to yesterday afternoon data.  Overall accumulations across northeastern OK will range from 1 to 3 inches with some locally higher amounts to the east-southeast of the metro.  

Light precipitation continues to develop across northern OK this morning with temperatures near freezing.   This will create a small window for some light freezing rain (rain freezing on contact) across the northern sections of northeastern OK.   The colder and deeper air-mass will move southward as the day progresses allowing the rain to transition to sleet and then finally snow by midday to afternoon.   The exact transition times will have major implications on the total accumulation forecast for this event.   Our timing is such to support some rain to freezing rain from 7am to 5am, transitioning from rain to sleet between 8am to 10am, and then to snow by noon  to afternoon.   These time periods are rough estimates and intended for the northeastern portion of the state, including the Tulsa metro.  Locations to the north will see these periods of transition about 1 to 2 hours faster.   

Locations along the I-40 corridor region southward into southeastern OK will see a longer period of rain this morning transitioning to freezing rain later in the morning.   This may continue until noon to early afternoon before transitioning to sleet and eventually all snow by late this afternoon and tonight.   As an example, locations near Muskogee could see rain changing to freezing rain around 8am to 10am.   A transition to a winter mix would occur around 11am to 2pm with all snow from late afternoon into the evening hours.   Locations near McAlester may see rain this morning changing to some freezing rain between 10am to 2pm.   A transition to sleet would occur around 2pm then mixing to and changing to snow by late afternoon into the evening.   This will support slightly higher icing accumulations across part of southeastern and far southern sections of east central OK.    A strip of .10 to .15 inches of ice is possible across part of Choctaw, Pushmataha, Mccurtain, and southern Leflore Counties.  A few of these counties across extreme southeastern OK are being placed in winter storm warnings due to the possibility of some icing combined with the expected sleet and snow totals.   Please keep in mind times listed are rough estimates.  

Our friends at the NWS have placed the expiration times for the current winter weather advisory as midnight.  The back end of the system will be clearing the region later this evening as the main upper level trough swings east of the state.   

Once we get this disturbance away from the region, the pattern appears favorable for a nice stretch of weather into the weekend.   There will be some lingering impacts of the winter system Thursday morning.     This will have a tendency to keep our Thursday afternoon highs slightly cooler .   This means Thursday morning will start in the mid-teens and end from 34 to 36 with sunshine and light winds.   

Friday into the weekend features morning lows in the 20s and 30s.   Friday afternoon highs may end up in the upper 40s, or it could go into the lower 50s.   This will depend upon how quickly the surface cover erodes.   We'll be optimistic and keep our current Friday high of 52.  Even if we end up in the upper 40s, the sunshine will offer a nice day.   The weekend highs should move into the mid and upper 50s with sunshine and light wind.   A weak wind shift will arrive Saturday, but that's probably the only impact on sensible weather conditions.   This is the " time change" weekend.  Check those batteries in the smoke detector and " spring forward" Saturday night late.  

As with many winter weather events, small scale influences in the atmosphere can create wide variations of precipitation totals over a relatively small area.   Last week is a great example of the influence of small-scale banding and forcing.   Let's see how this even unfolds over the next few hours.   Additional changes to the forecast are always possible.  Please check back later today.   

Thanks for reading the Wednesday Morning weather discussion and blog. 

Have a safe day.    Drive slowly and leave plenty of room between cars on the roadway later today. 

Alan Crone